Go is a high-level, general-purpose programming language that is statically typed and compiled. It is known for the simplicity of its syntax and the efficiency of development that it enables through the inclusion of a large standard library supplying many needs for common projects.
Update Sep 5, 2024 tracked by Updatify
go1.22.7 (released 2024-09-05) includes security fixes to the encoding/gob, go/build/constraint, and go/parser packages, as well as bug fixes to the fix command and the runtime. See the Go 1.22.7 milestone on our issue tracker for details.
Update Aug 13, 2024 tracked by Updatify
The latest Go release, version 1.23, arrives six months after Go 1.22. Most of its changes are in the implementation of the toolchain, runtime, and libraries. As always, the release maintains the Go 1 promise of compatibility. We expect almost all Go programs to continue to compile and run as before.
The “range” clause in a “for-range” loop now accepts iterator functions of the following types
func(func() bool)
func(func(K) bool)
func(func(K, V) bool)
as range expressions.
Calls of the iterator argument function produce the iteration values for the “for-range” loop.
For details see the iter package documentation, the language spec, and the Range over Function
Types blog post.
For motivation see the 2022 “range-over-func” discussion.
Go 1.23 includes preview support for generic type aliases.
Building the toolchain with GOEXPERIMENT=aliastypeparams enables this feature within a package.
(Using generic alias types across package boundaries is not yet supported.)
Starting in Go 1.23, the Go toolchain can collect usage and breakage statistics that help the Go team understand how the Go toolchain is used and how well it is working. We refer to these statistics as Go telemetry.
Go telemetry is an opt-in system, controlled by the go telemetry command.
By default, the toolchain programs
collect statistics in counter files that can be inspected locally
but are otherwise unused ( go telemetry local).
To help us keep Go working well and understand Go usage,
please consider opting in to Go telemetry by running go telemetry on.
In that mode,
anonymous counter reports are uploaded to telemetry.go.dev weekly,
where they are aggregated into graphs and also made
available for download by any Go contributors or users
wanting to analyze the data.
See “ Go Telemetry ” for more details
about the Go Telemetry system.
Setting the GOROOT_FINAL environment variable no longer has an effect
( #62047).
Distributions that install the go command to a location other than $GOROOT/bin/go should install a symlink instead of relocating
or copying the go binary.
The new go env -changed flag causes the command to print only
those settings whose effective value differs from the default value
that would be obtained in an empty environment with no prior uses of the -w flag.
The new go mod tidy -diff flag causes the command not to modify
the files but instead print the necessary changes as a unified diff.
It exits with a non-zero code if updates are needed.
The go list -m -json command now includes new Sum and GoModSum fields.
This is similar to the existing behavior of the go mod download -json command.
The new godebug directive in go.mod and go.work declares a GODEBUG setting to apply for the work module or workspace in use.
The go vet subcommand now includes the stdversion analyzer, which flags references to symbols that are too new for the version
of Go in effect in the referring file. (The effective version is determined
by the go directive in the file’s enclosing go.mod file, and
by any //go:build constraints in the file.)
For example, it will report a diagnostic for a reference to the reflect.TypeFor function (introduced in go1.22) from a file in a
module whose go.mod file specifies go 1.21.
cmd/cgo supports the new -ldflags flag for passing flags to the C linker.
The go command uses it automatically, avoiding “argument list too long”
errors with a very large CGO_LDFLAGS.
The trace tool now better tolerates partially broken traces by attempting to
recover what trace data it can. This functionality is particularly helpful when
viewing a trace that was collected during a program crash, since the trace data
leading up to the crash will now be recoverable under most
circumstances.
The traceback printed by the runtime after an unhandled panic or other fatal error now indents the second and subsequent lines of the error message (for example, the argument to panic) by a single tab, so that it can be unambiguously distinguished from the stack trace of the first goroutine. See #64590 for discussion.
The build time overhead to building with Profile Guided Optimization has been reduced significantly. Previously, large builds could see 100%+ build time increase from enabling PGO. In Go 1.23, overhead should be in the single digit percentages.
The compiler in Go 1.23 can now overlap the stack frame slots of local variables accessed in disjoint regions of a function, which reduces stack usage for Go applications.
For 386 and amd64, the compiler will use information from PGO to align certain
hot blocks in loops. This improves performance an additional 1-1.5% at
a cost of an additional 0.1% text and binary size. This is currently only implemented
on 386 and amd64 because it has not shown an improvement on other platforms.
Hot block alignment can be disabled with -gcflags=[<packages>=]-d=alignhot=0.
The linker now disallows using a //go:linkname directive to refer to
internal symbols in the standard library (including the runtime) that
are not marked with //go:linkname on their definitions.
Similarly, the linker disallows references to such symbols from assembly
code.
For backward compatibility, existing usages of //go:linkname found in
a large open-source code corpus remain supported.
Any new references to standard library internal symbols will be disallowed.
A linker command line flag -checklinkname=0 can be used to disable
this check, for debugging and experimenting purposes.
When building a dynamically linked ELF binary (including PIE binary), the
new -bindnow flag enables immediate function binding.
Go 1.23 makes two significant changes to the implementation of time.Timer and time.Ticker.
First, Timer s and Ticker s that are no longer referred to by the program
become eligible for garbage collection immediately, even if their Stop methods have not been called.
Earlier versions of Go did not collect unstopped Timer s until after
they had fired and never collected unstopped Ticker s.
Second, the timer channel associated with a Timer or Ticker is
now unbuffered, with capacity 0.
The main effect of this change is that Go now guarantees
that for any call to a Reset or Stop method, no stale values
prepared before that call will be sent or received after the call.
Earlier versions of Go used channels with a one-element buffer,
making it difficult to use Reset and Stop correctly.
A visible effect of this change is that len and cap of timer channels
now returns 0 instead of 1, which may affect programs that
poll the length to decide whether a receive on the timer channel
will succeed.
Such code should use a non-blocking receive instead.
These new behaviors are only enabled when the main Go program
is in a module with a go.mod go line using Go 1.23.0 or later.
When Go 1.23 builds older programs, the old behaviors remain in effect.
The new GODEBUG setting asynctimerchan=1 can be used to revert back to asynchronous channel behaviors
even when a program names Go 1.23.0 or later in its go.mod file.
The new unique package provides facilities for
canonicalizing values (like “interning” or “hash-consing”).
Any value of comparable type may be canonicalized with the new Make[T] function, which produces a reference to a canonical copy of
the value in the form of a Handle[T].
Two Handle[T] are equal if and only if the values used to produce the
handles are equal, allowing programs to deduplicate values and reduce
their memory footprint.
Comparing two Handle[T] values is efficient, reducing down to a simple
pointer comparison.
The new iter package provides the basic definitions for working with
user-defined iterators.
The slices package adds several functions that work with iterators:
Sorted but with a
comparison function. SortFunc but uses a stable sort algorithm.
The maps package adds several functions that work with iterators:
The new structs package provides
types for struct fields that modify properties of
the containing struct type such as memory layout.
In this release, the only such type is HostLayout which indicates that a structure with a field of that
type has a layout that conforms to host platform
expectations. HostLayout should be used in types that
are passed to, returned from, or accessed
via a pointer passed to/from host APIs.
Without this marker, struct layout order is not
guaranteed by the language spec, though as of Go 1.23
the host and language layouts happen to match.
archive/tar
If the argument to FileInfoHeader implements the new FileInfoNames interface, then the interface methods will be used to set the Uname/Gname
of the file header. This allows applications to override the system-dependent
Uname/Gname lookup.
crypto/tls
The TLS client now supports the Encrypted Client Hello draft specification.
This feature can be enabled by setting the Config.EncryptedClientHelloConfigList field to an encoded ECHConfigList for the host that is being connected to.
The QUICConn type used by QUIC implementations includes new events
reporting on the state of session resumption, and provides a way for
the QUIC layer to add data to session tickets and session cache entries.
3DES cipher suites were removed from the default list used when Config.CipherSuites is nil. The default can be reverted by adding tls3des=1 to
the GODEBUG environment variable.
The experimental post-quantum key exchange mechanism X25519Kyber768Draft00
is now enabled by default when Config.CurvePreferences is nil.
The default can be reverted by adding tlskyber=0 to the GODEBUG environment variable.
This can be useful when dealing with buggy TLS servers that do not handle large records correctly,
causing a timeout during the handshake (see TLS post-quantum TL;DR fail).
Go 1.23 changed the behavior of X509KeyPair and LoadX509KeyPair to populate the Certificate.Leaf field of the returned Certificate.
The new x509keypairleaf GODEBUG setting is added for this behavior.
crypto/x509
CreateCertificateRequest now correctly supports RSA-PSS signature algorithms.
CreateCertificateRequest and CreateRevocationList now verify the generated signature using the signer’s public key. If the signature is invalid, an error is returned. This has been the behavior of CreateCertificate since Go 1.16.
The x509sha1 GODEBUG setting will
be removed in the next Go major release (Go 1.24). This will mean that crypto/x509 will no longer support verifying signatures on certificates that use SHA-1 based
signature algorithms.
The new ParseOID function parses a dot-encoded ASN.1 Object Identifier string.
The OID type now implements the encoding.BinaryMarshaler, encoding.BinaryUnmarshaler, encoding.TextMarshaler, encoding.TextUnmarshaler interfaces.
database/sql
Errors returned by driver.Valuer implementations are now wrapped for
improved error handling during operations like DB.Query, DB.Exec,
and DB.QueryRow.
debug/elf
The debug/elf package now defines PT_OPENBSD_NOBTCFI. This ProgType is
used to disable Branch Tracking Control Flow Integrity (BTCFI) enforcement
on OpenBSD binaries.
Now defines the symbol type constants STT_RELC, STT_SRELC, and STT_GNU_IFUNC.
encoding/binary
The new Encode and Decode functions are byte slice equivalents
to Read and Write. Append allows marshaling multiple data into the same byte slice.
go/ast
The new Preorder function returns a convenient iterator over all the
nodes of a syntax tree.
go/types
The Func type, which represents a function or method symbol, now
has a Func.Signature method that returns the function’s type, which
is always a Signature.
The Alias type now has an Rhs method that returns the type on the
right-hand side of its declaration: given type A = B, the Rhs of A
is B. ( #66559)
The methods Alias.Origin, Alias.SetTypeParams, Alias.TypeParams,
and Alias.TypeArgs have been added. They are needed for generic alias types.
By default, go/types now produces Alias type nodes for type aliases.
This behavior can be controlled by the GODEBUG gotypesalias flag.
Its default has changed from 0 in Go 1.22 to 1 in Go 1.23.
math/rand/v2
The Uint function and Rand.Uint method have been added.
They were inadvertently left out of Go 1.22.
The new ChaCha8.Read method implements the io.Reader interface.
net
The new type KeepAliveConfig permits fine-tuning the keep-alive
options for TCP connections, via a new TCPConn.SetKeepAliveConfig method and new KeepAliveConfig fields for Dialer and ListenConfig.
The DNSError type now wraps errors caused by timeouts or cancellation.
For example, errors.Is(someDNSErr, context.DeadlineExceedeed) will now report whether a DNS error was caused by a timeout.
The new GODEBUG setting netedns0=0 disables sending EDNS0
additional headers on DNS requests, as they reportedly break the DNS
server on some modems.
net/http
Cookie now preserves double quotes surrounding a cookie value.
The new Cookie.Quoted field indicates whether the Cookie.Value was originally quoted.
The new Request.CookiesNamed method retrieves all cookies that match the given name.
The new Cookie.Partitioned field identifies cookies with the Partitioned attribute.
The patterns used by ServeMux now allow one or more spaces or tabs after the method name.
Previously, only a single space was permitted.
The new ParseCookie function parses a Cookie header value and
returns all the cookies which were set in it. Since the same cookie
name can appear multiple times the returned Values can contain
more than one value for a given key.
The new ParseSetCookie function parses a Set-Cookie header value and
returns a cookie. It returns an error on syntax error.
ServeContent, ServeFile, and ServeFileFS now remove
the Cache-Control, Content-Encoding, Etag, and Last-Modified headers when serving an error. These headers usually apply to the
non-error content, but not to the text of errors.
Middleware which wraps a ResponseWriter and applies on-the-fly
encoding, such as Content-Encoding: gzip, will not function after
this change. The previous behavior of ServeContent, ServeFile,
and ServeFileFS may be restored by setting GODEBUG=httpservecontentkeepheaders=1.
Note that middleware which changes the size of the served content
(such as by compressing it) already does not function properly when ServeContent handles a Range request. On-the-fly compression
should use the Transfer-Encoding header instead of Content-Encoding.
