From bff876d40bcdd92fa2beea917e66c7c25a5af1d1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emir=20Ribi=C4=87?= <e@ribic.ba>
Date: Tue, 3 Sep 2024 12:19:00 +0200
Subject: [PATCH] Function grouping prefix fix (#877)

---
 CHANGELOG.md                    |  1 +
 stacktrace.go                   |  7 ++-
 stacktrace_below_go1.21.go      |  7 +++
 stacktrace_below_go1.21_test.go | 17 +++++++
 stacktrace_go1.21.go            | 25 ++++++++++
 stacktrace_go1.21_test.go       | 81 +++++++++++++++++++++++++++++++++
 6 files changed, 137 insertions(+), 1 deletion(-)
 create mode 100644 stacktrace_below_go1.21.go
 create mode 100644 stacktrace_below_go1.21_test.go
 create mode 100644 stacktrace_go1.21.go
 create mode 100644 stacktrace_go1.21_test.go

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bfcd9ae0..096a84bb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 - Add trace origin to span data ([#849](https://github.com/getsentry/sentry-go/pull/849))
 - Add ability to skip frames in stacktrace ([#852](https://github.com/getsentry/sentry-go/pull/852))
 - Remove Martini integration ([#861](https://github.com/getsentry/sentry-go/pull/861))
+- Fix closure functions name grouping ([#877](https://github.com/getsentry/sentry-go/pull/877))
 
 ## 0.28.1
 
diff --git a/stacktrace.go b/stacktrace.go
index 67ea8007..06218ecf 100644
--- a/stacktrace.go
+++ b/stacktrace.go
@@ -311,7 +311,12 @@ func createFrames(frames []runtime.Frame, skip int) []Frame {
 		return []Frame{}
 	}
 
-	return result[:len(result)-skip]
+	result = result[:len(result)-skip]
+
+	// Fix issues grouping errors with the new fully qualified function names
+	// introduced from Go 1.21
+	result = cleanupFunctionNamePrefix(result)
+	return result
 }
 
 // TODO ID: why do we want to do this?
diff --git a/stacktrace_below_go1.21.go b/stacktrace_below_go1.21.go
new file mode 100644
index 00000000..35a42e4d
--- /dev/null
+++ b/stacktrace_below_go1.21.go
@@ -0,0 +1,7 @@
+//go:build !go1.21
+
+package sentry
+
+func cleanupFunctionNamePrefix(f []Frame) []Frame {
+	return f
+}
diff --git a/stacktrace_below_go1.21_test.go b/stacktrace_below_go1.21_test.go
new file mode 100644
index 00000000..35d50d31
--- /dev/null
+++ b/stacktrace_below_go1.21_test.go
@@ -0,0 +1,17 @@
+//go:build !go1.21
+
+package sentry
+
+import (
+	"testing"
+)
+
+func Test_cleanupFunctionNamePrefix(t *testing.T) {
+	f := []Frame{
+		{Function: "main.main"},
+		{Function: "main.main.func1"},
+	}
+	got := cleanupFunctionNamePrefix(f)
+	assertEqual(t, got, f)
+
+}
diff --git a/stacktrace_go1.21.go b/stacktrace_go1.21.go
new file mode 100644
index 00000000..45147c85
--- /dev/null
+++ b/stacktrace_go1.21.go
@@ -0,0 +1,25 @@
+//go:build go1.21
+
+package sentry
+
+import "strings"
+
+// Walk backwards through the results and for the current function name
+// remove it's parent function's prefix, leaving only it's actual name. This
+// fixes issues grouping errors with the new fully qualified function names
+// introduced from Go 1.21.
+
+func cleanupFunctionNamePrefix(f []Frame) []Frame {
+	for i := len(f) - 1; i > 0; i-- {
+		name := f[i].Function
+		parentName := f[i-1].Function + "."
+
+		if !strings.HasPrefix(name, parentName) {
+			continue
+		}
+
+		f[i].Function = name[len(parentName):]
+	}
+
+	return f
+}
diff --git a/stacktrace_go1.21_test.go b/stacktrace_go1.21_test.go
new file mode 100644
index 00000000..67c15990
--- /dev/null
+++ b/stacktrace_go1.21_test.go
@@ -0,0 +1,81 @@
+//go:build go1.21
+
+package sentry
+
+import (
+	"testing"
+)
+
+func Test_cleanupFunctionNamePrefix(t *testing.T) {
+	cases := map[string]struct {
+		f    []Frame
+		want []Frame
+	}{
+		"SimpleCase": {
+			f: []Frame{
+				{Function: "main.main"},
+				{Function: "main.main.func1"},
+			},
+			want: []Frame{
+				{Function: "main.main"},
+				{Function: "func1"},
+			},
+		},
+		"MultipleLevels": {
+			f: []Frame{
+				{Function: "main.main"},
+				{Function: "main.main.func1"},
+				{Function: "main.main.func1.func2"},
+			},
+			want: []Frame{
+				{Function: "main.main"},
+				{Function: "func1"},
+				{Function: "func2"},
+			},
+		},
+		"PrefixWithRun": {
+			f: []Frame{
+				{Function: "Run.main"},
+				{Function: "Run.main.func1"},
+			},
+			want: []Frame{
+				{Function: "Run.main"},
+				{Function: "func1"},
+			},
+		},
+		"NoPrefixMatch": {
+			f: []Frame{
+				{Function: "main.main"},
+				{Function: "main.handler"},
+			},
+			want: []Frame{
+				{Function: "main.main"},
+				{Function: "main.handler"},
+			},
+		},
+		"SingleFrame": {
+			f: []Frame{
+				{Function: "main.main"},
+			},
+			want: []Frame{
+				{Function: "main.main"},
+			},
+		},
+		"ComplexPrefix": {
+			f: []Frame{
+				{Function: "app.package.Run"},
+				{Function: "app.package.Run.Logger.func1"},
+			},
+			want: []Frame{
+				{Function: "app.package.Run"},
+				{Function: "Logger.func1"},
+			},
+		},
+	}
+	for name, tt := range cases {
+		t.Run(name, func(t *testing.T) {
+			got := cleanupFunctionNamePrefix(tt.f)
+			assertEqual(t, got, tt.want)
+		})
+	}
+}