fix(slog): take care of the generic case: the shape name in generic f…

…unction is replaced with "...".

go/log/slog/record.go

@@ -33,19 +33,9 @@ func source(r slog.Record) *slog.Source {
 func ShortSource(r slog.Record) *slog.Source {
 	fs := runtime.CallersFrames([]uintptr{r.PC})
 	f, _ := fs.Next()
-
-	function := path.Base(f.Function)
-	slash := strings.LastIndex(function, ".")
-	if slash >= 0 && slash+1 < len(function) {
-		function = function[slash+1:]
-	}
-	file := path.Base(f.File)
-	if file == "" {
-		file = "???"
-	}
 	return &slog.Source{
-		Function: function,
-		File:     path.Base(f.File),
+		Function: shortFunction(f.Function),
+		File:     shortFile(f.File),
 		Line:     f.Line,
 	}
 }
@@ -54,11 +44,34 @@ func ShortSource(r slog.Record) *slog.Source {
 // file keys in the data when ReportCaller is activated.
 // INFO[0000] main.go:23 main() hello world
 var ShortCallerPrettyfier = func(f *runtime.Frame) (function string, file string) {
-	funcname := path.Base(f.Function)
-	filename := path.Base(f.File)
+	funcname := shortFunction(f.Function)
+	filename := shortFile(f.File)
 	return fmt.Sprintf("%s()", funcname), fmt.Sprintf("%s:%d", filename, f.Line)
 }
 
+func shortFunction(function string) string {
+	function = path.Base(function)
+	prefix := function
+	// the shape name in generic function is replaced with "..."
+	// See: https://github.com/golang/go/blob/go1.22.5/src/runtime/traceback.go#L755
+	if i := strings.Index(function, "[...]"); i >= 0 {
+		prefix = function[:i]
+	}
+	slash := strings.LastIndex(prefix, ".")
+	if slash < 0 {
+		return function
+	}
+	return function[slash+1:]
+}
+
+func shortFile(file string) string {
+	_, name := path.Split(file)
+	if name == "" {
+		name = "???"
+	}
+	return name
+}
+
 // attrs returns the non-zero fields of s as a slice of attrs.
 // It is similar to a LogValue method, but we don't want Source
 // to implement LogValuer because it would be resolved before

go/log/slog/record_test.go

@@ -0,0 +1,75 @@
+// Copyright 2024 The searKing Author. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package slog
+
+import (
+	"testing"
+)
+
+func TestShortFunction(t *testing.T) {
+	for i, tt := range []struct {
+		function string
+		want     string
+	}{
+		{
+			"a",
+			"a",
+		},
+		{
+			"a.b",
+			"b",
+		},
+		{
+			"a.b.",
+			"",
+		},
+		{
+			"a.b.c[...]",
+			"c[...]",
+		},
+		{
+			"a.b.c[...].[...]....",
+			"c[...].[...]....",
+		},
+	} {
+
+		if got := shortFunction(tt.function); got != tt.want {
+			t.Errorf("#%d: got %s\nwant %s", i, got, tt.want)
+		}
+	}
+}
+
+func TestShortFile(t *testing.T) {
+	for i, tt := range []struct {
+		file string
+		want string
+	}{
+		{
+			"a.go",
+			"a.go",
+		},
+		{
+			"a/b/c.go",
+			"c.go",
+		},
+		{
+			"",
+			"???",
+		},
+		{
+			"/",
+			"???",
+		},
+		{
+			"a/b/",
+			"???",
+		},
+	} {
+
+		if got := shortFile(tt.file); got != tt.want {
+			t.Errorf("#%d: got %s\nwant %s", i, got, tt.want)
+		}
+	}
+}