For inbound requests, the new Request.Pattern field contains the ServeMux pattern (if any) that matched the request. This field is not set when GODEBUG=httpmuxgo121=1 is set.
net/http/httptest
The new NewRequestWithContext method creates an incoming request with
a context.Context.
net/netip
In Go 1.22 and earlier, using reflect.DeepEqual to compare an Addr holding an IPv4 address to one holding
the IPv4-mapped IPv6 form of that address incorrectly returned true,
even though the Addr values were different when comparing with == or Addr.Compare.
This bug is now fixed and all three approaches now report the same
result.
os
The Stat function now sets the ModeSocket bit for
files that are Unix sockets on Windows. These files are identified
by having a reparse tag set to IO_REPARSE_TAG_AF_UNIX.
On Windows, the mode bits reported by Lstat and Stat for
reparse points changed. Mount points no longer have ModeSymlink set,
and reparse points that are not symlinks, Unix sockets, or dedup files
now always have ModeIrregular set.
This behavior is controlled by the winsymlink setting.
For Go 1.23, it defaults to winsymlink=1.
Previous versions default to winsymlink=0.
The CopyFS function copies an io/fs.FS into the local filesystem.
On Windows, Readlink no longer tries to normalize volumes
to drive letters, which was not always even possible.
This behavior is controlled by the winreadlinkvolume setting.
For Go 1.23, it defaults to winreadlinkvolume=1.
Previous versions default to winreadlinkvolume=0.
On Linux with pidfd support (generally Linux v5.4+), Process -related functions and methods use pidfd (rather
than PID) internally, eliminating potential mistargeting when a PID is reused
by the OS. Pidfd support is fully transparent to a user, except for additional
process file descriptors that a process may have.
path/filepath
The new Localize function safely converts a slash-separated
path into an operating system path.
On Windows, EvalSymlinks no longer evaluates mount points,
which was a source of many inconsistencies and bugs.
This behavior is controlled by the winsymlink setting.
For Go 1.23, it defaults to winsymlink=1.
Previous versions default to winsymlink=0.
On Windows, EvalSymlinks no longer tries to normalize
volumes to drive letters, which was not always even possible.
This behavior is controlled by the winreadlinkvolume setting.
For Go 1.23, it defaults to winreadlinkvolume=1.
Previous versions default to winreadlinkvolume=0.
reflect
The new methods synonymous with the methods of the same name
in Value are added to Type:
The new SliceAt function is analogous to NewAt, but for slices.
The Value.Pointer and Value.UnsafePointer methods now support values of kind String.
The new methods Value.Seq and Value.Seq2 return sequences that iterate over the value
as though it were used in a for/range loop.
The new methods Type.CanSeq and Type.CanSeq2 report whether calling Value.Seq and Value.Seq2, respectively, will succeed without panicking.
runtime/debug
The SetCrashOutput function allows the user to specify an alternate
file to which the runtime should write its fatal crash report.
It may be used to construct an automated reporting mechanism for all
unexpected crashes, not just those in goroutines that explicitly use recover.
runtime/pprof
The maximum stack depth for alloc, mutex, block, threadcreate and goroutine profiles has been raised from 32 to 128 frames.
runtime/traceThe runtime now explicitly flushes trace data when a program crashes due to an uncaught panic. This means that more complete trace data will be available in a trace if the program crashes while tracing is active.
slices
The Repeat function returns a new slice that repeats the
provided slice the given number of times.
sync
The Map.Clear method deletes all the entries, resulting in
an empty Map. It is analogous to clear.
sync/atomic
The new And and Or operators apply a bitwise AND or OR to
the given input, returning the old value.
syscall
The syscall package now defines WSAENOPROTOOPT on Windows.
The GetsockoptInt function is now supported on Windows.
testing/fstest
TestFS now returns a structured error that can be unwrapped
(via method Unwrap() []error). This allows inspecting errors
using errors.Is or errors.As.
text/templateTemplates now support the new “else with” action, which reduces template complexity in some use cases.
time
Parse and ParseInLocation now return an error if the time zone
offset is out of range.
On Windows, Timer, Ticker, and functions that put the goroutine to sleep,
such as Sleep, got their time resolution improved to 0.5ms instead of 15.6ms.
unicode/utf16
The RuneLen function returns the number of 16-bit words in
the UTF-16 encoding of the rune. It returns -1 if the rune
is not a valid value to encode in UTF-16.
As announced in the Go 1.22 release notes, Go 1.23 requires macOS 11 Big Sur or later; support for previous versions has been discontinued.
Go 1.23 is the last release that requires Linux kernel version 2.6.32 or later. Go 1.24 will require Linux kernel version 3.2 or later.
Go 1.23 adds experimental support for OpenBSD on 64-bit RISC-V ( GOOS=openbsd, GOARCH=riscv64).
Go 1.23 introduces a new GOARM64 environment variable, which specifies the minimum target version of the ARM64 architecture at compile time. Allowed values are v8.{0-9} and v9.{0-5}. This may be followed by an option specifying extensions implemented by target hardware. Valid options are ,lse and ,crypto.
The GOARM64 environment variable defaults to v8.0.
Go 1.23 introduces a new GORISCV64 environment variable, which selects the RISC-V user-mode application profile for which to compile. Allowed values are rva20u64 and rva22u64.
The GORISCV64 environment variable defaults to rva20u64.
The go_wasip1_wasm_exec script in GOROOT/misc/wasm has dropped support
for versions of wasmtime < 14.0.0.
Update Aug 6, 2024 tracked by Updatify
go1.22.6 (released 2024-08-06) includes fixes to the go command, the compiler, the linker, the trace command, the covdata command, and the bytes, go/types, and os/exec packages. See the Go 1.22.6 milestone on our issue tracker for details.
Update Aug 6, 2024 tracked by Updatify
go1.21.13 (released 2024-08-06) includes fixes to the go command, the covdata command, and the bytes package. See the Go 1.21.13 milestone on our issue tracker for details.
Update Jul 2, 2024 tracked by Updatify
go1.22.5 (released 2024-07-02) includes security fixes to the net/http package, as well as bug fixes to the compiler, cgo, the go command, the linker, the runtime, and the crypto/tls, go/types, net, net/http, and os/exec packages. See the Go 1.22.5 milestone on our issue tracker for details.
Update Jul 2, 2024 tracked by Updatify
go1.21.12 (released 2024-07-02) includes security fixes to the net/http package, as well as bug fixes to the compiler, the go command, the runtime, and the crypto/x509, net/http, net/netip, and os packages. See the Go 1.21.12 milestone on our issue tracker for details.
Update Jun 4, 2024 tracked by Updatify
go1.22.4 (released 2024-06-04) includes security fixes to the archive/zip and net/netip packages, as well as bug fixes to the compiler, the go command, the linker, the runtime, and the os package. See the Go 1.22.4 milestone on our issue tracker for details.
Update Jun 4, 2024 tracked by Updatify
go1.21.11 (released 2024-06-04) includes security fixes to the archive/zip and net/netip packages, as well as bug fixes to the compiler, the go command, the runtime, and the os package. See the Go 1.21.11 milestone on our issue tracker for details.
Update May 7, 2024 tracked by Updatify
go1.22.3 (released 2024-05-07) includes security fixes to the go command and the net package, as well as bug fixes to the compiler, the runtime, and the net/http package. See the Go 1.22.3 milestone on our issue tracker for details.
Update May 7, 2024 tracked by Updatify
go1.21.10 (released 2024-05-07) includes security fixes to the go command, as well as bug fixes to the net/http package. See the Go 1.21.10 milestone on our issue tracker for details.
Update Apr 3, 2024 tracked by Updatify
go1.22.2 (released 2024-04-03) includes a security fix to the net/http package, as well as bug fixes to the compiler, the go command, the linker, and the encoding/gob, go/types, net/http, and runtime/trace packages. See the Go 1.22.2 milestone on our issue tracker for details.
Update Apr 3, 2024 tracked by Updatify
go1.21.9 (released 2024-04-03) includes a security fix to the net/http package, as well as bug fixes to the linker, and the go/types and net/http packages. See the Go 1.21.9 milestone on our issue tracker for details.
Update Mar 5, 2024 tracked by Updatify
go1.22.1 (released 2024-03-05) includes security fixes to the crypto/x509, html/template, net/http, net/http/cookiejar, and net/mail packages, as well as bug fixes to the compiler, the go command, the runtime, the trace command, and the go/types and net/http packages. See the Go 1.22.1 milestone on our issue tracker for details.
Update Mar 5, 2024 tracked by Updatify
go1.21.8 (released 2024-03-05) includes security fixes to the crypto/x509, html/template, net/http, net/http/cookiejar, and net/mail packages, as well as bug fixes to the go command and the runtime. See the Go 1.21.8 milestone on our issue tracker for details.
Update Feb 6, 2024 tracked by Updatify
The latest Go release, version 1.22, arrives six months after Go 1.21. Most of its changes are in the implementation of the toolchain, runtime, and libraries. As always, the release maintains the Go 1 promise of compatibility. We expect almost all Go programs to continue to compile and run as before.
Go 1.22 makes two changes to “for” loops.
package main import "fmt" func main() { for i := range 10 { fmt.Println(10 - i) } fmt.Println("go1.22 has lift-off!") } See the spec for details.
Go 1.22 includes a preview of a language change we are considering
for a future version of Go: range-over-function iterators.
Building with GOEXPERIMENT=rangefunc enables this feature.
Commands in workspaces can now
use a vendor directory containing the dependencies of the
workspace. The directory is created by go work vendor,
and used by build commands when the -mod flag is set to vendor, which is the default when a workspace vendor directory is present.
Note that the vendor directory’s contents for a workspace are different
from those of a single module: if the directory at the root of a workspace also
contains one of the modules in the workspace, its vendor directory
can contain the dependencies of either the workspace or of the module,
but not both.
go get is no longer supported outside of a module in the
legacy GOPATH mode (that is, with GO111MODULE=off).
Other build commands, such as go build and go test, will continue to work indefinitely
for legacy GOPATH programs.
go mod init no longer attempts to import
module requirements from configuration files for other vendoring tools
(such as Gopkg.lock).
go test -cover now prints coverage summaries
for covered packages that do not have their own test files. Prior to Go 1.22 a go test -cover run for such a package would
report
? mymod/mypack [no test files]
and now with Go 1.22, functions in the package are treated as uncovered:
mymod/mypack coverage: 0.0% of statements
Note that if a package contains no executable code at all, we can’t report
a meaningful coverage percentage; for such packages the go tool
will continue to report that there are no test files.
go build commands that invoke the linker now error out if an
external (C) linker will be used but cgo is not enabled. (The Go runtime
requires cgo support to ensure that it is compatible with any additional
libraries added by the C linker.)
The trace tool’s web UI has been gently refreshed as part of the
work to support the new tracer, resolving several issues and improving the
readability of various sub-pages.
The web UI now supports exploring traces in a thread-oriented view.
The trace viewer also now displays the full duration of all system calls.
These improvements only apply for viewing traces produced by programs built with
Go 1.22 or newer.
A future release will bring some of these improvements to traces produced by older
version of Go.
The behavior of the vet tool has changed to match
the new semantics (see above) of loop variables in Go 1.22.
When analyzing a file that requires Go 1.22 or newer
(due to its go.mod file or a per-file build constraint), vet no longer reports references to
loop variables from within a function literal that
might outlive the iteration of the loop.
In Go 1.22, loop variables are created anew for each iteration,
so such references are no longer at risk of using a variable
after it has been updated by the loop.
The vet tool now reports calls to append that pass
no values to be appended to the slice, such as slice = append(slice).
Such a statement has no effect, and experience has shown that is nearly always a mistake.
time.Since
The vet tool now reports a non-deferred call to time.Since(t) within a defer statement.
This is equivalent to calling time.Now().Sub(t) before the defer statement,
not when the deferred function is called. In nearly all cases, the correct code
requires deferring the time.Since call. For example:
t := time.Now()
defer log.Println(time.Since(t)) // non-deferred call to time.Since
tmp := time.Since(t); defer log.Println(tmp) // equivalent to the previous defer
defer func() {
log.Println(time.Since(t)) // a correctly deferred call to time.Since
}()
log/slog calls
The vet tool now reports invalid arguments in calls to functions and methods
in the structured logging package, log/slog,
that accept alternating key/value pairs.
It reports calls where an argument in a key position is neither a string nor a slog.Attr, and where a final key is missing its value.
The runtime now keeps type-based garbage collection metadata nearer to each heap object, improving the CPU performance (latency or throughput) of Go programs by 1–3%. This change also reduces the memory overhead of the majority Go programs by approximately 1% by deduplicating redundant metadata. Some programs may see a smaller improvement because this change adjusts the size class boundaries of the memory allocator, so some objects may be moved up a size class.
