Change takeStacktrace skip parameter to a value

field.go

@@ -368,7 +368,7 @@ func Stack(key string) Field {
 	// from expanding the zapcore.Field union struct to include a byte slice. Since
 	// taking a stacktrace is already so expensive (~10us), the extra allocation
 	// is okay.
-	return String(key, takeStacktrace(nil))
+	return String(key, takeStacktrace(0))
 }
 
 // StackSkip constructs a field that stores a stacktrace of the current
@@ -381,7 +381,7 @@ func StackSkip(key string, skip int) Field {
 	// from expanding the zapcore.Field union struct to include a byte slice. Since
 	// taking a stacktrace is already so expensive (~10us), the extra allocation
 	// is okay.
-	return String(key, takeStacktrace(&skip))
+	return String(key, takeStacktrace(skip))
 }
 
 // Duration constructs a field with the given key and value. The encoder

field_test.go

@@ -259,6 +259,6 @@ func TestStackField(t *testing.T) {
 	f := Stack("stacktrace")
 	assert.Equal(t, "stacktrace", f.Key, "Unexpected field key.")
 	assert.Equal(t, zapcore.StringType, f.Type, "Unexpected field type.")
-	assert.Equal(t, takeStacktrace(nil), f.String, "Unexpected stack trace")
+	assert.Equal(t, takeStacktrace(0), f.String, "Unexpected stack trace")
 	assertCanBeReused(t, f)
 }

stacktrace.go

@@ -43,7 +43,7 @@ var (
 	_zapStacktraceVendorContains = addPrefix("/vendor/", _zapStacktracePrefixes...)
 )
 
-func takeStacktrace(skip *int) string {
+func takeStacktrace(skip int) string {
 	buffer := bufferpool.Get()
 	defer buffer.Free()
 	programCounters := _stacktracePool.Get().(*programCounters)
@@ -69,19 +69,15 @@ func takeStacktrace(skip *int) string {
 	// Note: On the last iteration, frames.Next() returns false, with a valid
 	// frame, but we ignore this frame. The last frame is a a runtime frame which
 	// adds noise, since it's only either runtime.main or runtime.goexit.
-	toSkip := 0
-	if skip != nil {
-		toSkip = *skip
-	}
 	for frame, more := frames.Next(); more; frame, more = frames.Next() {
 		if skipZapFrames && isZapFrame(frame.Function) {
 			continue
 		} else {
 			skipZapFrames = false
 		}
 
-		if toSkip > 0 {
-			toSkip--
+		if skip > 0 {
+			skip--
 			continue
 		}
 

stacktrace_test.go

@@ -29,7 +29,7 @@ import (
 )
 
 func TestTakeStacktrace(t *testing.T) {
-	trace := takeStacktrace(nil)
+	trace := takeStacktrace(0)
 	lines := strings.Split(trace, "\n")
 	require.True(t, len(lines) > 0, "Expected stacktrace to have at least one frame.")
 	assert.Contains(
@@ -70,6 +70,6 @@ func TestIsZapFrame(t *testing.T) {
 
 func BenchmarkTakeStacktrace(b *testing.B) {
 	for i := 0; i < b.N; i++ {
-		takeStacktrace(nil)
+		takeStacktrace(0)
 	}
 }