Apologies, the cover tool calls it -mode but the go command calls it -covermode.
go test -covermode=atomic -rob On Sun, Oct 2, 2022 at 3:48 PM Shulhan <m.shul...@gmail.com> wrote: > On Sun, 2 Oct 2022 10:41:17 +1100 > Rob Pike <r...@golang.org> wrote: > > > When running coverage in a concurrent program, use the -mode=atomic > > flag to avoid data races in the counters. This unavoidably has a > > significant performance hit, but it should resolve this race. > > > > -rob > > > > This flag print "no test files" when running go test, > > $ GOEXPERIMENT=coverageredesign CGO_ENABLED=1 go test -mode=atomic > -race -coverprofile=cover.out ./lib/dns > ? github.com/shuLhan/share [no test files] > > Not sure I am using the flag correctly or not since I cannot find it in > the current documentation [1]. > > [1] https://pkg.go.dev/cmd/go > > > > > On Sun, Oct 2, 2022 at 5:10 AM Shulhan <m.shul...@gmail.com> wrote: > > > > > Hi gophers, > > > > > > The latest Go tip always fail with data race when running with -race > > > and -coverprofile options. > > > > > > Here is an example of data race output, > > > > > > ---- > > > $ CGO_ENABLED=1 go test -failfast -race -count=1 > > > -coverprofile=cover.out ./... > > > ... > > > ================== > > > WARNING: DATA RACE > > > Read at 0x000001e5f04c by main goroutine: > > > > > > > internal/coverage/encodecounter.(*CoverageDataWriter).writeCounters.func2() > > > /home/ms/opt/go/src/internal/coverage/encodecounter/encode.go:261 > > > +0x11c > > > runtime/coverage.(*emitState).VisitFuncs() > > > /home/ms/opt/go/src/runtime/coverage/emit.go:539 +0x6bc > > > internal/coverage/encodecounter.(*CoverageDataWriter).writeCounters() > > > /home/ms/opt/go/src/internal/coverage/encodecounter/encode.go:268 > > > +0x16f > > > internal/coverage/encodecounter.(*CoverageDataWriter).AppendSegment() > > > /home/ms/opt/go/src/internal/coverage/encodecounter/encode.go:175 > > > +0x8ea > > > internal/coverage/encodecounter.(*CoverageDataWriter).Write() > > > /home/ms/opt/go/src/internal/coverage/encodecounter/encode.go:71 > > > +0x97 > > > runtime/coverage.(*emitState).emitCounterDataFile() > > > /home/ms/opt/go/src/runtime/coverage/emit.go:573 +0x91 > > > runtime/coverage.emitCounterDataToDirectory() > > > /home/ms/opt/go/src/runtime/coverage/emit.go:322 +0x310 > > > runtime/coverage.processCoverTestDir() > > > /home/ms/opt/go/src/runtime/coverage/testsupport.go:39 +0x1c4 > > > main.coverTearDown() > > > _testmain.go:179 +0x159 > > > testing.coverReport2() > > > /home/ms/opt/go/src/testing/newcover.go:37 +0xcb > > > testing.coverReport() > > > /home/ms/opt/go/src/testing/cover.go:83 +0xc74 > > > testing.(*M).writeProfiles() > > > /home/ms/opt/go/src/testing/testing.go:2053 +0xc6f > > > testing.(*M).after.func1() > > > /home/ms/opt/go/src/testing/testing.go:1987 +0x30 > > > sync.(*Once).doSlow() > > > /home/ms/opt/go/src/sync/once.go:74 +0x101 > > > sync.(*Once).Do() > > > /home/ms/opt/go/src/sync/once.go:65 +0x46 > > > testing.(*M).after() > > > /home/ms/opt/go/src/testing/testing.go:1986 +0x55 > > > testing.(*M).Run.func4() > > > /home/ms/opt/go/src/testing/testing.go:1761 +0x39 > > > runtime.deferreturn() > > > /home/ms/opt/go/src/runtime/panic.go:476 +0x32 > > > testing.