A consequence of this change is that some objects’ addresses that were previously
always aligned to a 16 byte (or higher) boundary will now only be aligned to an 8
byte boundary.
Some programs that use assembly instructions that require memory addresses to be
more than 8-byte aligned and rely on the memory allocator’s previous alignment behavior
may break, but we expect such programs to be rare.
Such programs may be built with GOEXPERIMENT=noallocheaders to revert
to the old metadata layout and restore the previous alignment behavior, but package
owners should update their assembly code to avoid the alignment assumption, as this
workaround will be removed in a future release.
On the windows/amd64 port, programs linking or loading Go libraries built with -buildmode=c-archive or -buildmode=c-shared can now use
the SetUnhandledExceptionFilter Win32 function to catch exceptions not handled
by the Go runtime. Note that this was already supported on the windows/386 port.
Profile-guided Optimization (PGO) builds can now devirtualize a higher proportion of calls than previously possible. Most programs from a representative set of Go programs now see between 2 and 14% improvement at runtime from enabling PGO.
The compiler now interleaves devirtualization and inlining, so interface method calls are better optimized.
Go 1.22 also includes a preview of an enhanced implementation of the compiler’s inlining phase that uses heuristics to boost inlinability at call sites deemed “important” (for example, in loops) and discourage inlining at call sites deemed “unimportant” (for example, on panic paths).
Building with GOEXPERIMENT=newinliner enables the new call-site
heuristics; see issue #61502 for
more info and to provide feedback.
The linker’s -s and -w flags are now behave more
consistently across all platforms.
The -w flag suppresses DWARF debug information generation.
The -s flag suppresses symbol table generation.
The -s flag also implies the -w flag, which can be
negated with -w=0.
That is, -s -w=0 will generate a binary with DWARF
debug information generation but without the symbol table.
On ELF platforms, the -B linker flag now accepts a special form:
with -B gobuildid, the linker will generate a GNU
build ID (the ELF NT_GNU_BUILD_ID note) derived from the Go
build ID.
On Windows, when building with -linkmode=internal, the linker now
preserves SEH information from C object files by copying the .pdata and .xdata sections into the final binary.
This helps with debugging and profiling binaries using native tools, such as WinDbg.
Note that until now, C functions’ SEH exception handlers were not being honored,
so this change may cause some programs to behave differently. -linkmode=external is not affected by this change, as external linkers
already preserve SEH information.
As mentioned in the Go 1.20 release notes, Go 1.22 now requires the final point release of Go 1.20 or later for bootstrap. We expect that Go 1.24 will require the final point release of Go 1.22 or later for bootstrap.
Go 1.22 includes the first “v2” package in the standard library, math/rand/v2.
The changes compared to math/rand are
detailed in proposal #61716. The most important changes are:
Read method, deprecated in math/rand,
was not carried forward for math/rand/v2.
(It remains available in math/rand.)
The vast majority of calls to Read should use crypto/rand ’s Read instead.
Otherwise a custom Read can be constructed using the Uint64 method. Source interface now has a single Uint64 method;
there is no Source64 interface. math/rand because they changed the output streams. Intn, Int31, Int31n, Int63,
and Int64n top-level functions and methods from math/rand are spelled more idiomatically in math/rand/v2: IntN, Int32, Int32N, Int64,
and Int64N.
There are also new top-level functions and methods Uint32, Uint32N, Uint64, Uint64N,
and UintN. N is like Int64N or Uint64N but works for any integer type.
For example a random duration from 0 up to 5 minutes is rand.N(5*time.Minute). math/rand ’s Source has been replaced by two more modern pseudo-random generator sources: ChaCha8 and PCG.
ChaCha8 is a new, cryptographically strong random number generator
roughly similar to PCG in efficiency.
ChaCha8 is the algorithm used for the top-level functions in math/rand/v2.
As of Go 1.22, math/rand ’s top-level functions (when not explicitly seeded)
and the Go runtime also use ChaCha8 for randomness. We plan to include an API migration tool in a future release, likely Go 1.23.
The new go/version package implements functions
for validating and comparing Go version strings.
HTTP routing in the standard library is now more expressive.
The patterns used by net/http.ServeMux have been enhanced to accept methods and wildcards.
Registering a handler with a method, like "POST /items/create", restricts
invocations of the handler to requests with the given method. A pattern with a method takes precedence over a matching pattern without one.
As a special case, registering a handler with "GET" also registers it with "HEAD".
Wildcards in patterns, like /items/{id}, match segments of the URL path.
The actual segment value may be accessed by calling the Request.PathValue method.
A wildcard ending in “…”, like /files/{path...}, must occur at the end of a pattern and matches all the remaining segments.
A pattern that ends in “/” matches all paths that have it as a prefix, as always.
To match the exact pattern including the trailing slash, end it with {$},
as in /exact/match/{$}.
If two patterns overlap in the requests that they match, then the more specific pattern takes precedence. If neither is more specific, the patterns conflict. This rule generalizes the original precedence rules and maintains the property that the order in which patterns are registered does not matter.
This change breaks backwards compatibility in small ways, some obvious—patterns with “{” and “}” behave differently—
and some less so—treatment of escaped paths has been improved.
The change is controlled by a GODEBUG field named httpmuxgo121.
Set httpmuxgo121=1 to restore the old behavior.
As always, there are various minor changes and updates to the library, made with the Go 1 promise of compatibility in mind. There are also various performance improvements, not enumerated here.
archive/tar
: The new method Writer.AddFS adds all of the files from an fs.FS to the archive.
archive/zip
: The new method Writer.AddFS adds all of the files from an fs.FS to the archive.
bufio
: When a SplitFunc returns ErrFinalToken with a nil token, Scanner will now stop immediately.
Previously, it would report a final empty token before stopping, which was usually not desired.
Callers that do want to report a final empty token can do so by returning []byte{} rather than nil.
cmp
: The new function Or returns the first in a sequence of values that is not the zero value.
crypto/tls
: ConnectionState.ExportKeyingMaterial will now
return an error unless TLS 1.3 is in use, or the extended_master_secret extension is supported by both the server and
client. crypto/tls has supported this extension since Go 1.20. This can be disabled with the tlsunsafeekm=1 GODEBUG setting. By default, the minimum version offered by crypto/tls servers is now TLS 1.2 if not specified with config.MinimumVersion, matching the behavior of crypto/tls clients. This change can be reverted with the tls10server=1 GODEBUG setting. By default, cipher suites without ECDHE support are no longer offered by either clients or servers during pre-TLS 1.3
handshakes. This change can be reverted with the tlsrsakex=1 GODEBUG setting.
crypto/x509
: The new CertPool.AddCertWithConstraint method can be used to add customized constraints to root certificates to be applied during chain building. On Android, root certificates will now be loaded from /data/misc/keychain/certs-added as well as /system/etc/security/cacerts. A new type, OID, supports ASN.1 Object Identifiers with individual
components larger than 31 bits. A new field which uses this type, Policies,
is added to the Certificate struct, and is now populated during parsing. Any OIDs which cannot be represented
using a asn1.ObjectIdentifier will appear in Policies,
but not in the old PolicyIdentifiers field.
When calling CreateCertificate, the Policies field is ignored, and
policies are taken from the PolicyIdentifiers field. Using the x509usepolicies=1 GODEBUG setting inverts this,
populating certificate policies from the Policies field, and ignoring the PolicyIdentifiers field. We may change the
default value of x509usepolicies in Go 1.23, making Policies the default field for marshaling.
database/sql
: The new Null[T] type
provide a way to scan nullable columns for any column types.
debug/elf
: Constant R_MIPS_PC32 is defined for use with MIPS64 systems. Additional R_LARCH_* constants are defined for use with LoongArch systems.
encoding
: The new methods AppendEncode and AppendDecode added to
each of the Encoding types in the packages encoding/base32, encoding/base64, and encoding/hex simplify encoding and decoding from and to byte slices by taking care of byte slice buffer management. The methods base32.Encoding.WithPadding and base64.Encoding.WithPadding now panic if the padding argument is a negative value other than NoPadding.
encoding/json
: Marshaling and encoding functionality now escapes '\b' and '\f' characters as \b and \f instead of \u0008 and \u000c.
go/ast
: The following declarations related to syntactic identifier resolution are now deprecated: Ident.Obj, Object, Scope, File.Scope, File.Unresolved, Importer, Package, NewPackage.
In general, identifiers cannot be accurately resolved without type information.
Consider, for example, the identifier K in T{K: ""}: it could be the name of a local variable
if T is a map type, or the name of a field if T is a struct type.
New programs should use the go/types package to resolve identifiers; see Object, Info.Uses, and Info.Defs for details. The new ast.Unparen function removes any enclosing parentheses from
an expression.
go/types
: The new Alias type represents type aliases.
Previously, type aliases were not represented explicitly, so a reference to a type alias was equivalent
to spelling out the aliased type, and the name of the alias was lost.
The new representation retains the intermediate Alias.
This enables improved error reporting (the name of a type alias can be reported), and allows for better handling
of cyclic type declarations involving type aliases.
In a future release, Alias types will also carry type parameter information.
The new function Unalias returns the actual type denoted by an Alias type (or any other Type for that matter). Because Alias types may break existing type switches that do not know to check for them,
this functionality is controlled by a GODEBUG field named gotypesalias.
With gotypesalias=0, everything behaves as before, and Alias types are never created.
With gotypesalias=1, Alias types are created and clients must expect them.
The default is gotypesalias=0.
In a future release, the default will be changed to gotypesalias=1. Clients of go/types are urged to adjust their code as soon as possible
to work with gotypesalias=1 to eliminate problems early. The Info struct now exports the FileVersions map
which provides per-file Go version information. The new helper method PkgNameOf returns the local package name
for the given import declaration. The implementation of SizesFor has been adjusted to compute
the same type sizes as the compiler when the compiler argument for SizesFor is "gc".
The default Sizes implementation used by the type checker is now types.SizesFor("gc", "amd64"). The start position ( Pos)
of the lexical environment block ( Scope)
that represents a function body has changed:
it used to start at the opening curly brace of the function body,
but now starts at the function’s func token.
html/template
: JavaScript template literals may now contain Go template actions, and parsing a template containing one will
no longer return ErrJSTemplate. Similarly the GODEBUG setting jstmpllitinterp no
longer has any effect.
io
: The new SectionReader.Outer method returns the ReaderAt, offset, and size passed to NewSectionReader.
log/slog
: The new SetLogLoggerLevel function
controls the level for the bridge between the slog and log packages. It sets the minimum level
for calls to the top-level slog logging functions, and it sets the level for calls to log.Logger that go through slog.
math/big
: The new method Rat.FloatPrec computes the number of fractional decimal digits
required to represent a rational number accurately as a floating-point number, and whether accurate decimal representation
is possible in the first place.
net
: When io.Copy copies
from a TCPConn to a UnixConn,
it will now use Linux’s splice(2) system call if possible,
using the new method TCPConn.WriteTo. The Go DNS Resolver, used when building with “-tags=netgo”,
now searches for a matching name in the Windows hosts file,
located at %SystemRoot%\System32\drivers\etc\hosts,
before making a DNS query.
net/http
: The new functions ServeFileFS, FileServerFS, and NewFileTransportFS are versions of the existing ServeFile, FileServer, and NewFileTransport,
operating on an fs.FS. The HTTP server and client now reject requests and responses containing
an invalid empty Content-Length header.
The previous behavior may be restored by setting GODEBUG field httplaxcontentlength=1. The new method Request.PathValue returns path wildcard values from a request
and the new method Request.SetPathValue sets path wildcard values on a request.
net/http/cgi
: When executing a CGI process, the PATH_INFO variable is now
always set to the empty string or a value starting with a / character,
as required by RFC 3875. It was previously possible for some combinations of Handler.Root and request URL to violate this requirement.
net/netip
: The new AddrPort.Compare method compares two AddrPort s.
os
: On Windows, the Stat function now follows all reparse points
that link to another named entity in the system.
It was previously only following IO_REPARSE_TAG_SYMLINK and IO_REPARSE_TAG_MOUNT_POINT reparse points. On Windows, passing O_SYNC to OpenFile now causes write operations to go directly to disk, equivalent to O_SYNC on Unix platforms. On Windows, the ReadDir, File.ReadDir, File.Readdir,
and File.Readdirnames functions
now read directory entries in batches to reduce the number of system calls,
improving performance up to 30%. When io.Copy copies
from a File to a net.UnixConn,
it will now use Linux’s sendfile(2) system call if possible,
using the new method File.WriteTo.
os/exec
: On Windows, LookPath now
ignores empty entries in %PATH%, and returns ErrNotFound (instead of ErrNotExist) if
no executable file extension is found to resolve an otherwise-unambiguous
name. On Windows, Command and Cmd.Start no
longer call LookPath if the path to the executable is already
absolute and has an executable file extension. In addition, Cmd.Start no longer writes the resolved extension back to
the Path field,
so it is now safe to call the String method concurrently
with a call to Start.
reflect
: The Value.IsZero method will now return true for a floating-point or complex
negative zero, and will return true for a struct value if a
blank field (a field named _) somehow has a
non-zero value.
