Go 1.9 is not yet released. These are work-in-progress release notes. Go 1.9 is expected to be released in August 2017.
The latest Go release, version 1.9, arrives six months after Go 1.8 and is the tenth release in the Go 1.x series. There is one change to the language, adding support for type aliases. Most of the 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 release adds transparent monotonic time support, parallelizes compilation of functions within a package, better supports test helper functions, and includes a new bit manipulation package.
There is one change to the language. Go now supports type aliases to support gradual code repair while moving a type between packages. The type alias design document and an article on refactoring cover the problem in detail. In short, a type alias declaration has the form:
type T1 = T2
This declaration introduces an alias name T1—an
alternate spelling—for the type denoted by T2; that is,
both T1 and T2 denote the same type.
There are no new supported operating systems or processor architectures in this release.
Both GOARCH=ppc64 and GOARCH=ppc64le now
require at least Power8 support. In previous releases,
only GOARCH=ppc64le required Power8 and the big
endian ppc64 architecture supported older
hardware.
There are some instabilities on FreeBSD that are known but not understood. These can lead to program crashes in rare cases. See issue 15658. Any help in solving this FreeBSD-specific issue would be appreciated.
The Go compiler now supports compiling a package's functions in parallel, taking
advantage of multiple cores. This is in addition to the go command's
existing support for parallel compilation of separate packages.
Parallel compilation is on by default, but can be disabled by setting the
environment variable GO19CONCURRENTCOMPILATION to 0.
As always, the changes are so general and varied that precise statements about performance are difficult to make. Most programs should run a bit faster, due to speedups in the garbage collector, better generated code, and optimizations in the core library.
TODO: There have been significant optimizations bringing more than 10% improvements
to implementations in the
foo,
bar,
and
quux
packages.
TODO(austin): give update.
The time package now transparently
tracks monotonic time in each Time
value, making computing durations between two Time values
a safe operation in the presence of wall clock adjustments.
See the package docs and
design document
for details.
Go 1.9 includes a new package,
math/bits, with optimized
implementations for manipulating bits. On most architectures
functions in this package are additionally recognized by the
compiler and treated as intrinsics for additional performance.
The
new (*T).Helper
an (*B).Helper
methods mark the calling function as a test helper function. When
printing file and line information, that function will be skipped.
This permits writing test helper functions while still having useful
line numbers for users.
As always, there are various minor changes and updates to the library, made with the Go 1 promise of compatibility in mind.
TODO: https://golang.org/cl/39570: set utf-8 flag
TODO: https://golang.org/cl/36876: add BLAKE2b and BLAKE2s hash constants
TODO: https://golang.org/cl/38366: ARM assembly versions of encrypt, decrypt and expandKey
TODO: https://golang.org/cl/43852: use blocking getrandom call on Linux when supported
TODO: https://golang.org/cl/36093: load certs from env vars + extra locations
TODO: https://golang.org/cl/36900: support excluded domains in name constraints.
TODO: https://golang.org/cl/35476: proper prepared statement support in transactions
TODO: https://golang.org/cl/39031: support scanning into user defined string types
TODO: https://golang.org/cl/40694: allow using a single connection from the database
TODO: https://golang.org/cl/44017: heuristically handle both UNIX and Windows paths
TODO: https://golang.org/cl/38660: add NullBytes and NullRawValue for working with ASN.1 NULL
TODO: https://golang.org/cl/38634: add Encoding.WithPadding, StdPadding, NoPadding
TODO: https://golang.org/cl/39203: speedup decoding of maps by zeroing values
TODO: https://golang.org/cl/37051: support sharp flag for float and complex value printing
TODO: https://golang.org/cl/44291: make -I/-L options in cgo flags absolute
TODO: https://golang.org/cl/38356: add 128-bit FNV hash support
TODO: https://golang.org/cl/37880: panic if predefined escapers are found in pipelines during rewriting
TODO: https://golang.org/cl/40936: allow safe usage of predefined escapers in pipelines
TODO: https://golang.org/cl/36734: fix the overlap check in Rectangle.Intersect.