(*M).Run() > > > /home/ms/opt/go/src/testing/testing.go:1771 +0xbb3 > > > github.com/shuLhan/share/lib/dns.TestMain() > > > /home/ms/go/src/github.com/shuLhan/share/lib/dns/dns_test.go:63 > > > +0x5db > > > main.main() > > > _testmain.go:192 +0x33d > > > > > > Previous write at 0x000001e5f04c by goroutine 9: > > > sync/atomic.AddInt32() > > > /home/ms/opt/go/src/runtime/race_amd64.s:281 +0xb > > > sync/atomic.AddUint32() > > > <autogenerated>:1 +0x1a > > > github.com/shuLhan/share/lib/dns.(*Server).processRequest() > > > /home/ms/go/src/github.com/shuLhan/share/lib/dns/server.go:593 > > > +0xc67 > > > github.com/shuLhan/share/lib/dns.(*Server).ListenAndServe.func1() > > > /home/ms/go/src/github.com/shuLhan/share/lib/dns/server.go:187 > > > +0x39 > > > > > > Goroutine 9 (running) created at: > > > github.com/shuLhan/share/lib/dns.(*Server).ListenAndServe() > > > /home/ms/go/src/github.com/shuLhan/share/lib/dns/server.go:187 > > > +0xe6 github.com/shuLhan/share/lib/dns.TestMain.func1() > > > /home/ms/go/src/github.com/shuLhan/share/lib/dns/dns_test.go:54 > > > +0x44 > > > ================== > > > ... > > > ---- > > > > > > There are many lines like that with the same pattern. > > > > > > In the above snippet, the lib/dns/dns_test.go:63 point this code > > > [1], > > > > > > os.Exit(m.Run()) > > > > > > So it does not make sense if the data race is in my code. > > > > > > A quick bisect point to this commit [2]. > > > > > Just want to be clear, I run the test using > GOEXPERIMENT=coverageredesign flag using Go tip commit 53773a5d08 > > $ go version > go version devel go1.20-53773a5d08 Wed Sep 28 11:50:58 2022 +0000 > linux/amd64 > > Without GOEXPERIMENT flag, > > $ CGO_ENABLED=1 go test -race -coverprofile=cover.out ./lib/dns > ok github.com/shuLhan/share/lib/dns 0.707s coverage: > 56.8% of statements > > With GOEXPERIMENT=coverageredesign flag, > > ---- > $ GOEXPERIMENT=coverageredesign CGO_ENABLED=1 go test -race ./lib/dns > ok github.com/shuLhan/share/lib/dns 0.683s > > $ GOEXPERIMENT=coverageredesign CGO_ENABLED=1 go test -race > -coverprofile=cover.out ./lib/dns > dns.Server: listening for DNS over TLS at 127.0.0.1:18053 > dns.Server: listening for DNS over TCP at 127.0.0.1:5300 > dns.Server: listening for DNS over UDP at 127.0.0.1:5300 > dns.Server: listening for DNS over HTTPS at 127.0.0.1:8443 > dns: invalid IP address "localhost" > dns: invalid name server URI "://127.0.0.1" > dns: invalid IP address "localhost:53" > dns: invalid IP address "localhost:53" > PASS > ================== > WARNING: DATA RACE > Read at 0x000001e5f04c by main goroutine: > > internal/coverage/encodecounter.(*CoverageDataWriter).writeCounters.func2() > /home/ms/opt/go/src/internal/coverage/encodecounter/encode.go:261 > +0x11c > runtime/coverage.(*emitState).VisitFuncs() > /home/ms/opt/go/src/runtime/coverage/emit.go:539 +0x6bc > internal/coverage/encodecounter.(*CoverageDataWriter).writeCounters() > /home/ms/opt/go/src/internal/coverage/encodecounter/encode.go:268 > +0x16f > ... > ---- > -- You received this message because you are 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