These changes make IsZero consistent with comparing
a value to zero using the language == operator. The PtrTo function is deprecated,
in favor of PointerTo. The new function TypeFor returns the Type that represents
the type argument T.
Previously, to get the reflect.Type value for a type, one had to use reflect.TypeOf((*T)(nil)).Elem().
This may now be written as reflect.TypeFor[T]().
runtime/metrics
: Four new histogram metrics /sched/pauses/stopping/gc:seconds, /sched/pauses/stopping/other:seconds, /sched/pauses/total/gc:seconds, and /sched/pauses/total/other:seconds provide additional details
about stop-the-world pauses.
The “stopping” metrics report the time taken from deciding to stop the
world until all goroutines are stopped.
The “total” metrics report the time taken from deciding to stop the world
until it is started again. The /gc/pauses:seconds metric is deprecated, as it is
equivalent to the new /sched/pauses/total/gc:seconds metric. /sync/mutex/wait/total:seconds now includes contention on
runtime-internal locks in addition to sync.Mutex and sync.RWMutex.
runtime/pprof
: Mutex profiles now scale contention by the number of goroutines blocked on the mutex.
This provides a more accurate representation of the degree to which a mutex is a bottleneck in
a Go program.
For instance, if 100 goroutines are blocked on a mutex for 10 milliseconds, a mutex profile will
now record 1 second of delay instead of 10 milliseconds of delay. Mutex profiles also now include contention on runtime-internal locks in addition to sync.Mutex and sync.RWMutex.
Contention on runtime-internal locks is always reported at runtime._LostContendedRuntimeLock.
A future release will add complete stack traces in these cases. CPU profiles on Darwin platforms now contain the process’s memory map, enabling the disassembly
view in the pprof tool.
runtime/trace
: The execution tracer has been completely overhauled in this release, resolving several long-standing
issues and paving the way for new use-cases for execution traces. Execution traces now use the operating system’s clock on most platforms (Windows excluded) so
it is possible to correlate them with traces produced by lower-level components.
Execution traces no longer depend on the reliability of the platform’s clock to produce a correct trace.
Execution traces are now partitioned regularly on-the-fly and as a result may be processed in a
streamable way.
Execution traces now contain complete durations for all system calls.
Execution traces now contain information about the operating system threads that goroutines executed on.
The latency impact of starting and stopping execution traces has been dramatically reduced.
Execution traces may now begin or end during the garbage collection mark phase. To allow Go developers to take advantage of these improvements, an experimental
trace reading package is available at golang.org/x/exp/trace.
Note that this package only works on traces produced by programs built with Go 1.22 at the moment.
Please try out the package and provide feedback on the corresponding proposal issue. If you experience any issues with the new execution tracer implementation, you may switch back to the
old implementation by building your Go program with GOEXPERIMENT=noexectracer2.
If you do, please file an issue, otherwise this option will be removed in a future release.
slices
: The new function Concat concatenates multiple slices. Functions that shrink the size of a slice ( Delete, DeleteFunc, Compact, CompactFunc, and Replace) now zero the elements between the new length and the old length. Insert now always panics if the argument i is out of range. Previously it did not panic in this situation if there were no elements to be inserted.
syscall
: The syscall package has been frozen since Go 1.4 and was marked as deprecated in Go 1.11, causing many editors to warn about any use of the package.
However, some non-deprecated functionality requires use of the syscall package, such as the os/exec.Cmd.SysProcAttr field.
To avoid unnecessary complaints on such code, the syscall package is no longer marked as deprecated.
The package remains frozen to most new functionality, and new code remains encouraged to use golang.org/x/sys/unix or golang.org/x/sys/windows where possible. On Linux, the new SysProcAttr.PidFD field allows obtaining a PID FD when starting a child process via StartProcess or os/exec. On Windows, passing O_SYNC to Open now causes write operations to go directly to disk, equivalent to O_SYNC on Unix platforms.
testing/slogtest
: The new Run function uses sub-tests to run test cases,
providing finer-grained control.
On macOS on 64-bit x86 architecture (the darwin/amd64 port),
the Go toolchain now generates position-independent executables (PIE) by default.
Non-PIE binaries can be generated by specifying the -buildmode=exe build flag.
On 64-bit ARM-based macOS (the darwin/arm64 port),
the Go toolchain already generates PIE by default.
Go 1.22 is the last release that will run on macOS 10.15 Catalina. Go 1.23 will require macOS 11 Big Sur or later.
The GOARM environment variable now allows you to select whether to use software or hardware floating point.
Previously, valid GOARM values were 5, 6, or 7. Now those same values can
be optionally followed by ,softfloat or ,hardfloat to select the floating-point implementation.
This new option defaults to softfloat for version 5 and hardfloat for versions 6 and 7.
The loong64 port now supports passing function arguments and results using registers.
The linux/loong64 port now supports the address sanitizer, memory sanitizer, new-style linker relocations, and the plugin build mode.
Go 1.22 adds an experimental port to OpenBSD on big-endian 64-bit PowerPC
( openbsd/ppc64).
Update Feb 6, 2024 tracked by Updatify
go1.21.7 (released 2024-02-06) includes fixes to the compiler, the go command, the runtime, and the crypto/x509 package. See the Go 1.21.7 milestone on our issue tracker for details.
Update Feb 6, 2024 tracked by Updatify
go1.20.14 (released 2024-02-06) includes fixes to the crypto/x509 package. See the Go 1.20.14 milestone on our issue tracker for details.
Update Jan 9, 2024 tracked by Updatify
go1.21.6 (released 2024-01-09) includes fixes to the compiler, the runtime, and the crypto/tls, maps, and runtime/pprof packages. See the Go 1.21.6 milestone on our issue tracker for details.
Update Jan 9, 2024 tracked by Updatify
go1.20.13 (released 2024-01-09) includes fixes to the runtime and the crypto/tls package. See the Go 1.20.13 milestone on our issue tracker for details.
Update Dec 5, 2023 tracked by Updatify
go1.21.5 (released 2023-12-05) includes security fixes to the go command, and the net/http and path/filepath packages, as well as bug fixes to the compiler, the go command, the runtime, and the crypto/rand, net, os, and syscall packages. See the Go 1.21.5 milestone on our issue tracker for details.
Update Dec 5, 2023 tracked by Updatify
go1.20.12 (released 2023-12-05) includes security fixes to the go command, and the net/http and path/filepath packages, as well as bug fixes to the compiler and the go command. See the Go 1.20.12 milestone on our issue tracker for details.
Update Nov 7, 2023 tracked by Updatify
go1.21.4 (released 2023-11-07) includes security fixes to the path/filepath package, as well as bug fixes to the linker, the runtime, the compiler, and the go/types, net/http, and runtime/cgo packages. See the Go 1.21.4 milestone on our issue tracker for details.
Update Nov 7, 2023 tracked by Updatify
go1.20.11 (released 2023-11-07) includes security fixes to the path/filepath package, as well as bug fixes to the linker and the net/http package. See the Go 1.20.11 milestone on our issue tracker for details.
Update Oct 10, 2023 tracked by Updatify
go1.21.3 (released 2023-10-10) includes a security fix to the net/http package. See the Go 1.21.3 milestone on our issue tracker for details.
Update Oct 10, 2023 tracked by Updatify
go1.20.10 (released 2023-10-10) includes a security fix to the net/http package. See the Go 1.20.10 milestone on our issue tracker for details.
Update Oct 5, 2023 tracked by Updatify
go1.21.2 (released 2023-10-05) includes one security fix to the cmd/go package, as well as bug fixes to the compiler, the go command, the linker, the runtime, and the runtime/metrics package. See the Go 1.21.2 milestone on our issue tracker for details.
Update Oct 5, 2023 tracked by Updatify
go1.20.9 (released 2023-10-05) includes one security fix to the cmd/go package, as well as bug fixes to the go command and the linker. See the Go 1.20.9 milestone on our issue tracker for details.
Update Sep 6, 2023 tracked by Updatify
go1.21.1 (released 2023-09-06) includes four security fixes to the cmd/go, crypto/tls, and html/template packages, as well as bug fixes to the compiler, the go command, the linker, the runtime, and the context, crypto/tls, encoding/gob, encoding/xml, go/types, net/http, os, and path/filepath packages. See the Go 1.21.1 milestone on our issue tracker for details.
Update Sep 6, 2023 tracked by Updatify
go1.20.8 (released 2023-09-06) includes two security fixes to the html/template package, as well as bug fixes to the compiler, the go command, the runtime, and the crypto/tls, go/types, net/http, and path/filepath packages. See the Go 1.20.8 milestone on our issue tracker for details.
Update Sep 6, 2023 tracked by Updatify
go1.19.13 (released 2023-09-06) includes fixes to the go command, and the crypto/tls and net/http packages. See the Go 1.19.13 milestone on our issue tracker for details.
Update Aug 8, 2023 tracked by Updatify
The latest Go release, version 1.21, arrives six months after Go 1.20. Most of its changes are in the implementation of the toolchain, runtime, and libraries. As always, the release maintains the Go 1 promise of compatibility; in fact, Go 1.21 improves upon that promise. We expect almost all Go programs to continue to compile and run as before.
Go 1.21 introduces a small change to the numbering of releases.
In the past, we used Go 1. N to refer to both the overall Go language version and release family
as well as the first release in that family.
Starting in Go 1.21, the first release is now Go 1. N.0.
Today we are releasing both the Go 1.21 language and its initial implementation, the Go 1.21.0 release.
These notes refer to “Go 1.21”; tools like go version will report “ go1.21.0 ”
(until you upgrade to Go 1.21.1).
See “ Go versions ” in the “Go Toolchains” documentation for details
about the new version numbering.
Go 1.21 adds three new built-ins to the language.
min and max compute the
smallest (or largest, for max) value of a fixed number
of given arguments.
See the language spec for details. clear deletes all elements from a
map or zeroes all elements of a slice.
See the language spec for details. Package initialization order is now specified more precisely. The new algorithm is:
This may change the behavior of some programs that rely on a specific initialization ordering that was not expressed by explicit imports. The behavior of such programs was not well defined by the spec in past releases. The new rule provides an unambiguous definition.
Multiple improvements that increase the power and precision of type inference have been made.
More generally, the description of type inference in the language spec has been clarified. Together, all these changes make type inference more powerful and inference failures less surprising.
Go 1.21 includes a preview of a language change we are considering for a future version of Go: making for loop variables per-iteration instead of per-loop, to avoid accidental sharing bugs. For details about how to try that language change, see the LoopvarExperiment wiki page.
Go 1.21 now defines that if a goroutine is panicking and recover was called directly by a deferred
function, the return value of recover is guaranteed not to be nil. To ensure this, calling panic
with a nil interface value (or an untyped nil) causes a run-time panic of type *runtime.PanicNilError.
To support programs written for older versions of Go, nil panics can be re-enabled by setting GODEBUG=panicnil=1.
This setting is enabled automatically when compiling a program whose main package
is in a module that declares go 1.20 or earlier.
Go 1.21 adds improved support for backwards compatibility and forwards compatibility in the Go toolchain.
To improve backwards compatibility, Go 1.21 formalizes
Go’s use of the GODEBUG environment variable to control
the default behavior for changes that are non-breaking according to the compatibility policy but nonetheless may cause existing programs to break.
(For example, programs that depend on buggy behavior may break
when a bug is fixed, but bug fixes are not considered breaking changes.)
When Go must make this kind of behavior change,
it now chooses between the old and new behavior based on the go line in the workspace’s go.work file
or else the main module’s go.mod file.
Upgrading to a new Go toolchain but leaving the go line
set to its original (older) Go version preserves the behavior of the older
toolchain.
With this compatibility support, the latest Go toolchain should always
be the best, most secure, implementation of an older version of Go.
See “ Go, Backwards Compatibility, and GODEBUG ” for details.
To improve forwards compatibility, Go 1.21 now reads the go line
in a go.work or go.mod file as a strict
minimum requirement: go 1.21.0 means
that the workspace or module cannot be used with Go 1.20 or with Go 1.21rc1.
