cmd/go: add test to ensure the correct line number is displayed when using TB.Helper with race detector

[maxatome]

Similar problem referenced in #21631

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

go version go1.10.3 freebsd/amd64

go version go1.11rc1 freebsd/amd64

Does this issue reproduce with the latest release?

yes, but a little differently

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

GOARCH="amd64"
GOBIN=""
GOCACHE="/home/max/.cache/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="freebsd"
GOOS="freebsd"
GOPATH="/home/max/Projet/go"
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/freebsd_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build991380835=/tmp/go-build -gno-record-gcc-switches"

What did you do?

testing_test.go:

package testing_test

import "testing"

type TestingT interface {
	Helper()
	Log(args ...interface{})
}

func directCall(t *testing.T) {
	t.Helper()
	t.Log("directCall")
}

func interfaceTBCall(t testing.TB) {
	t.Helper()
	t.Log("interfaceTBCall")
}

func interfaceCall(t TestingT) {
	t.Helper()
	t.Log("interfaceCall")
}

func TestTesting(t *testing.T) {
	directCall(t)
	interfaceTBCall(t)
	interfaceCall(t)
}

Then

go test -v -race

What did you expect to see?

=== RUN   TestTesting
--- PASS: TestTesting (0.00s)
	testing_test.go:26: directCall
	testing_test.go:27: interfaceTBCall
	testing_test.go:28: interfaceCall
PASS
ok  	_/home/max	1.035s

(in fact the same output as without the -race flag.)

What did you see instead?

With go1.10.3:

=== RUN   TestTesting
--- PASS: TestTesting (0.00s)
	testing_test.go:26: directCall
	testing_test.go:17: interfaceTBCall
	testing_test.go:22: interfaceCall
PASS
ok  	_/home/max	1.035s

With go1.11rc1:

=== RUN   TestTesting
--- PASS: TestTesting (0.00s)
    testing_test.go:26: directCall
    <autogenerated>:1: interfaceTBCall
    <autogenerated>:1: interfaceCall
PASS
ok  	_/home/max	1.074s

[andybons]

@rsc @bcmills @ianlancetaylor @dvyukov

[maxatome]

@andybons just tested with go1.12beta1 and still the same:

> go version   
go version devel +e3b4b7baad Tue Dec 18 23:01:06 2018 +0000 freebsd/amd64
> go test -v -race   
=== RUN   TestTesting
--- PASS: TestTesting (0.00s)
    testing_test.go:26: directCall
    <autogenerated>:1: interfaceTBCall
    <autogenerated>:1: interfaceCall
PASS
ok  	_/home/max/t	1.016s

[maxatome]

@andybons go1.12beta2 seems to correct the problem:

> go version      
go version devel +4b3f04c63b Thu Jan 10 18:15:48 2019 +0000 freebsd/amd64
> go test -v -race
=== RUN   TestTesting
--- PASS: TestTesting (0.00s)
    testing_test.go:26: directCall
    testing_test.go:27: interfaceTBCall
    testing_test.go:28: interfaceCall
PASS
ok  	_/home/max/t 1.014s

As this bug is not mentioned in commits, I think its correction is a side effect of a recent change. Perhaps could one add a unit test to be sure it won't break again in the future?

[randall77]

This was probably fixed as part of the series of traceback fixes I've been making (as part of mid-stack inlining). A test would be great.

[gopherbot]

Change https://go.dev/cl/540016 mentions this issue: cmd/go: ensure the correct line number is displayed when using TB.Helper