runtime.Caller return frame of bad function #39342

rekby · 2020-06-01T12:46:36Z

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

$ go version
go version go1.14.3 darwin/amd64

Does this issue reproduce with the latest release?

yes

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

darwin, amd64

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/rekby/Library/Caches/go-build"
GOENV="/Users/rekby/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GONOPROXY="*.yandex-team.ru,git.1gb.ru"
GONOSUMDB="*.yandex-team.ru,git.1gb.ru"
GOOS="darwin"
GOPATH="/Users/rekby/go"
GOPRIVATE="*.yandex-team.ru,git.1gb.ru"
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/Cellar/go/1.14.3/libexec"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.14.3/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/rekby/projects/rekby/tmp-go/go.mod"
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=/var/folders/8_/68c7r6rj6xg4fpjls__qtsjn18s1hz/T/go-build670439081=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

run go test

main_test.go

// main_test.go
package main
import (

"github.com/stretchr/testify/require"

"runtime"

"testing"

)
func TestCaller(t *testing.T) {

at := require.New(t)

var name string

func() {

name = getNameCaller(t)

}()

//t.Log(name)

at.True(hasSuffix(t, name, ".TestCaller"))

}
func TestCallers(t *testing.T) {

at := require.New(t)

var name string

func() {

name = getNameCallers(t)

}()

//t.Log(name)

at.True(hasSuffix(t, name, ".TestCallers"))

}
func hasSuffix(t *testing.T, s, suffix string) bool {

// copy from strings.hasSuffix, add t.Logf

a := len(s) >= len(suffix) && s[len(s)-len(suffix):] == suffix

t.Logf("%v: '%v' '%v'", a, s, suffix)

return a

}
func getNameCaller(t *testing.T) string {

caller, _, _, _ := runtime.Caller(2)

frames := runtime.CallersFrames([]uintptr{caller})

frame, _ := frames.Next()

return frame.Function

}
func getNameCallers(t *testing.T) string {

callers := make([]uintptr, 100)

callers = callers[:runtime.Callers(3, callers)]

frames := runtime.CallersFrames(callers)

frame, _ := frames.Next()

return frame.Function

}

go.mod

module tmp

go 1.14

require github.com/stretchr/testify v1.6.0

go.sum

github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.6.0 h1:jlIyCplCJFULU/01vCkhKuTyc3OorI3bJFuw6obfgho=
github.com/stretchr/testify v1.6.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

(error repeated if I clear go.mod, go.sum and re-init module)

What did you expect to see?

PASS

What did you see instead?

--- FAIL: TestCaller (0.00s)
    main_test.go:33: false: 'github.com/stretchr/testify/require.New' '.TestCaller'
    main_test.go:17:
        	Error Trace:	main_test.go:17
        	Error:      	Should be true
        	Test:       	TestCaller
FAIL
exit status 1
FAIL	tmp	0.102s

Test pass if I uncomment log in TestCaller (line 16//t.Log(name))
Test pass if I remove at := require.New(t) and use require.True(t, ...) instead.

The text was updated successfully, but these errors were encountered:

davecheney · 2020-06-01T13:13:26Z

This is related to inlining, try printing out the string who’s suffix does not match, that will give you a clue why the frame was off by one

rekby · 2020-06-01T14:56:30Z

@davecheney Yes, I understand about it is inline side effect.

Test out print strings:
I have pointer to 'github.com/stretchr/testify/require.New' func from Caller.

I surprised because runtime.Caller and runtime.Callers have different result for same situation.

Internal Caller(2) and Callers(3) run intenal callers(3), but have different result.

If the difference is expected - I think need write it in documentations and write in documentation about what of function have more precision.

randall77 · 2020-06-01T16:27:26Z

runtime.CallersFrames must take the result of runtime.Callers. The slice you are constructing from the result of runtime.Caller is not an allowed input.

You should use runtime.FuncForPC with the pc result from runtime.Caller.

More generally, runtime.Caller is an old API which does not take into account inlining correctly. You should use runtime.Callers + runtime.CallersFrames whenever possible.

I'm going to close, as this isn't a bug. If you have concrete suggestions for improving the documentation, please reopen and include those suggestions (or send a CL).

randall77 closed this as completed Jun 1, 2020

golang locked and limited conversation to collaborators Jun 1, 2021

gopherbot added the FrozenDueToAge label Jun 1, 2021

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runtime.Caller return frame of bad function #39342

runtime.Caller return frame of bad function #39342

rekby commented Jun 1, 2020

davecheney commented Jun 1, 2020

rekby commented Jun 1, 2020 •

edited

randall77 commented Jun 1, 2020

runtime.Caller return frame of bad function #39342

runtime.Caller return frame of bad function #39342

Comments

rekby commented Jun 1, 2020

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

Does this issue reproduce with the latest release?

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

What did you do?

What did you expect to see?

What did you see instead?

davecheney commented Jun 1, 2020

rekby commented Jun 1, 2020 • edited

randall77 commented Jun 1, 2020

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

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

rekby commented Jun 1, 2020 •

edited