fix(stacktrace): Correctly report package names

Makes function receivers part of the function name and not part of the
package name.

Consequently, filteredFrames needs only to compare the frame.Module
value (however confusing it is, since it holds a package name).

stacktrace.go

@@ -149,7 +149,7 @@ func NewFrame(f runtime.Frame) Frame {
 	abspath := f.File
 	filename := f.File
 	function := f.Function
-	var module string
+	var pkg string
 
 	if filename != "" {
 		filename = filepath.Base(filename)
@@ -162,14 +162,14 @@ func NewFrame(f runtime.Frame) Frame {
 	}
 
 	if function != "" {
-		module, function = deconstructFunctionName(function)
+		pkg, function = splitQualifiedFunctionName(function)
 	}
 
 	frame := Frame{
 		AbsPath:  abspath,
 		Filename: filename,
 		Lineno:   f.Line,
-		Module:   module,
+		Module:   pkg,
 		Function: function,
 	}
 
@@ -178,6 +178,15 @@ func NewFrame(f runtime.Frame) Frame {
 	return frame
 }
 
+// splitQualifiedFunctionName splits a package path-qualified function name into
+// package name and function name. Such qualified names are found in
+// runtime.Frame.Function values.
+func splitQualifiedFunctionName(name string) (pkg string, fun string) {
+	pkg = packageName(name)
+	fun = strings.TrimPrefix(name, pkg+".")
+	return
+}
+
 func extractFrames(pcs []uintptr) []Frame {
 	var frames []Frame
 	callersFrames := runtime.CallersFrames(pcs)
@@ -206,8 +215,7 @@ func filterFrames(frames []Frame) []Frame {
 			continue
 		}
 		// sentry internal frames
-		if frame.Module == "github.com/getsentry/sentry-go" ||
-			strings.HasPrefix(frame.Module, "github.com/getsentry/sentry-go.") {
+		if frame.Module == "github.com/getsentry/sentry-go" {
 			continue
 		}
 		filteredFrames = append(filteredFrames, frame)
@@ -226,21 +234,42 @@ func isInAppFrame(frame Frame) bool {
 	return true
 }
 
-// Transform `runtime/debug.*T·ptrmethod` into `{ module: runtime/debug, function: *T.ptrmethod }`
-func deconstructFunctionName(name string) (module string, function string) {
-	if idx := strings.LastIndex(name, "."); idx != -1 {
-		module = name[:idx]
-		function = name[idx+1:]
-	}
-	function = strings.Replace(function, "·", ".", -1)
-	return module, function
-}
-
 func callerFunctionName() string {
 	pcs := make([]uintptr, 1)
 	runtime.Callers(3, pcs)
 	callersFrames := runtime.CallersFrames(pcs)
 	callerFrame, _ := callersFrames.Next()
-	_, function := deconstructFunctionName(callerFrame.Function)
-	return function
+	return baseName(callerFrame.Function)
+}
+
+// packageName returns the package part of the symbol name, or the empty string
+// if there is none.
+// It replicates https://golang.org/pkg/debug/gosym/#Sym.PackageName, avoiding a
+// dependency on debug/gosym.
+func packageName(name string) string {
+	// A prefix of "type." and "go." is a compiler-generated symbol that doesn't belong to any package.
+	// See variable reservedimports in cmd/compile/internal/gc/subr.go
+	if strings.HasPrefix(name, "go.") || strings.HasPrefix(name, "type.") {
+		return ""
+	}
+
+	pathend := strings.LastIndex(name, "/")
+	if pathend < 0 {
+		pathend = 0
+	}
+
+	if i := strings.Index(name[pathend:], "."); i != -1 {
+		return name[:pathend+i]
+	}
+	return ""
+}
+
+// baseName returns the symbol name without the package or receiver name.
+// It replicates https://golang.org/pkg/debug/gosym/#Sym.BaseName, avoiding a
+// dependency on debug/gosym.
+func baseName(name string) string {
+	if i := strings.LastIndex(name, "."); i != -1 {
+		return name[i+1:]
+	}
+	return name
 }

stacktrace_test.go

@@ -1,8 +1,9 @@
 package sentry
 
 import (
-	"runtime"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
 func NewStacktraceForTest() *Stacktrace {
@@ -15,28 +16,52 @@ func (StacktraceTestHelper) NewStacktrace() *Stacktrace {
 	return NewStacktrace()
 }
 
-func TestFunctionName(t *testing.T) {
-	for _, test := range []struct {
-		skip int
-		pack string
-		name string
-	}{
-		{0, "sentry-go", "TestFunctionName"},
-		{1, "testing", "tRunner"},
-		{2, "runtime", "goexit"},
-		{100, "", ""},
-	} {
-		pc, _, _, _ := runtime.Caller(test.skip)
-		pack, name := deconstructFunctionName(runtime.FuncForPC(pc).Name())
-
-		// Go1.10 reports different paths than Modules aware versions (>=1.11)
-		assertStringContains(t, pack, test.pack)
-		assertEqual(t, name, test.name)
-	}
-}
-
 func BenchmarkNewStacktrace(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		Trace()
 	}
 }
+
+//nolint: scopelint // false positive https://github.com/kyoh86/scopelint/issues/4
+func TestSplitQualifiedFunctionName(t *testing.T) {
+	tests := []struct {
+		in  string
+		pkg string
+		fun string
+	}{
+		{"", "", ""},
+		{"runtime.Callers", "runtime", "Callers"},
+		{"main.main.func1", "main", "main.func1"},
+		{
+			"github.com/getsentry/sentry-go.Init",
+			"github.com/getsentry/sentry-go",
+			"Init",
+		},
+		{
+			"github.com/getsentry/sentry-go.(*Hub).Flush",
+			"github.com/getsentry/sentry-go",
+			"(*Hub).Flush",
+		},
+		{
+			"github.com/getsentry/sentry-go.Test.func2.1.1",
+			"github.com/getsentry/sentry-go",
+			"Test.func2.1.1",
+		},
+		{
+			"github.com/getsentry/confusing%2epkg%2ewith%2edots.Test.func1",
+			"github.com/getsentry/confusing%2epkg%2ewith%2edots",
+			"Test.func1",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.in, func(t *testing.T) {
+			pkg, fun := splitQualifiedFunctionName(tt.in)
+			if diff := cmp.Diff(tt.pkg, pkg); diff != "" {
+				t.Errorf("Package name mismatch (-want +got):\n%s", diff)
+			}
+			if diff := cmp.Diff(tt.fun, fun); diff != "" {
+				t.Errorf("Function name mismatch (-want +got):\n%s", diff)
+			}
+		})
+	}
+}