runtime/debug: do not require a GOROOT/src prefix in TestStack

When paths are trimmed, the reported file locations begin with the
package import path (not GOROOT/src).

Updates #51461.

Change-Id: Ia6814f970aee11f3d933e75c75136d679d19e220
Reviewed-on: https://go-review.googlesource.com/c/go/+/391815
Trust: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

diff --git a/src/runtime/debug/stack_test.go b/src/runtime/debug/stack_test.go
index 4cab8864df4cc33a5e3d6e2fd3e2c3efaa1e0dc8..671057c3a0d1b6de07fed3db5d26bfb63325a6cb 100644 (file)
--- a/src/runtime/debug/stack_test.go
+++ b/src/runtime/debug/stack_test.go
@@ -5,11 +5,26 @@
 package debug_test
 
 import (
+       "bytes"
+       "fmt"
+       "internal/testenv"
+       "os"
+       "os/exec"
+       "path/filepath"
+       "runtime"
        . "runtime/debug"
        "strings"
        "testing"
 )
 
+func TestMain(m *testing.M) {
+       if os.Getenv("GO_RUNTIME_DEBUG_TEST_DUMP_GOROOT") != "" {
+               fmt.Println(runtime.GOROOT())
+               os.Exit(0)
+       }
+       os.Exit(m.Run())
+}
+
 type T int
 
 func (t *T) ptrmethod() []byte {
@@ -43,23 +58,64 @@ func TestStack(t *testing.T) {
        if len(lines) < 6 {
                t.Fatal("too few lines")
        }
+
+       // If built with -trimpath, file locations should start with package paths.
+       // Otherwise, file locations should start with a GOROOT/src prefix
+       // (for whatever value of GOROOT is baked into the binary, not the one
+       // that may be set in the environment).
+       fileGoroot := ""
+       if envGoroot := os.Getenv("GOROOT"); envGoroot != "" {
+               // Since GOROOT is set explicitly in the environment, we can't be certain
+               // that it is the same GOROOT value baked into the binary, and we can't
+               // change the value in-process because runtime.GOROOT uses the value from
+               // initial (not current) environment. Spawn a subprocess to determine the
+               // real baked-in GOROOT.
+               t.Logf("found GOROOT %q from environment; checking embedded GOROOT value", envGoroot)
+               testenv.MustHaveExec(t)
+               exe, err := os.Executable()
+               if err != nil {
+                       t.Fatal(err)
+               }
+               cmd := exec.Command(exe)
+               cmd.Env = append(os.Environ(), "GOROOT=", "GO_RUNTIME_DEBUG_TEST_DUMP_GOROOT=1")
+               out, err := cmd.Output()
+               if err != nil {
+                       t.Fatal(err)
+               }
+               fileGoroot = string(bytes.TrimSpace(out))
+       } else {
+               // Since GOROOT is not set in the environment, its value (if any) must come
+               // from the path embedded in the binary.
+               fileGoroot = runtime.GOROOT()
+       }
+       filePrefix := ""
+       if fileGoroot != "" {
+               filePrefix = filepath.ToSlash(fileGoroot) + "/src/"
+       }
+
        n := 0
-       frame := func(line, code string) {
-               check(t, lines[n], code)
+       frame := func(file, code string) {
+               t.Helper()
+
+               line := lines[n]
+               if !strings.Contains(line, code) {
+                       t.Errorf("expected %q in %q", code, line)
+               }
                n++
-               check(t, lines[n], line)
+
+               line = lines[n]
+
+               wantPrefix := "\t" + filePrefix + file
+               if !strings.HasPrefix(line, wantPrefix) {
+                       t.Errorf("in line %q, expected prefix %q", line, wantPrefix)
+               }
                n++
        }
        n++
-       frame("src/runtime/debug/stack.go", "runtime/debug.Stack")
-       frame("src/runtime/debug/stack_test.go", "runtime/debug_test.(*T).ptrmethod")
-       frame("src/runtime/debug/stack_test.go", "runtime/debug_test.T.method")
-       frame("src/runtime/debug/stack_test.go", "runtime/debug_test.TestStack")
-       frame("src/testing/testing.go", "")
-}
 
-func check(t *testing.T, line, has string) {
-       if !strings.Contains(line, has) {
-               t.Errorf("expected %q in %q", has, line)
-       }
+       frame("runtime/debug/stack.go", "runtime/debug.Stack")
+       frame("runtime/debug/stack_test.go", "runtime/debug_test.(*T).ptrmethod")
+       frame("runtime/debug/stack_test.go", "runtime/debug_test.T.method")
+       frame("runtime/debug/stack_test.go", "runtime/debug_test.TestStack")
+       frame("testing/testing.go", "")
 }