TODO: https://golang.org/cl/36732: tweak the YCbCr to RGBA conversion formula again.
TODO: https://golang.org/cl/34150: reduce memory allocs encoding images by reusing buffers
TODO: https://golang.org/cl/38271: decode Gray8 transparent images.
TODO: https://golang.org/cl/36487: add IsInt64/IsUint64 predicates
TODO: https://golang.org/cl/36315: added package for bit-level counting and manipulation
TODO: https://golang.org/cl/39223: add Size to FileHeader
TODO: https://golang.org/cl/32572: add Resolver.StrictErrors
TODO: https://golang.org/cl/37260: allow Resolver to use a custom dialer
TODO: https://golang.org/cl/37402: implement deadline functionality on Pipe
TODO: https://golang.org/cl/40510: don't enclose non-literal IPv6 addresses in square brackets
TODO: https://golang.org/cl/40512: validate network in Dial{,IP} and Listen{Packet,IP} for IP networks
TODO: https://golang.org/cl/35488: add support for socks5 proxy
TODO: https://golang.org/cl/38194: strip port from host in mux Handler
TODO: https://golang.org/cl/43231: for http2, use the priority write scheduler by default
TODO: https://golang.org/cl/40012: expose cgi env vars in request context
TODO: https://golang.org/cl/34639: add Client and Certificate to Server
TODO: https://golang.org/cl/38474: Create empty maps and slices as return type
TODO: https://golang.org/cl/37915: parse command line without shell32.dll
TODO: https://golang.org/cl/41830: do not report ModeDir for symlinks on windows
TODO: https://golang.org/cl/37586: remove duplicate environment variables in Cmd.Start
TODO: https://golang.org/cl/33713: add Go implementation of LookupGroup, LookupGroupId
TODO: https://golang.org/cl/37664: add non-cgo versions of Lookup, LookupId
TODO: https://golang.org/cl/38335: Add MakeMapWithSize for creating maps with size hint
TODO: https://golang.org/cl/29341: use cpuset_getaffinity for runtime.NumCPU() on FreeBSD
TODO: https://golang.org/cl/34937: make ReadMemStats STW for < 25µs
TODO: https://golang.org/cl/35710: make time correctly update on Wine
TODO: https://golang.org/cl/37233: use inlining tables to generate accurate tracebacks
TODO: https://golang.org/cl/37441: make complex division c99 compatible
TODO: https://golang.org/cl/37520: make runtime.GC() trigger a concurrent GC
TODO: https://golang.org/cl/37726: strongly encourage CallersFrames with the result of Callers
TODO: https://golang.org/cl/38403: reduce Windows timer resolution when idle
TODO: https://golang.org/cl/40810: make sweep trace events encompass entire sweep loop
TODO: https://golang.org/cl/43641: use pselect6 for usleep on linux/amd64 and linux/arm
TODO: https://golang.org/cl/34013: don't run a GC when setting SetGCPercent negative
TODO: https://golang.org/cl/39835: don't trigger a GC on SetGCPercent
TODO: https://golang.org/cl/34198: add definitions of profile label types
TODO: https://golang.org/cl/34310: make Mutex more fair
TODO: https://golang.org/cl/36617: import Map from x/sync/syncmap
TODO: https://golang.org/cl/36697: only call setgroups if we need to
TODO: https://golang.org/cl/37439: use CLONE_VFORK and CLONE_VM
TODO: https://golang.org/cl/37913: add Conn and RawConn interfaces
TODO: https://golang.org/cl/41195: add argument to list tests, benchmarks, and examples
TODO: https://golang.org/cl/39152: generate all possible int64, uint64 values
TODO: https://golang.org/cl/38420: fix handling of empty blocks
TODO: https://golang.org/cl/36615: add Duration.Truncate and Duration.Round