Improve support for older versions of Go.

Author: ChrisHines

format_test.go

@@ -1,3 +1,5 @@
+// +build go1.2
+
 package stack_test
 
 import (
@@ -7,13 +9,13 @@ import (
 )
 
 func Example_callFormat() {
-	log("%+s")
-	log("%v   %[1]n()")
+	logCaller("%+s")
+	logCaller("%v   %[1]n()")
 	// Output:
 	// github.com/go-stack/stack/format_test.go
-	// format_test.go:11   Example_callFormat()
+	// format_test.go:13   Example_callFormat()
 }
 
-func log(format string) {
+func logCaller(format string) {
 	fmt.Printf(format+"\n", stack.Caller(1))
 }

stack.go

@@ -262,18 +262,22 @@ func init() {
 	}
 }
 
-func inGoroot(path string) bool {
+func inGoroot(c Call) bool {
+	file := c.file()
+	if len(file) == 0 || file[0] == '?' {
+		return true
+	}
 	if runtime.GOOS == "windows" {
-		path = strings.ToLower(path)
+		file = strings.ToLower(file)
 	}
-	return strings.HasPrefix(path, goroot)
+	return strings.HasPrefix(file, goroot)
 }
 
 // TrimRuntime returns a slice of the CallStack with the topmost entries from
-// the go runtime removed. It considers any calls originating from files under
-// GOROOT as part of the runtime.
+// the go runtime removed. It considers any calls originating from unknown
+// files or files under GOROOT as part of the runtime.
 func (cs CallStack) TrimRuntime() CallStack {
-	for len(cs) > 0 && inGoroot(cs[len(cs)-1].file()) {
+	for len(cs) > 0 && inGoroot(cs[len(cs)-1]) {
 		cs = cs[:len(cs)-1]
 	}
 	return cs

stack12.go

@@ -7,12 +7,14 @@ import (
 )
 
 func getUintptrs() []uintptr {
+	var s []uintptr
 	select {
-	case s := <-pcStackPool:
-		return s[:cap(s)]
+	case s = <-pcStackPool:
+		s = s[:cap(s)]
 	default:
-		return make([]uintptr, 1000)
+		s = make([]uintptr, 1000)
 	}
+	return s
 }
 
 func putUintptrs(s []uintptr) {

stack_test.go

@@ -56,7 +56,6 @@ func TestCallFormat(t *testing.T) {
 		{c, "func", "%v", fmt.Sprint(path.Base(file), ":", line)},
 		{c, "func", "%+v", fmt.Sprint(relFile, ":", line)},
 		{c, "func", "%#v", fmt.Sprint(file, ":", line)},
-		{c, "func", "%v|%[1]n()", fmt.Sprint(path.Base(file), ":", line, "|", "TestCallFormat()")},
 
 		{c2, "meth", "%s", path.Base(file2)},
 		{c2, "meth", "%+s", relFile2},
@@ -67,7 +66,6 @@ func TestCallFormat(t *testing.T) {
 		{c2, "meth", "%v", fmt.Sprint(path.Base(file2), ":", line2)},
 		{c2, "meth", "%+v", fmt.Sprint(relFile2, ":", line2)},
 		{c2, "meth", "%#v", fmt.Sprint(file2, ":", line2)},
-		{c2, "meth", "%v|%[1]n()", fmt.Sprint(path.Base(file2), ":", line2, "|", "testType.testMethod()")},
 	}
 
 	for _, d := range data {
@@ -213,7 +211,7 @@ func BenchmarkFuncForPC(b *testing.B) {
 		fn = runtime.FuncForPC(pc)
 	}
 	b.StopTimer()
-	b.Log(fn.FileLine(pc))
+	fmt.Fprint(ioutil.Discard, fn.Entry())
 }
 
 func deepStack(depth int, b *testing.B) stack.CallStack {