Add TestCallerPanic and get other tests to pass.

Author: ChrisHines

stack.go

@@ -79,7 +79,7 @@ var ErrNoFunc = errors.New("no call stack information")
 //    %#v   equivalent to %#s:%d
 func (c Call) Format(s fmt.State, verb rune) {
 	frames := runtime.CallersFrames(c.pcs[:])
-	head , _ := frames.Next()
+	head, _ := frames.Next()
 	frame, _ := frames.Next()
 
 	if head.Function == "runtime.signpanic" {
@@ -158,17 +158,10 @@ func (c Call) PC() uintptr {
 	return c.pcs[1]
 }
 
-func (c Call) frame() (*runtime.Frame) {
+func (c Call) frame() *runtime.Frame {
 	frames := runtime.CallersFrames(c.pcs[:])
-
 	frame, _ := frames.Next()
-	next, _ := frames.Next()
-	if frame.Function == "runtime.sigpanic" {
-		frame, _ = runtime.CallersFrames([]uintptr{next.PC - 1}).Next()
-	} else {
-		frame = next
-	}
-
+	frame, _ = frames.Next()
 	return &frame
 }
 
@@ -269,8 +262,8 @@ func Trace() CallStack {
 	cs := make([]Call, n)
 
 	for i := range pcs[:n] {
-		cs[i] = Call {
-			pcs: [2]uintptr{pcs[i], pcs[i + 1]},
+		cs[i] = Call{
+			pcs: [2]uintptr{pcs[i], pcs[i+1]},
 		}
 	}
 

stackinternal_test.go

@@ -3,9 +3,6 @@ package stack
 import (
 	"runtime"
 	"testing"
-	"github.com/dkushner/stack"
-	"strings"
-	"strconv"
 )
 
 func TestCaller(t *testing.T) {
@@ -27,6 +24,49 @@ func TestCaller(t *testing.T) {
 	}
 }
 
+func TestCallerPanic(t *testing.T) {
+	t.Parallel()
+
+	var (
+		line int
+		ok   bool
+	)
+
+	defer func() {
+		if recover() != nil {
+			// count frames to runtime.sigpanic
+			panicIdx := -1
+			for i, c := range Trace() {
+				if c.name() == "runtime.sigpanic" {
+					panicIdx = i
+					break
+				}
+			}
+			if panicIdx == -1 {
+				t.Fatal("no runtime.sigpanic entry on the stack")
+			}
+			if got, want := Caller(panicIdx).name(), "runtime.sigpanic"; got != want {
+				t.Errorf("sigpanic frame: got name == %v, want name == %v", got, want)
+			}
+			if got, want := Caller(panicIdx+1).name(), "github.com/go-stack/stack.TestCallerPanic"; got != want {
+				t.Errorf("TestCallerPanic frame: got name == %v, want name == %v", got, want)
+			}
+			if got, want := Caller(panicIdx+1).line(), line; got != want {
+				t.Errorf("TestCallerPanic frame: got line == %v, want line == %v", got, want)
+			}
+		}
+	}()
+
+	_, _, line, ok = runtime.Caller(0)
+	line += 7 // adjust to match line of panic below
+	if !ok {
+		t.Fatal("runtime.Caller(0) failed")
+	}
+	// Initiate a sigpanic.
+	var x *uintptr
+	_ = *x
+}
+
 type fholder struct {
 	f func() CallStack
 }
@@ -35,12 +75,16 @@ func (fh *fholder) labyrinth() CallStack {
 	for {
 		return fh.f()
 	}
-	panic("this line only needed for go 1.0")
 }
 
 func TestTrace(t *testing.T) {
 	t.Parallel()
 
+	_, _, line, ok := runtime.Caller(0)
+	if !ok {
+		t.Fatal("runtime.Caller(0) failed")
+	}
+
 	fh := fholder{
 		f: func() CallStack {
 			cs := Trace()
@@ -50,7 +94,7 @@ func TestTrace(t *testing.T) {
 
 	cs := fh.labyrinth()
 
-	lines := []int{46, 36, 51}
+	lines := []int{line + 7, line - 7, line + 12}
 
 	for i, line := range lines {
 		if got, want := cs[i].line(), line; got != want {
@@ -63,39 +107,43 @@ func TestTrace(t *testing.T) {
 func TestTracePanic(t *testing.T) {
 	t.Parallel()
 
+	var (
+		line int
+		ok   bool
+	)
+
 	defer func() {
 		if recover() != nil {
-			trace := stack.Trace().TrimRuntime()
-
-			if len(trace) != 6 {
-				t.Errorf("got len(trace) == %v, want %v", len(trace), 6)
-			}
-
-			// Check frames in this file, the interceding frames are somewhat
-			// platform-dependent.
-			lines := []int64{68, 101}
-
-			var local []int64
-			for _, call := range trace {
-				parts := strings.Split(call.String(), ":")
-				if parts[0] == "stackinternal_test.go" {
-					line, _ := strconv.ParseInt(parts[1], 10, 32)
-					local = append(local, line)
+			trace := Trace()
+
+			// find runtime.sigpanic
+			panicIdx := -1
+			for i, c := range trace {
+				if c.name() == "runtime.sigpanic" {
+					panicIdx = i
+					break
 				}
 			}
-
-			if len(local) != 2 {
-				t.Errorf("expected %v local frames but got %v", 2, len(local))
+			if panicIdx == -1 {
+				t.Fatal("no runtime.sigpanic entry on the stack")
 			}
-
-			for i, line := range lines {
-				if got, want := local[i], line; got != want {
-					t.Errorf("got line[%d] == %v, want line[%d] == %v", i, got, i, want)
-				}
+			if got, want := trace[panicIdx].name(), "runtime.sigpanic"; got != want {
+				t.Errorf("sigpanic frame: got name == %v, want name == %v", got, want)
+			}
+			if got, want := trace[panicIdx+1].name(), "github.com/go-stack/stack.TestTracePanic"; got != want {
+				t.Errorf("TestTracePanic frame: got name == %v, want name == %v", got, want)
+			}
+			if got, want := trace[panicIdx+1].line(), line; got != want {
+				t.Errorf("TestTracePanic frame: got line == %v, want line == %v", got, want)
 			}
 		}
 	}()
 
+	_, _, line, ok = runtime.Caller(0)
+	line += 7 // adjust to match line of panic below
+	if !ok {
+		t.Fatal("runtime.Caller(0) failed")
+	}
 	// Initiate a sigpanic.
 	var x *uintptr
 	_ = *x