Go 1.18 is not yet released. These are work-in-progress release notes. Go 1.18 is expected to be released in February 2022.
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Go 1.18 is the last release that is supported on FreeBSD 11.x, which has already reached end-of-life. Go 1.19 will require FreeBSD 12.2+ or FreeBSD 13.0+. FreeBSD 13.0+ will require a kernel with the COMPAT_FREEBSD12 option set (this is the default).
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go
get
no longer builds or installs packages in
module-aware mode. go
get
is now dedicated to
adjusting dependencies in go.mod
. Effectively, the
-d
flag is always enabled. To install the latest version
of an executable outside the context of the current module, use
go
install
example.com/cmd@latest
. Any
version query
may be used instead of latest
. This form of go
install
was added in Go 1.16, so projects supporting older
versions may need to provide install instructions for both go
install
and go
get
. go
get
now reports an error when used outside a module, since there
is no go.mod
file to update. In GOPATH mode (with
GO111MODULE=off
), go
get
still builds
and installs packages, as before.
The go
command now embeds version control information in
binaries including the currently checked-out revision, commit time, and a
flag indicating whether edited or untracked files are present. Version
control information is embedded if the go
command is invoked in
a directory within a Git, Mercurial, Fossil, or Bazaar repository, and the
main
package and its containing main module are in the same
repository. This information may be omitted using the flag
-buildvcs=false
.
Additionally, the go
command embeds information about the build
including build and tool tags (set with -tags
), compiler,
assembler, and linker flags (like -gcflags
), whether cgo was
enabled, and if it was, the values of the cgo environment variables
(like CGO_CFLAGS
). This information may be omitted using the
flag -buildinfo=false
. Both VCS and build information may be
read together with module information using go
version
-m
file
or
runtime/debug.ReadBuildInfo
(for the currently running binary)
or the new debug/buildinfo
package.
If the main module's go.mod
file
specifies go
1.17
or higher, go
mod
download
without
arguments now downloads source code for only the modules
explicitly required in the main
module's go.mod
file. (In a go
1.17
or
higher module, that set already includes all dependencies needed to build the
packages and tests in the main module.)
To also download source code for transitive dependencies, use
go
mod
download
all
.
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gofmt
gofmt
now reads and formats input files concurrently, with a
memory limit proportional to GOMAXPROCS
. On a machine with
multiple CPUs, gofmt
should now be significantly faster.
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net/netip
package
The new net/netip
package defines a new IP address type, Addr
.
Compared to the existing
net.IP
type, the netip.Addr
type takes less
memory, is immutable, and is comparable so it supports ==
and can be used as a map key.
In addition to Addr
, the package defines
AddrPort
, representing
an IP and port, and
Prefix
, representing
a network CIDR prefix.
The net
package now has methods to send and receive UDP packets
using netip.Addr
values instead of the relatively heavy
*net.UDPAddr
values.
As always, there are various minor changes and updates to the library, made with the Go 1 promise of compatibility in mind.
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This new package provides access to module versions, version control
information, and build flags embedded in executable files built by
the go
command. The same information is also available via
runtime/debug.ReadBuildInfo
for the currently running binary and via go
version
-m
on the command line.
The Draw
and DrawMask
fallback implementations
(used when the arguments are not the most common image types) are now
faster when those arguments implement the optional
draw.RGBA64Image
and image.RGBA64Image
interfaces that were added in Go 1.17.
The new
Value.SetIterKey
and Value.SetIterValue
methods set a Value using a map iterator as the source. They are equivalent to
Value.Set(iter.Key())
and Value.Set(iter.Value())
but
do fewer allocations.
The new
Value.UnsafePointer
method returns the Value's value as an unsafe.Pointer
.
This allows callers to migrate from Value.UnsafeAddr
and Value.Pointer
to eliminate the need to perform uintptr to unsafe.Pointer conversions at the callsite (as unsafe.Pointer rules require).