From 71fa7d7d64785c98d3814e53b3544fd8cccff897 Mon Sep 17 00:00:00 2001
From: Chris Hines <github@cs-guy.com>
Date: Thu, 16 Sep 2021 22:55:19 -0400
Subject: [PATCH] Simplify stack helpers and remove internal/stack package
 (#11)

---
 internal/stack/stack.go | 38 --------------------------------------
 log_test.go             | 31 +++++++++++++++++++++++++++----
 2 files changed, 27 insertions(+), 42 deletions(-)
 delete mode 100644 internal/stack/stack.go

diff --git a/internal/stack/stack.go b/internal/stack/stack.go
deleted file mode 100644
index b0acb15..0000000
--- a/internal/stack/stack.go
+++ /dev/null
@@ -1,38 +0,0 @@
-package stack
-
-import "runtime"
-
-// Caller returns a frame from the stack of the current goroutine. The argument
-// skip is the number of frames to ascend, with 0 identifying the
-// calling function.
-func Caller(skip int) runtime.Frame {
-	var pcs [3]uintptr
-
-	n := runtime.Callers(skip+1, pcs[:])
-	frames := runtime.CallersFrames(pcs[:n])
-	frame, _ := frames.Next()
-	frame, _ = frames.Next()
-
-	return frame
-}
-
-// Trace returns a call stack for the current goroutine with element 0
-// identifying the calling function.
-func Trace() []runtime.Frame {
-	var pcs [512]uintptr
-	n := runtime.Callers(1, pcs[:])
-
-	frames := runtime.CallersFrames(pcs[:n])
-	cs := make([]runtime.Frame, 0, n)
-
-	// Skip extra frame retrieved just to make sure the runtime.sigpanic
-	// special case is handled.
-	frame, more := frames.Next()
-
-	for more {
-		frame, more = frames.Next()
-		cs = append(cs, frame)
-	}
-
-	return cs
-}
diff --git a/log_test.go b/log_test.go
index 76a4582..8a0e15c 100644
--- a/log_test.go
+++ b/log_test.go
@@ -2,11 +2,11 @@ package log_test
 
 import (
 	"bytes"
+	"runtime"
 	"sync"
 	"testing"
 
 	"github.com/go-kit/log"
-	"github.com/go-kit/log/internal/stack"
 )
 
 func TestContext(t *testing.T) {
@@ -108,7 +108,7 @@ func TestWithPrefixAndSuffix(t *testing.T) {
 // Valuers, regardless of how many times With has been called.
 func TestContextStackDepth(t *testing.T) {
 	t.Parallel()
-	fn := stack.Caller(0).Function
+	fn := callingFunctions()[0]
 
 	var output []interface{}
 
@@ -118,8 +118,8 @@ func TestContextStackDepth(t *testing.T) {
 	}))
 
 	stackValuer := log.Valuer(func() interface{} {
-		for i, f := range stack.Trace() {
-			if f.Function == fn {
+		for i, f := range callingFunctions() {
+			if f == fn {
 				return i
 			}
 		}
@@ -149,6 +149,29 @@ func TestContextStackDepth(t *testing.T) {
 	}
 }
 
+// callingFunctions returns the names of the functions on the call stack for the
+// current goroutine with element 0 identifying the calling function.
+func callingFunctions() []string {
+	pcs := make([]uintptr, 10)
+	n := runtime.Callers(2, pcs)
+	if n == 0 {
+		return nil
+	}
+
+	frames := runtime.CallersFrames(pcs[:n])
+	funcs := make([]string, 0, n)
+
+	for {
+		frame, more := frames.Next()
+		funcs = append(funcs, frame.Function)
+		if !more {
+			break
+		}
+	}
+
+	return funcs
+}
+
 // Test that With returns a Logger safe for concurrent use. This test
 // validates that the stored logging context does not get corrupted when
 // multiple clients concurrently log additional keyvals.