mirror of
https://github.com/golang/go
synced 2024-11-15 11:30:36 -07:00
453cbb8f67
Change-Id: Ifa5894c67a36eb2c101b23b85775a3702512ca79 Reviewed-on: https://go-review.googlesource.com/c/go/+/571796 Reviewed-by: Ian Lance Taylor <iant@google.com> Auto-Submit: Russ Cox <rsc@golang.org> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
31 lines
1.5 KiB
Markdown
31 lines
1.5 KiB
Markdown
### Timer changes
|
|
|
|
Go 1.23 makes two significant changes to the implementation of
|
|
[`time.Timer`](/pkg/time#Timer) and [`time.Ticker`](/pkg/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](/doc/godebug) [`asynctimerchan=1`](/pkg/time/#NewTimer)
|
|
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.
|