time: Ticker.Reset(0) deadlocks

[tfg13]

What version of Go are you using (go version)?

$ go version
go version go1.17.2 darwin/arm64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="arm64"
GOBIN=""
GOCACHE="/Users/XXXX/Library/Caches/go-build"
GOENV="/Users/XXXX/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="arm64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/XXXX/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/XXXX/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_arm64"
GOVCS=""
GOVERSION="go1.17.2"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/dev/null"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/ct/1_807xnx3yvbbym9xwypyc540000gn/T/go-build1490192283=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

https://play.golang.org/p/weOQpA3YuFD

What did you expect to see?

Either:

• panic the Reset call for setting duration to zero (this will panic in time.NewTicker, but does not in time.Reset)
• tick the channel as fast as possible (delay zero), lots of "tick" output in my example

What did you see instead?

The ticker fires exactly one more tick, then stops - the example deadlocks because nothing is running anymore.
For any Duration >0 the ticker does not stop ticking after one tick.

[seankhliao]

cc @rsc

[gopherbot]

Change https://golang.org/cl/361074 mentions this issue: time: make Ticker.Reset(0) panic

[bradfitz]

I suspect panicking will be too invasive of a change. I'm sure there's plenty of code in the wild that does some math to compute a duration for Reset and isn't careful about whether it's <= 0 when what the caller would instead want is "right away".

[zhouguangyuan0718]

I suspect panicking will be too invasive of a change. I'm sure there's plenty of code in the wild that does some math to compute a duration for Reset and isn't careful about whether it's <= 0 when what the caller would instead want is "right away".

But if we make it tick as fast as possible when period is 0. This change is invasive, too.
Is it a reasonable choice if we keep as it is, and make this behavior as a feature?

[bradfitz]

Oh, sorry, I read this too quickly about being about Timer.Reset.

[zhouguangyuan0718]

I sent the CL above to fix this bug by adding a check. If duration <= 0, it will panic.
https://go-review.googlesource.com/c/go/+/361074/

If it is the right way to fix it, could anyone review it continue and submit?
Thanks.