This allows projects that depend on fixes made in later versions of Go
to ensure that they are not used with earlier versions.
It also gives better error reporting for projects that make use of new Go features:
when the problem is that a newer Go version is needed,
that problem is reported clearly, instead of attempting to build the code
and printing errors about unresolved imports or syntax errors.
To make these new stricter version requirements easier to manage,
the go command can now invoke not just the toolchain
bundled in its own release but also other Go toolchain versions found in the PATH
or downloaded on demand.
If a go.mod or go.work go line
declares a minimum requirement on a newer version of Go, the go command will find and run that version automatically.
The new toolchain directive sets a suggested minimum toolchain to use,
which may be newer than the strict go minimum.
See “ Go Toolchains ” for details.
The -pgo build flag now defaults to -pgo=auto,
and the restriction of specifying a single main package on the command
line is now removed. If a file named default.pgo is present
in the main package’s directory, the go command will use
it to enable profile-guided optimization for building the corresponding
program.
The -C dir flag must now be the first
flag on the command-line when used.
The new go test option -fullpath prints full path names in test log messages,
rather than just base names.
The go test -c flag now
supports writing test binaries for multiple packages, each to pkg.test where pkg is the package name.
It is an error if more than one test package being compiled has a given package name.
The go test -o flag now
accepts a directory argument, in which case test binaries are written to that
directory instead of the current directory.
When using an external (C) linker with cgo enabled, the runtime/cgo package is
now supplied to the Go linker as an additional dependency to ensure that the Go
runtime is compatible with any additional libraries added by the C linker.
In files that import "C", the Go toolchain now
correctly reports errors for attempts to declare Go methods on C types.
When printing very deep stacks, the runtime now prints the first 50 (innermost) frames followed by the bottom 50 (outermost) frames, rather than just printing the first 100 frames. This makes it easier to see how deeply recursive stacks started, and is especially valuable for debugging stack overflows.
On Linux platforms that support transparent huge pages, the Go runtime
now manages which parts of the heap may be backed by huge pages more
explicitly. This leads to better utilization of memory: small heaps
should see less memory used (up to 50% in pathological cases) while
large heaps should see fewer broken huge pages for dense parts of the
heap, improving CPU usage and latency by up to 1%. A consequence of this
change is that the runtime no longer tries to work around a particular
problematic Linux configuration setting, which may result in higher
memory overheads. The recommended fix is to adjust the OS’s huge page
settings according to the GC guide.
However, other workarounds are available as well. See the section on max_ptes_none.
As a result of runtime-internal garbage collection tuning,
applications may see up to a 40% reduction in application tail latency
and a small decrease in memory use. Some applications may also observe
a small loss in throughput.
The memory use decrease should be proportional to the loss in
throughput, such that the previous release’s throughput/memory
tradeoff may be recovered (with little change to latency) by
increasing GOGC and/or GOMEMLIMIT slightly.
Calls from C to Go on threads created in C require some setup to prepare for Go execution. On Unix platforms, this setup is now preserved across multiple calls from the same thread. This significantly reduces the overhead of subsequent C to Go calls from ~1-3 microseconds per call to ~100-200 nanoseconds per call.
Profile-guide optimization (PGO), added as a preview in Go 1.20, is now ready
for general use. PGO enables additional optimizations on code identified as
hot by profiles of production workloads. As mentioned in the Go command section, PGO is enabled by default for
binaries that contain a default.pgo profile in the main
package directory. Performance improvements vary depending on application
behavior, with most programs from a representative set of Go programs seeing
between 2 and 7% improvement from enabling PGO. See the PGO user guide for detailed documentation.
PGO builds can now devirtualize some interface method calls, adding a concrete call to the most common callee. This enables further optimization, such as inlining the callee.
Go 1.21 improves build speed by up to 6%, largely thanks to building the compiler itself with PGO.
On amd64, frameless nosplit assembly functions are no longer automatically marked as NOFRAME.
Instead, the NOFRAME attribute must be explicitly specified if desired,
which is already the behavior on other architectures supporting frame pointers.
With this, the runtime now maintains the frame pointers for stack transitions.
The verifier that checks for incorrect uses of R15 when dynamic linking on amd64 has been improved.
On windows/amd64, the linker (with help from the compiler) now emits SEH unwinding data by default, which improves the integration of Go applications with Windows debuggers and other tools.
In Go 1.21 the linker (with help from the compiler) is now capable of deleting dead (unreferenced) global map variables, if the number of entries in the variable initializer is sufficiently large, and if the initializer expressions are side-effect free.
The new log/slog package provides structured logging with levels. Structured logging emits key-value pairs to enable fast, accurate processing of large amounts of log data. The package supports integration with popular log analysis tools and services.
The new testing/slogtest package can help to validate slog.Handler implementations.
The new slices package provides many common operations on slices, using generic functions that work with slices of any element type.
The new maps package provides several common operations on maps, using generic functions that work with maps of any key or element type.
The new cmp package defines the type
constraint Ordered and
two new generic functions Less and Compare that are
useful with ordered
types.
As always, there are various minor changes and updates to the library, made with the Go 1 promise of compatibility in mind. There are also various performance improvements, not enumerated here.
The implementation of the io/fs.FileInfo interface returned by Header.FileInfo now implements a String method that calls io/fs.FormatFileInfo.
The implementation of the io/fs.FileInfo interface returned by FileHeader.FileInfo now implements a String method that calls io/fs.FormatFileInfo.
The implementation of the io/fs.DirEntry interface returned by the io/fs.ReadDirFile.ReadDir method of the io/fs.File returned by Reader.Open now implements a String method that calls io/fs.FormatDirEntry.
The Buffer type
has two new methods: Available and AvailableBuffer.
These may be used along with the Write method to append directly to the Buffer.
The new WithoutCancel function returns a copy of a context that is not canceled when the original
context is canceled.
The new WithDeadlineCause and WithTimeoutCause functions provide a way to set a context cancellation cause when a deadline or
timer expires. The cause may be retrieved with the Cause function.
The new AfterFunc function registers a function to run after a context has been cancelled.
An optimization means that the results of calling Background and TODO and
converting them to a shared type can be considered equal.
In previous releases they were always different. Comparing Context values
for equality has never been well-defined, so this is not
considered to be an incompatible change.
PublicKey.Equal and PrivateKey.Equal now execute in constant time.
All of the Curve methods have been deprecated, along with GenerateKey, Marshal, and Unmarshal. For ECDH operations, the new crypto/ecdh package should be used instead. For lower-level operations, use third-party modules such as filippo.io/nistec.
The crypto/rand package now uses the getrandom system call on NetBSD 10.0 and later.
The performance of private RSA operations (decryption and signing) is now better than Go 1.19 for GOARCH=amd64 and GOARCH=arm64. It had regressed in Go 1.20.
Due to the addition of private fields to PrecomputedValues, PrivateKey.Precompute must be called for optimal performance even if deserializing (for example from JSON) a previously-precomputed private key.
PublicKey.Equal and PrivateKey.Equal now execute in constant time.
The GenerateMultiPrimeKey function and the PrecomputedValues.CRTValues field have been deprecated. PrecomputedValues.CRTValues will still be populated when PrivateKey.Precompute is called, but the values will not be used during decryption operations.
SHA-224 and SHA-256 operations now use native instructions when available when GOARCH=amd64, providing a performance improvement on the order of 3-4x.
Servers now skip verifying client certificates (including not running Config.VerifyPeerCertificate)
for resumed connections, besides checking the expiration time. This makes
session tickets larger when client certificates are in use. Clients were
already skipping verification on resumption, but now check the expiration
time even if Config.InsecureSkipVerify is set.
Applications can now control the content of session tickets.
SessionState type
describes a resumable session. SessionState.Bytes method and ParseSessionState function serialize and deserialize a SessionState. Config.WrapSession and Config.UnwrapSession hooks convert a SessionState to and from a ticket on the server side. Config.EncryptTicket and Config.DecryptTicket methods provide a default implementation of WrapSession and UnwrapSession. ClientSessionState.ResumptionState method and NewResumptionState function
may be used by a ClientSessionCache implementation to store and
resume sessions on the client side.
To reduce the potential for session tickets to be used as a tracking
mechanism across connections, the server now issues new tickets on every
resumption (if they are supported and not disabled) and tickets don’t bear
an identifier for the key that encrypted them anymore. If passing a large
number of keys to Conn.SetSessionTicketKeys,
this might lead to a noticeable performance cost.
Both clients and servers now implement the Extended Master Secret extension (RFC 7627).
The deprecation of ConnectionState.TLSUnique has been reverted, and is now set for resumed connections that support Extended Master Secret.
The new QUICConn type
provides support for QUIC implementations, including 0-RTT support. Note
that this is not itself a QUIC implementation, and 0-RTT is still not
supported in TLS.
The new VersionName function
returns the name for a TLS version number.
The TLS alert codes sent from the server for client authentication failures have been improved. Previously, these failures always resulted in a “bad certificate” alert. Now, certain failures will result in more appropriate alert codes, as defined by RFC 5246 and RFC 8446:
RevocationList.RevokedCertificates has been deprecated and replaced with the new RevokedCertificateEntries field, which is a slice of RevocationListEntry. RevocationListEntry contains all of the fields in pkix.RevokedCertificate, as well as the revocation reason code.
Name constraints are now correctly enforced on non-leaf certificates, and not on the certificates where they are expressed.
The new File.DynValue method may be used to retrieve the numeric values listed with a
given dynamic tag.
The constant flags permitted in a DT_FLAGS_1 dynamic tag are now defined with type DynFlag1. These
tags have names starting with DF_1.
The package now defines the constant COMPRESS_ZSTD.
The package now defines the constant R_PPC64_REL24_P9NOTOC.
Attempts to read from a section containing uninitialized data
using Section.Data or the reader returned by Section.Open now return an error.
The io/fs.File returned by FS.Open now
has a ReadAt method that
implements io.ReaderAt.
Calling [FS.Open](https://go.dev/pkg/embed/FS.Open).[Stat](https://go.dev/pkg/io/fs/#File.Stat) will return a type that now implements a String method that calls io/fs.FormatFileInfo.
The new NativeEndian variable may be used to convert between byte slices and integers
using the current machine’s native endianness.
The new ErrUnsupported error provides a standardized way to indicate that a requested
operation may not be performed because it is unsupported.
For example, a call to os.Link when using a
file system that does not support hard links.
The new BoolFunc function and FlagSet.BoolFunc method define a flag that does not require an argument and calls
a function when the flag is used. This is similar to Func but for a
boolean flag.
A flag definition
(via Bool, BoolVar, Int, IntVar, etc.)
will panic if Set has
already been called on a flag with the same name. This change is
intended to detect cases where changes in
initialization order cause flag operations to occur in a
different order than expected. In many cases the fix to this
problem is to introduce a explicit package dependence to
correctly order the definition before any Set operations.
The new IsGenerated predicate
reports whether a file syntax tree contains the special comment that conventionally indicates that the file was generated by a tool.
The new File.GoVersion field records the minimum Go version required by
any //go:build or // +build directives.
The package now parses build directives (comments that start
with //go:) in file headers (before
the package declaration). These directives are
available in the new Package fields Directives, TestDirectives,
and XTestDirectives.
The new GoVersion function returns the minimum Go version implied by a build
expression.
The new File.Lines method
returns the file’s line-number table in the same form as accepted by File.SetLines.
The new Package.GoVersion method returns the Go language version used to check the package.
The hash/maphash package now has a pure Go implementation, selectable with the purego build tag.
The new error ErrJSTemplate is returned when an action appears in a JavaScript template
literal. Previously an unexported error was returned.
The new FormatFileInfo function returns a formatted version of a FileInfo.
The new FormatDirEntry function returns a formatted version of a DirEntry.
The implementation of DirEntry returned by ReadDir now
implements a String method that calls FormatDirEntry,
and the same is true for
the DirEntry value passed to WalkDirFunc.
The new Int.Float64 method returns the nearest floating-point value to a
multi-precision integer, along with an indication of any
rounding that occurred.
On Linux, the net package can now use
Multipath TCP when the kernel supports it. It is not used by
default. To use Multipath TCP when available on a client, call
the Dialer.SetMultipathTCP method before calling the Dialer.Dial or Dialer.DialContext methods. To use Multipath TCP when available on a server, call
the ListenConfig.SetMultipathTCP method before calling the ListenConfig.Listen method. Specify the network as "tcp" or "tcp4" or "tcp6" as usual. If
Multipath TCP is not supported by the kernel or the remote host,
the connection will silently fall back to TCP. To test whether a
particular connection is using Multipath TCP, use the TCPConn.MultipathTCP method.
In a future Go release we may enable Multipath TCP by default on systems that support it.
