From bc44c5f4c085607d28a1ab051a287c5c648c7ba7 Mon Sep 17 00:00:00 2001
From: david-littlefarmer <david.littlefarmer@gmail.com>
Date: Mon, 30 Oct 2023 15:54:20 +0100
Subject: [PATCH] max error stack trace frames as option

---
 devslog.go    |  5 ++++-
 stacktrace.go | 37 ++++++++++++++-----------------------
 2 files changed, 18 insertions(+), 24 deletions(-)

diff --git a/devslog.go b/devslog.go
index 67dc9cb..8cd47f4 100644
--- a/devslog.go
+++ b/devslog.go
@@ -52,6 +52,9 @@ type Options struct {
 
 	// Set color for Error level, default: devslog.Red
 	ErrorColor Color
+
+	// Max stack trace frames when unwrapping errors
+	MaxErrorStackTrace uint
 }
 
 type groupOrAttrs struct {
@@ -404,7 +407,7 @@ func (h *developHandler) formatError(err error, l int) (b []byte) {
 		}
 		b = append(b, cs([]byte(errMsg), fgRed)...)
 
-		for j, fileLine := range getFileLineFromPC(extractPCFromError(err)) {
+		for j, fileLine := range h.getFileLineFromPC(h.extractPCFromError(err)) {
 			b = append(b, '\n')
 			tb := strconv.Itoa(j)
 			b = append(b, bytes.Repeat([]byte(" "), l*2+6)...)
diff --git a/stacktrace.go b/stacktrace.go
index 618211e..303272a 100644
--- a/stacktrace.go
+++ b/stacktrace.go
@@ -6,9 +6,7 @@ import (
 	"runtime"
 )
 
-var MaxStackTraceFrames int = 2
-
-func getFileLineFromPC(pcs []uintptr) (fileLines []string) {
+func (h *developHandler) getFileLineFromPC(pcs []uintptr) (fileLines []string) {
 	if len(pcs) == 0 {
 		return nil
 	}
@@ -17,7 +15,6 @@ func getFileLineFromPC(pcs []uintptr) (fileLines []string) {
 	for {
 		fr, more := frames.Next()
 		fileLines = append(fileLines, fmt.Sprintf("%v:%v", fr.File, fr.Line))
-
 		if !more {
 			break
 		}
@@ -30,19 +27,18 @@ func getFileLineFromPC(pcs []uintptr) (fileLines []string) {
 // - github.com/pkg/errors
 // - golang.org/x/xerrors
 // - golang.org/x/exp/errors
-func extractPCFromError(err error) (pc []uintptr) {
-	if MaxStackTraceFrames == 0 {
+func (h *developHandler) extractPCFromError(err error) (pc []uintptr) {
+	if h.opts.MaxErrorStackTrace == 0 {
 		return nil
 	}
 
 	v := reflect.ValueOf(err)
-
-	pc = extractPCFromPkgErrors(v)
+	pc = h.extractPCFromPkgErrors(v)
 	if len(pc) > 0 {
 		return pc
 	}
 
-	pc = extractPCFromExpErrors(v)
+	pc = h.extractPCFromExpErrors(v)
 	if len(pc) > 0 {
 		return pc
 	}
@@ -50,7 +46,7 @@ func extractPCFromError(err error) (pc []uintptr) {
 	return pc
 }
 
-func extractPCFromPkgErrors(v reflect.Value) (pc []uintptr) {
+func (h *developHandler) extractPCFromPkgErrors(v reflect.Value) (pc []uintptr) {
 	// https://github.com/pkg/errors/blob/master/stack.go#L155
 	//
 	// type stackTracer interface {
@@ -63,24 +59,26 @@ func extractPCFromPkgErrors(v reflect.Value) (pc []uintptr) {
 	if !v.IsValid() {
 		return nil
 	}
+
 	v = v.Call(nil)[0]
 	if v.Kind() != reflect.Slice {
 		return nil
 	}
 
 	// Get up to two frames from github.com/pkg/errors StackTrace.
-	for i := 0; i < min(v.Len(), MaxStackTraceFrames); i++ {
+	for i := 0; i < min(v.Len(), int(h.opts.MaxErrorStackTrace)); i++ {
 		index := v.Index(i)
 		if !index.CanUint() {
 			return pc
 		}
+
 		pc = append(pc, uintptr(index.Uint()))
 	}
 
 	return pc
 }
 
-func extractPCFromExpErrors(v reflect.Value) (pc []uintptr) {
+func (h *developHandler) extractPCFromExpErrors(v reflect.Value) (pc []uintptr) {
 	// https://cs.opensource.google/go/x/exp/+/92128663:errors/fmt/errors.go;l=24
 	// https://cs.opensource.google/go/x/exp/+/92128663:errors/errors.go;l=25
 	//
@@ -103,9 +101,11 @@ func extractPCFromExpErrors(v reflect.Value) (pc []uintptr) {
 	if v.Kind() == reflect.Ptr && !v.IsNil() {
 		v = v.Elem()
 	}
+
 	if v.Kind() != reflect.Struct {
 		return nil
 	}
+
 	v = v.FieldByName("frame")
 	if v.Kind() != reflect.Struct {
 		return nil
@@ -123,23 +123,14 @@ func extractPCFromExpErrors(v reflect.Value) (pc []uintptr) {
 
 	// Skip first frame pointing at fmt.Errorf() or errors.New().
 	skip := 1
-
-	for i := skip; i < min(v.Len(), skip+MaxStackTraceFrames); i++ {
+	for i := skip; i < min(v.Len(), skip+int(h.opts.MaxErrorStackTrace)); i++ {
 		index := v.Index(i)
 		if !index.CanUint() {
 			return nil
 		}
+
 		pc = append(pc, uintptr(index.Uint()))
 	}
 
 	return pc
 }
-
-// As of Go 1.21, we could use the built-in min() function.
-// This function provides backward compatibility with older versions of Go.
-func min(i int, j int) int {
-	if i < j {
-		return i
-	}
-	return j
-}