The new ResponseController.EnableFullDuplex method allows server handlers to concurrently read from an HTTP/1
request body while writing the response. Normally, the HTTP/1 server
automatically consumes any remaining request body before starting to
write the response, to avoid deadlocking clients which attempt to
write a complete request before reading the response. The EnableFullDuplex method disables this behavior.
The new ErrSchemeMismatch error is returned by Client and Transport when the server responds to an HTTPS request with an HTTP response.
The net/http package now supports errors.ErrUnsupported,
in that the expression errors.Is(http.ErrNotSupported, errors.ErrUnsupported) will return true.
Programs may now pass an empty time.Time value to
the Chtimes function
to leave either the access time or the modification time unchanged.
On Windows the File.Chdir method
now changes the current directory to the file, rather than
always returning an error.
On Unix systems, if a non-blocking descriptor is passed
to NewFile, calling
the File.Fd method
will now return a non-blocking descriptor. Previously the
descriptor was converted to blocking mode.
On Windows calling Truncate on a
non-existent file used to create an empty file. It now returns
an error indicating that the file does not exist.
On Windows calling TempDir now uses
GetTempPath2W when available, instead of GetTempPathW. The
new behavior is a security hardening measure that prevents
temporary files created by processes running as SYSTEM to
be accessed by non-SYSTEM processes.
On Windows the os package now supports working with files whose names, stored as UTF-16, can’t be represented as valid UTF-8.
On Windows Lstat now resolves
symbolic links for paths ending with a path separator, consistent with its
behavior on POSIX platforms.
The implementation of the io/fs.DirEntry interface returned by the ReadDir function and
the File.ReadDir method now implements a String method that calls io/fs.FormatDirEntry.
The implementation of the io/fs.FS interface returned by
the DirFS function now implements
the io/fs.ReadFileFS and
the io/fs.ReadDirFS interfaces.
The implementation of the io/fs.DirEntry interface passed to the function argument of WalkDir now implements a String method that calls io/fs.FormatDirEntry.
In Go 1.21, ValueOf no longer forces its argument to be allocated on the heap, allowing
a Value ’s content to be allocated on the stack. Most
operations on a Value also allow the underlying value
to be stack allocated.
The new Value method Value.Clear clears the contents of a map or zeros the contents of a slice.
This corresponds to the new clear built-in added to the language.
The SliceHeader and StringHeader types are now deprecated. In new code
prefer unsafe.Slice, unsafe.SliceData, unsafe.String,
or unsafe.StringData.
Regexp now defines MarshalText and UnmarshalText methods. These implement encoding.TextMarshaler and encoding.TextUnmarshaler and will be used by packages such as encoding/json.
Textual stack traces produced by Go programs, such as those
produced when crashing, calling runtime.Stack, or
collecting a goroutine profile with debug=2, now
include the IDs of the goroutines that created each goroutine in
the stack trace.
Crashing Go applications can now opt-in to Windows Error Reporting (WER) by setting the environment variable GOTRACEBACK=wer or calling debug.SetTraceback("wer") before the crash. Other than enabling WER, the runtime will behave as with GOTRACEBACK=crash.
On non-Windows systems, GOTRACEBACK=wer is ignored.
GODEBUG=cgocheck=2, a thorough checker of cgo pointer passing rules,
is no longer available as a debug option.
Instead, it is available as an experiment using GOEXPERIMENT=cgocheck2.
In particular this means that this mode has to be selected at build time instead of startup time.
GODEBUG=cgocheck=1 is still available (and is still the default).
A new type Pinner has been added to the runtime
package. Pinner s may be used to “pin” Go memory
such that it may be used more freely by non-Go code. For instance,
passing Go values that reference pinned Go memory to C code is
now allowed. Previously, passing any such nested reference was
disallowed by the cgo pointer passing rules. See the docs for more details.
A few previously-internal GC metrics, such as live heap size, are
now available. GOGC and GOMEMLIMIT are also now
available as metrics.
Collecting traces on amd64 and arm64 now incurs a substantially smaller CPU cost: up to a 10x improvement over the previous release.
Traces now contain explicit stop-the-world events for every reason the Go runtime might stop-the-world, not just garbage collection.
The new OnceFunc, OnceValue, and OnceValues functions capture a common use of Once to
lazily initialize a value on first use.
On Windows the Fchdir function
now changes the current directory to its argument, rather than
always returning an error.
On FreeBSD SysProcAttr has a new field Jail that may be used to put the
newly created process in a jailed environment.
On Windows the syscall package now supports working with files whose
names, stored as UTF-16, can’t be represented as valid UTF-8.
The UTF16ToString and UTF16FromString functions now convert between UTF-16 data and WTF-8 strings.
This is backward compatible as WTF-8 is a superset of the UTF-8
format that was used in earlier releases.
Several error values match the new errors.ErrUnsupported,
such that errors.Is(err, errors.ErrUnsupported) returns true.
ENOSYS ENOTSUP EOPNOTSUPP EPLAN9 (Plan 9 only) ERROR_CALL_NOT_IMPLEMENTED (Windows only) ERROR_NOT_SUPPORTED (Windows only) EWINDOWS (Windows only)
The new -test.fullpath option will print full path
names in test log messages, rather than just base names.
The new Testing function reports whether the program is a test created by go test.
Calling [Open](https://go.dev/pkg/testing/fstest/MapFS.Open).[Stat](https://go.dev/pkg/io/fs/#File.Stat) will return a type that now implements a String method that calls io/fs.FormatFileInfo.
The unicode package and
associated support throughout the system has been upgraded to Unicode 15.0.0.
As announced in the Go 1.20 release notes, Go 1.21 requires macOS 10.15 Catalina or later; support for previous versions has been discontinued.
As announced in the Go 1.20 release notes, Go 1.21 requires at least Windows 10 or Windows Server 2016; support for previous versions has been discontinued.
When building the Go distribution with GOARCH=arm when not running
on an ARM system (that is, when building a cross-compiler to ARM), the
default value for the GOARM environment variable is now always set
to 7.
Previously the default depended on characteristics of the build
system.
When not building a cross-compiler, the default value is determined by examining the build system. That was true before and remains true in Go 1.21. What has changed is the behavior when building a cross-compiler.
The new go:wasmimport directive can now be used in Go programs
to import functions from the WebAssembly host.
The Go scheduler now interacts much more efficiently with the JavaScript event loop, especially in applications that block frequently on asynchronous events.
Go 1.21 adds an experimental port to the WebAssembly System Interface (WASI), Preview 1
( GOOS=wasip1, GOARCH=wasm).
As a result of the addition of the new GOOS value
“ wasip1 ”, Go files named *_wasip1.go will now be ignored
by Go tools except when that GOOS value is being
used.
If you have existing filenames matching that pattern, you will
need to rename them.
On Linux, GOPPC64=power10 now generates PC-relative instructions, prefixed
instructions, and other new Power10 instructions. On AIX, GOPPC64=power10 generates Power10 instructions, but does not generate PC-relative instructions.
When building position-independent binaries for GOPPC64=power10 GOOS=linux GOARCH=ppc64le, users can expect reduced binary
sizes in most cases, in some cases 3.5%. Position-independent binaries are built for
ppc64le with the following -buildmode values: c-archive, c-shared, shared, pie, plugin.
The linux/loong64 port now supports -buildmode=c-archive, -buildmode=c-shared and -buildmode=pie.
Update Aug 1, 2023 tracked by Updatify
go1.20.7 (released 2023-08-01) includes a security fix to the crypto/tls package, as well as bug fixes to the assembler and the compiler. See the Go 1.20.7 milestone on our issue tracker for details.
Update Aug 1, 2023 tracked by Updatify
go1.19.12 (released 2023-08-01) includes a security fix to the crypto/tls package, as well as bug fixes to the assembler and the compiler. See the Go 1.19.12 milestone on our issue tracker for details.
Update Jul 11, 2023 tracked by Updatify
go1.20.6 (released 2023-07-11) includes a security fix to the net/http package, as well as bug fixes to the compiler, cgo, the cover tool, the go command, the runtime, and the crypto/ecdsa, go/build, go/printer, net/mail, and text/template packages. See the Go 1.20.6 milestone on our issue tracker for details.
Update Jul 11, 2023 tracked by Updatify
go1.19.11 (released 2023-07-11) includes a security fix to the net/http package, as well as bug fixes to cgo, the cover tool, the go command, the runtime, and the go/printer package. See the Go 1.19.11 milestone on our issue tracker for details.
Update Jun 6, 2023 tracked by Updatify
go1.20.5 (released 2023-06-06) includes four security fixes to the cmd/go and runtime packages, as well as bug fixes to the compiler, the go command, the runtime, and the crypto/rsa, net, and os packages. See the Go 1.20.5 milestone on our issue tracker for details.
Update Jun 6, 2023 tracked by Updatify
go1.19.10 (released 2023-06-06) includes four security fixes to the cmd/go and runtime packages, as well as bug fixes to the compiler, the go command, and the runtime. See the Go 1.19.10 milestone on our issue tracker for details.
Update May 2, 2023 tracked by Updatify
go1.20.4 (released 2023-05-02) includes three security fixes to the html/template package, as well as bug fixes to the compiler, the runtime, and the crypto/subtle, crypto/tls, net/http, and syscall packages. See the Go 1.20.4 milestone on our issue tracker for details.
Update May 2, 2023 tracked by Updatify
go1.19.9 (released 2023-05-02) includes three security fixes to the html/template package, as well as bug fixes to the compiler, the runtime, and the crypto/tls and syscall packages. See the Go 1.19.9 milestone on our issue tracker for details.
Update Apr 4, 2023 tracked by Updatify
go1.20.3 (released 2023-04-04) includes security fixes to the go/parser, html/template, mime/multipart, net/http, and net/textproto packages, as well as bug fixes to the compiler, the linker, the runtime, and the time package. See the Go 1.20.3 milestone on our issue tracker for details.
Update Apr 4, 2023 tracked by Updatify
go1.19.8 (released 2023-04-04) includes security fixes to the go/parser, html/template, mime/multipart, net/http, and net/textproto packages, as well as bug fixes to the linker, the runtime, and the time package. See the Go 1.19.8 milestone on our issue tracker for details.
Update Mar 7, 2023 tracked by Updatify
go1.20.2 (released 2023-03-07) includes a security fix to the crypto/elliptic package, as well as bug fixes to the compiler, the covdata command, the linker, the runtime, and the crypto/ecdh, crypto/rsa, crypto/x509, os, and syscall packages. See the Go 1.20.2 milestone on our issue tracker for details.
Update Mar 7, 2023 tracked by Updatify
go1.19.7 (released 2023-03-07) includes a security fix to the crypto/elliptic package, as well as bug fixes to the linker, the runtime, and the crypto/x509 and syscall packages. See the Go 1.19.7 milestone on our issue tracker for details.
Update Feb 14, 2023 tracked by Updatify
go1.20.1 (released 2023-02-14) includes security fixes to the crypto/tls, mime/multipart, net/http, and path/filepath packages, as well as bug fixes to the compiler, the go command, the linker, the runtime, and the time package. See the Go 1.20.1 milestone on our issue tracker for details.
Update Feb 14, 2023 tracked by Updatify
go1.19.6 (released 2023-02-14) includes security fixes to the crypto/tls, mime/multipart, net/http, and path/filepath packages, as well as bug fixes to the go command, the linker, the runtime, and the crypto/x509, net/http, and time packages. See the Go 1.19.6 milestone on our issue tracker for details.
Update Feb 1, 2023 tracked by Updatify
The latest Go release, version 1.20, arrives six months after Go 1.19. Most of its changes are in the implementation of the toolchain, runtime, and libraries. As always, the release maintains the Go 1 promise of compatibility. We expect almost all Go programs to continue to compile and run as before.
Go 1.20 includes four changes to the language.
Go 1.17 added conversions from slice to an array pointer.
Go 1.20 extends this to allow conversions from a slice to an array:
given a slice x, [4]byte(x) can now be written
instead of *(*[4]byte)(x).
The unsafe package defines
three new functions SliceData, String, and StringData.
Along with Go 1.17’s Slice, these functions now provide the complete ability to
construct and deconstruct slice and string values, without depending on their exact representation.
The specification now defines that struct values are compared one field at a time, considering fields in the order they appear in the struct type definition, and stopping at the first mismatch. The specification could previously have been read as if all fields needed to be compared beyond the first mismatch. Similarly, the specification now defines that array values are compared one element at a time, in increasing index order. In both cases, the difference affects whether certain comparisons must panic. Existing programs are unchanged: the new spec wording describes what the implementations have always done.
Comparable types (such as ordinary interfaces)
may now satisfy comparable constraints, even if the type arguments
are not strictly comparable (comparison may panic at runtime).
This makes it possible to instantiate a type parameter constrained by comparable (e.g., a type parameter for a user-defined generic map key) with a non-strictly comparable type argument
such as an interface type, or a composite type containing an interface type.
Go 1.20 is the last release that will run on any release of Windows 7, 8, Server 2008 and Server 2012. Go 1.21 will require at least Windows 10 or Server 2016.
Go 1.20 is the last release that will run on macOS 10.13 High Sierra or 10.14 Mojave. Go 1.21 will require macOS 10.15 Catalina or later.
Go 1.20 adds experimental support for FreeBSD on RISC-V ( GOOS=freebsd, GOARCH=riscv64).
The directory $GOROOT/pkg no longer stores
pre-compiled package archives for the standard library: go install no longer writes them,
the go build no longer checks for them,
and the Go distribution no longer ships them.
Instead, packages in the standard library are built as needed
and cached in the build cache, just like packages outside GOROOT.
This change reduces the size of the Go distribution and also
avoids C toolchain skew for packages that use cgo.
The implementation of go test -json has been improved to make it more robust.
Programs that run go test -json do not need any updates.
Programs that invoke go tool test2json directly should now run the test binary with -v=test2json (for example, go test -v=test2json or ./pkg.test -test.v=test2json)
instead of plain -v.
A related change to go test -json is the addition of an event with Action set to start at the beginning of each test program’s execution.
When running multiple tests using the go command,
these start events are guaranteed to be emitted in the same order as
the packages named on the command line.
The go command now defines
architecture feature build tags, such as amd64.v2,
to allow selecting a package implementation file based on the presence
or absence of a particular architecture feature.
See go help buildconstraint for details.
The go subcommands now accept -C <dir> to change directory to <dir>
before performing the command, which may be useful for scripts that need to
execute commands in multiple different modules.
The go build and go test commands no longer accept the -i flag,
which has been deprecated since Go 1.16.
The go generate command now accepts -skip <pattern> to skip //go:generate directives
matching <pattern>.
The go test command now accepts -skip <pattern> to skip tests, subtests, or examples
matching <pattern>.
When the main module is located within GOPATH/src, go install no longer installs libraries for
non- main packages to GOPATH/pkg,
and go list no longer reports a Target field for such packages. (In module mode, compiled packages are stored in the build cache only, but a bug had caused
the GOPATH install targets to unexpectedly remain in effect.)
The go build, go install,
and other build-related commands now support a -pgo flag that enables
profile-guided optimization, which is described in more detail in the Compiler section below.
The -pgo flag specifies the file path of the profile.
Specifying -pgo=auto causes the go command to search
for a file named default.pgo in the main package’s directory and
use it if present.
This mode currently requires a single main package to be specified on the
command line, but we plan to lift this restriction in a future release.
Specifying -pgo=off turns off profile-guided optimization.
The go build, go install,
and other build-related commands now support a -cover flag that builds the specified target with code coverage instrumentation.
This is described in more detail in the Cover section below.
go version
The go version -m command
now supports reading more types of Go binaries, most notably, Windows DLLs
built with go build -buildmode=c-shared and Linux binaries without execute permission.
The go command now disables cgo by default
on systems without a C toolchain.
More specifically, when the CGO_ENABLED environment variable is unset,
the CC environment variable is unset,
and the default C compiler (typically clang or gcc)
is not found in the path, CGO_ENABLED defaults to 0.
As always, you can override the default by setting CGO_ENABLED explicitly.
The most important effect of the default change is that when Go is installed on a system without a C compiler, it will now use pure Go builds for packages in the standard library that use cgo, instead of using pre-distributed package archives (which have been removed, as noted above) or attempting to use cgo and failing. This makes Go work better in some minimal container environments as well as on macOS, where pre-distributed package archives have not been used for cgo-based packages since Go 1.16.
The packages in the standard library that use cgo are net, os/user, and plugin.
On macOS, the net and os/user packages have been rewritten not to use cgo:
the same code is now used for cgo and non-cgo builds as well as cross-compiled builds.
On Windows, the net and os/user packages have never used cgo.
On other systems, builds with cgo disabled will use a pure Go version of these packages.
A consequence is that, on macOS, if Go code that uses
the net package is built
with -buildmode=c-archive, linking the resulting
archive into a C program requires passing -lresolv when
linking the C code.
On macOS, the race detector has been rewritten not to use cgo: race-detector-enabled programs can be built and run without Xcode. On Linux and other Unix systems, and on Windows, a host C toolchain is required to use the race detector.
Go 1.20 supports collecting code coverage profiles for programs (applications and integration tests), as opposed to just unit tests.
To collect coverage data for a program, build it with go build ’s -cover flag, then run the resulting
binary with the environment variable GOCOVERDIR set
to an output directory for coverage profiles.
See the ‘coverage for integration tests’ landing page for more on how to get started.
For details on the design and implementation, see the proposal.
The vet tool now reports references to loop variables following
a call to T.Parallel() within subtest function bodies. Such references may observe the value of the
variable from a different iteration (typically causing test cases to be
skipped) or an invalid state due to unsynchronized concurrent access.
The tool also detects reference mistakes in more places. Previously it would only consider the last statement of the loop body, but now it recursively inspects the last statements within if, switch, and select statements.
The vet tool now reports use of the time format 2006-02-01 (yyyy-dd-mm)
with Time.Format and time.Parse.
This format does not appear in common date standards, but is frequently
used by mistake when attempting to use the ISO 8601 date format
(yyyy-mm-dd).
Some of the garbage collector’s internal data structures were reorganized to be both more space and CPU efficient. This change reduces memory overheads and improves overall CPU performance by up to 2%.
The garbage collector behaves less erratically with respect to goroutine assists in some circumstances.
Go 1.20 adds a new runtime/coverage package
containing APIs for writing coverage profile data at
runtime from long-running and/or server programs that
do not terminate via os.Exit().
Go 1.20 adds preview support for profile-guided optimization (PGO).
PGO enables the toolchain to perform application- and workload-specific
optimizations based on run-time profile information.
Currently, the compiler supports pprof CPU profiles, which can be collected
through usual means, such as the runtime/pprof or net/http/pprof packages.
To enable PGO, pass the path of a pprof profile file via the -pgo flag to go build,
as mentioned above.
Go 1.20 uses PGO to more aggressively inline functions at hot call sites.
Benchmarks for a representative set of Go programs show enabling
profile-guided inlining optimization improves performance about 3–4%.
See the PGO user guide for detailed documentation.
We plan to add more profile-guided optimizations in future releases.
Note that profile-guided optimization is a preview, so please use it
with appropriate caution.
The Go 1.20 compiler upgraded its front-end to use a new way of handling the compiler’s internal data, which fixes several generic-types issues and enables type declarations within generic functions and methods.
The compiler now rejects anonymous interface cycles with a compiler error by default. These arise from tricky uses of embedded interfaces and have always had subtle correctness issues, yet we have no evidence that they’re actually used in practice. Assuming no reports from users adversely affected by this change, we plan to update the language specification for Go 1.22 to formally disallow them so tools authors can stop supporting them too.
Go 1.18 and 1.19 saw regressions in build speed, largely due to the addition of support for generics and follow-on work. Go 1.20 improves build speeds by up to 10%, bringing it back in line with Go 1.17. Relative to Go 1.19, generated code performance is also generally slightly improved.
On Linux, the linker now selects the dynamic interpreter for glibc or musl at link time.
On Windows, the Go linker now supports modern LLVM-based C toolchains.
Go 1.20 uses go: and type: prefixes for compiler-generated
symbols rather than go. and type..
This avoids confusion for user packages whose name starts with go..
The debug/gosym package understands
this new naming convention for binaries built with Go 1.20 and newer.
When building a Go release from source and GOROOT_BOOTSTRAP is not set,
previous versions of Go looked for a Go 1.4 or later bootstrap toolchain in the directory $HOME/go1.4 ( %HOMEDRIVE%%HOMEPATH%\go1.4 on Windows).
Go 1.18 and Go 1.19 looked first for $HOME/go1.17 or $HOME/sdk/go1.17 before falling back to $HOME/go1.4,
in anticipation of requiring Go 1.17 for use when bootstrapping Go 1.20.
Go 1.20 does require a Go 1.17 release for bootstrapping, but we realized that we should
adopt the latest point release of the bootstrap toolchain, so it requires Go 1.17.13.
Go 1.20 looks for $HOME/go1.17.13 or $HOME/sdk/go1.17.13 before falling back to $HOME/go1.4 (to support systems that hard-coded the path $HOME/go1.4 but have installed
a newer Go toolchain there).
In the future, we plan to move the bootstrap toolchain forward approximately once a year,
and in particular we expect that Go 1.22 will require the final point release of Go 1.20 for bootstrap.
Go 1.20 adds a new crypto/ecdh package
to provide explicit support for Elliptic Curve Diffie-Hellman key exchanges
over NIST curves and Curve25519.
Programs should use crypto/ecdh instead of the lower-level functionality in crypto/elliptic for ECDH, and
third-party modules for more advanced use cases.
Go 1.20 expands support for error wrapping to permit an error to wrap multiple other errors.
An error e can wrap more than one error by providing
an Unwrap method that returns a []error.
The errors.Is and errors.As functions
have been updated to inspect multiply wrapped errors.
The fmt.Errorf function
now supports multiple occurrences of the %w format verb,
which will cause it to return an error that wraps all of those error operands.
The new function errors.Join returns an error wrapping a list of errors.
The new "net/http".ResponseController type provides access to extended per-request functionality not handled by the "net/http".ResponseWriter interface.
Previously, we have added new per-request functionality by defining optional
interfaces which a ResponseWriter can implement, such as Flusher. These interfaces
are not discoverable and clumsy to use.
The ResponseController type provides a clearer, more discoverable way
to add per-handler controls. Two such controls also added in Go 1.20 are SetReadDeadline and SetWriteDeadline, which allow setting
per-request read and write deadlines. For example:
func RequestHandler(w ResponseWriter, r *Request) {
rc := http.NewResponseController(w)
rc.SetWriteDeadline(time.Time{}) // disable Server.WriteTimeout when sending a large response
io.Copy(w, bigData)
}
The httputil.ReverseProxy forwarding proxy includes a new Rewrite hook function, superseding the
previous Director hook.
The Rewrite hook accepts a ProxyRequest parameter,
which includes both the inbound request received by the proxy and the outbound
request that it will send.
Unlike Director hooks, which only operate on the outbound request,
this permits Rewrite hooks to avoid certain scenarios where
a malicious inbound request may cause headers added by the hook
to be removed before forwarding.
See issue #50580.
The ProxyRequest.SetURL method routes the outbound request to a provided destination
and supersedes the NewSingleHostReverseProxy function.
Unlike NewSingleHostReverseProxy, SetURL also sets the Host header of the outbound request.
The ProxyRequest.SetXForwarded method sets the X-Forwarded-For, X-Forwarded-Host,
and X-Forwarded-Proto headers of the outbound request.
When using a Rewrite, these headers are not added by default.
An example of a Rewrite hook using these features is:
proxyHandler := &httputil.ReverseProxy{
Rewrite: func(r *httputil.ProxyRequest) {
r.SetURL(outboundURL) // Forward request to outboundURL.
r.SetXForwarded() // Set X-Forwarded-* headers.
r.Out.Header.Set("X-Additional-Header", "header set by the proxy")
},
}
ReverseProxy no longer adds a User-Agent header
to forwarded requests when the incoming request does not have one.
As always, there are various minor changes and updates to the library, made with the Go 1 promise of compatibility in mind. There are also various performance improvements, not enumerated here.
When the GODEBUG=tarinsecurepath=0 environment variable is set, Reader.Next method
will now return the error ErrInsecurePath for an entry with a file name that is an absolute path,
refers to a location outside the current directory, contains invalid
characters, or (on Windows) is a reserved name such as NUL.
A future version of Go may disable insecure paths by default.
When the GODEBUG=zipinsecurepath=0 environment variable is set, NewReader will now return the error ErrInsecurePath when opening an archive which contains any file name that is an absolute path,
refers to a location outside the current directory, contains invalid
characters, or (on Windows) is a reserved names such as NUL.
A future version of Go may disable insecure paths by default.
Reading from a directory file that contains file data will now return an error. The zip specification does not permit directory files to contain file data, so this change only affects reading from invalid archives.
The new CutPrefix and CutSuffix functions
are like TrimPrefix and TrimSuffix but also report whether the string was trimmed.
The new Clone function
allocates a copy of a byte slice.
The new WithCancelCause function
provides a way to cancel a context with a given error.
That error can be retrieved by calling the new Cause function.
When using supported curves, all operations are now implemented in constant time. This led to an increase in CPU time between 5% and 30%, mostly affecting P-384 and P-521.
The new PrivateKey.ECDH method
converts an ecdsa.PrivateKey to an ecdh.PrivateKey.
The PrivateKey.Sign method
and the VerifyWithOptions function
now support signing pre-hashed messages with Ed25519ph,
indicated by an Options.HashFunc that returns crypto.SHA512.
They also now support Ed25519ctx and Ed25519ph with context,
indicated by setting the new Options.Context field.
The new field OAEPOptions.MGFHash allows configuring the MGF1 hash separately for OAEP decryption.
crypto/rsa now uses a new, safer, constant-time backend. This causes a CPU
runtime increase for decryption operations between approximately 15%
(RSA-2048 on amd64) and 45% (RSA-4096 on arm64), and more on 32-bit architectures.
Encryption operations are approximately 20x slower than before (but still 5-10x faster than decryption).
Performance is expected to improve in future releases.
Programs must not modify or manually generate the fields of PrecomputedValues.
The new function XORBytes XORs two byte slices together.
Parsed certificates are now shared across all clients actively using that certificate. The memory savings can be significant in programs that make many concurrent connections to a server or collection of servers sharing any part of their certificate chains.
For a handshake failure due to a certificate verification failure,
the TLS client and server now return an error of the new type CertificateVerificationError,
which includes the presented certificates.
ParsePKCS8PrivateKey and MarshalPKCS8PrivateKey now support keys of type *crypto/ecdh.PrivateKey. ParsePKIXPublicKey and MarshalPKIXPublicKey now support keys of type *crypto/ecdh.PublicKey.
Parsing NIST curve keys still returns values of type *ecdsa.PublicKey and *ecdsa.PrivateKey.
Use their new ECDH methods to convert to the crypto/ecdh types.
The new SetFallbackRoots function allows a program to define a set of fallback root certificates in case an
operating system verifier or standard platform root bundle is unavailable at runtime.
It will most commonly be used with a new package, golang.org/x/crypto/x509roots/fallback,
which will provide an up to date root bundle.
Attempts to read from a SHT_NOBITS section using Section.Data or the reader returned by Section.Open now return an error.
Additional R_LARCH_* constants are defined for use with LoongArch systems.
Additional R_PPC64_* constants are defined for use with PPC64 ELFv2 relocations.
The constant value for R_PPC64_SECTOFF_LO_DS is corrected, from 61 to 62.
Due to a change of Go’s symbol naming conventions, tools that
process Go binaries should use Go 1.20’s debug/gosym package to
transparently handle both old and new binaries.
Additional IMAGE_FILE_MACHINE_RISCV* constants are defined for use with RISC-V systems.
The ReadVarint and ReadUvarint functions will now return io.ErrUnexpectedEOF after reading a partial value,
rather than io.EOF.
The new Encoder.Close method
can be used to check for unclosed elements when finished encoding.
The decoder now rejects element and attribute names with more than one colon,
such as <a:b:c>,
as well as namespaces that resolve to an empty string, such as xmlns:a="".
The decoder now rejects elements that use different namespace prefixes in the opening and closing tag, even if those prefixes both denote the same namespace.
The new Join function returns an error wrapping a list of errors.
The Errorf function supports multiple occurrences of
the %w format verb, returning an error that unwraps to the list of all arguments to %w.
The new FormatString function recovers the
formatting directive corresponding to a State,
which can be useful in Formatter.
implementations.
The new RangeStmt.Range field
records the position of the range keyword in a range statement.
The new File.FileStart and File.FileEnd fields
record the position of the start and end of the entire source file.
The new FileSet.RemoveFile method
removes a file from a FileSet.
Long-running programs can use this to release memory associated
with files they no longer need.
The new Satisfies function reports
whether a type satisfies a constraint.
This change aligns with the new language semantics that distinguish satisfying a constraint from implementing an interface.
Go 1.20.3 and later disallow actions in ECMAScript 6 template literals. This behavior can be reverted by the GODEBUG=jstmpllitinterp=1 setting.
The new OffsetWriter wraps an underlying WriterAt and provides Seek, Write, and WriteAt methods
that adjust their effective file offset position by a fixed amount.
The new error SkipAll terminates a WalkDir immediately but successfully.
The math/big package’s wide scope and input-dependent timing make it ill-suited for implementing cryptography. The cryptography packages in the standard library no longer call non-trivial Int methods on attacker-controlled inputs. In the future, the determination of whether a bug in math/big is considered a security vulnerability will depend on its wider impact on the standard library.
The math/rand package now automatically seeds
the global random number generator
(used by top-level functions like Float64 and Int) with a random value,
and the top-level Seed function has been deprecated.
Programs that need a reproducible sequence of random numbers
should prefer to allocate their own random source, using rand.New(rand.NewSource(seed)).
Programs that need the earlier consistent global seeding behavior can set GODEBUG=randautoseed=0 in their environment.
The top-level Read function has been deprecated.
In almost all cases, crypto/rand.Read is more appropriate.
The ParseMediaType function now allows duplicate parameter names,
so long as the values of the names are the same.
Methods of the Reader type now wrap errors
returned by the underlying io.Reader.
In Go 1.19.8 and later, this package sets limits the size
of the MIME data it processes to protect against malicious inputs. Reader.NextPart and Reader.NextRawPart limit the
number of headers in a part to 10000 and Reader.ReadForm limits
the total number of headers in all FileHeaders to 10000.
These limits may be adjusted with the GODEBUG=multipartmaxheaders setting. Reader.ReadForm further limits the number of parts in a form to 1000.
This limit may be adjusted with the GODEBUG=multipartmaxparts setting.
The LookupCNAME function now consistently returns the contents
of a CNAME record when one exists. Previously on Unix systems and
when using the pure Go resolver, LookupCNAME would return an error
if a CNAME record referred to a name that with no A, AAAA, or CNAME record. This change modifies LookupCNAME to match the previous behavior on Windows,
allowing LookupCNAME to succeed whenever a CNAME exists.
Interface.Flags now includes the new flag FlagRunning,
indicating an operationally active interface. An interface which is administratively
configured but not active (for example, because the network cable is not connected)
will have FlagUp set but not FlagRunning.
The new Dialer.ControlContext field contains a callback function
similar to the existing Dialer.Control hook, that additionally
accepts the dial context as a parameter. Control is ignored when ControlContext is not nil.
The Go DNS resolver recognizes the trust-ad resolver option.
When options trust-ad is set in resolv.conf,
the Go resolver will set the AD bit in DNS queries. The resolver does not
make use of the AD bit in responses.
DNS resolution will detect changes to /etc/nsswitch.conf and reload the file when it changes. Checks are made at most once every
five seconds, matching the previous handling of /etc/hosts and /etc/resolv.conf.
The ResponseWriter.WriteHeader function now supports sending 1xx status codes.
The new Server.DisableGeneralOptionsHandler configuration setting
allows disabling the default OPTIONS * handler.
The new Transport.OnProxyConnectResponse hook is called
when a Transport receives an HTTP response from a proxy
for a CONNECT request.
The HTTP server now accepts HEAD requests containing a body, rather than rejecting them as invalid.
HTTP/2 stream errors returned by net/http functions may be converted
to a golang.org/x/net/http2.StreamError using errors.As.
Leading and trailing spaces are trimmed from cookie names, rather than being rejected as invalid. For example, a cookie setting of “name =value” is now accepted as setting the cookie “name”.
A Cookie with an empty Expires field is now considered valid. Cookie.Valid only checks Expires when it is set.
The new IPv6LinkLocalAllRouters and IPv6Loopback functions
are the net/netip equivalents of net.IPv6loopback and net.IPv6linklocalallrouters.
On Windows, the name NUL is no longer treated as a special case in Mkdir and Stat.
On Windows, File.Stat now uses the file handle to retrieve attributes when the file is a directory.
Previously it would use the path passed to Open, which may no longer be the file
represented by the file handle if the file has been moved or replaced.
This change modifies Open to open directories without the FILE_SHARE_DELETE access, which match the behavior of regular files.
On Windows, File.Seek now supports
seeking to the beginning of a directory.
The new Cmd fields Cancel and WaitDelay specify the behavior of the Cmd when its associated Context is canceled or its process exits with I/O pipes still
held open by a child process.
The new error SkipAll terminates a Walk immediately but successfully.
The new IsLocal function reports whether a path is
lexically local to a directory.
For example, if IsLocal(p) is true,
then Open(p) will refer to a file that is lexically
within the subtree rooted at the current directory.
The new Value.Comparable and Value.Equal methods
can be used to compare two Value s for equality. Comparable reports whether Equal is a valid operation for a given Value receiver.
The new Value.Grow method
extends a slice to guarantee space for another n elements.
The new Value.SetZero method
sets a value to be the zero value for its type.
Go 1.18 introduced Value.SetIterKey and Value.SetIterValue methods.
These are optimizations: v.SetIterKey(it) is meant to be equivalent to v.Set(it.Key()).
The implementations incorrectly omitted a check for use of unexported fields that was present in the unoptimized forms.
Go 1.20 corrects these methods to include the unexported field check.
Go 1.19.2 and Go 1.18.7 included a security fix to the regular expression parser,
making it reject very large expressions that would consume too much memory.
Because Go patch releases do not introduce new API,
the parser returned syntax.ErrInternalError in this case.
Go 1.20 adds a more specific error, syntax.ErrLarge,
which the parser now returns instead.
Go 1.20 adds new Incomplete marker type.
Code generated by cgo will use cgo.Incomplete to mark an incomplete C type.
Go 1.20 adds new supported metrics,
including the current GOMAXPROCS setting ( /sched/gomaxprocs:threads),
the number of cgo calls executed ( /cgo/go-to-c-calls:calls),
total mutex block time ( /sync/mutex/wait/total:seconds), and various measures of time
spent in garbage collection.
Time-based histogram metrics are now less precise, but take up much less memory.
Mutex profile samples are now pre-scaled, fixing an issue where old mutex profile samples would be scaled incorrectly if the sampling rate changed during execution.
Profiles collected on Windows now include memory mapping information that fixes symbolization issues for position-independent binaries.
The garbage collector’s background sweeper now yields less frequently, resulting in many fewer extraneous events in execution traces.
The new CutPrefix and CutSuffix functions
are like TrimPrefix and TrimSuffix but also report whether the string was trimmed.
The new Map methods Swap, CompareAndSwap, and CompareAndDelete allow existing map entries to be updated atomically.
On FreeBSD, compatibility shims needed for FreeBSD 11 and earlier have been removed.
On Linux, additional CLONE_* constants
are defined for use with the SysProcAttr.Cloneflags field.
On Linux, the new SysProcAttr.CgroupFD and SysProcAttr.UseCgroupFD fields
provide a way to place a child process into a specific cgroup.
The new method B.Elapsed reports the current elapsed time of the benchmark, which may be useful for
calculating rates to report with ReportMetric.
Calling T.Run from a function passed
to T.Cleanup was never well-defined, and will now panic.
The new time layout constants DateTime, DateOnly, and TimeOnly provide names for three of the most common layout strings used in a survey of public Go source code.
The new Time.Compare method
compares two times.
Parse now ignores sub-nanosecond precision in its input,
instead of reporting those digits as an error.
The Time.MarshalJSON method
is now more strict about adherence to RFC 3339.
The new AppendRune function appends the UTF-16 encoding of a given rune to a uint16 slice,
analogous to utf8.AppendRune.
Update Jan 10, 2023 tracked by Updatify
go1.19.5 (released 2023-01-10) includes fixes to the compiler, the linker, and the crypto/x509, net/http, sync/atomic, and syscall packages. See the Go 1.19.5 milestone on our issue tracker for details.
Update Jan 10, 2023 tracked by Updatify
go1.18.10 (released 2023-01-10) includes fixes to cgo, the compiler, the linker, and the crypto/x509, net/http, and syscall packages. See the Go 1.18.10 milestone on our issue tracker for details.
Update Dec 6, 2022 tracked by Updatify
go1.19.4 (released 2022-12-06) includes security fixes to the net/http and os packages, as well as bug fixes to the compiler, the runtime, and the crypto/x509, os/exec, and sync/atomic packages. See the Go 1.19.4 milestone on our issue tracker for details.
Update Dec 6, 2022 tracked by Updatify
go1.18.9 (released 2022-12-06) includes security fixes to the net/http and os packages, as well as bug fixes to cgo, the compiler, the runtime, and the crypto/x509 and os/exec packages. See the Go 1.18.9 milestone on our issue tracker for details.