Handle failure of runtime.Caller

assert.go

@@ -27,20 +27,28 @@ func SetConfig(config Config) {
 //
 // WARN: This assertion is live!
 func Assert(condition bool, msg string, values ...any) {
-	assert(condition, msg, values...)
+	// We tell assert() to skip 2 frames here:
+	//  1. The assert() function itself
+	//  2. This Assert() function that calls assert()
+	assert(condition, msg, 2, values...) //nolint:mnd // Explained in comment
 }
 
 // Assert panics if the condition is false. Configurable via SetConfig.
-func assert(condition bool, msg string, values ...any) {
+// skipFrames is the number of stack frames to skip when getting the source context. 
+func assert(condition bool, msg string, skipFrames int, values ...any) {
 	if condition {
 		return // Assertion met
 	}
 
-	// Skip 2 frames:
-	// 1. this assert() function
-	// 2. the Assert() function that called us
-	_, file, line, _ := runtime.Caller(2) //nolint:mnd // Explained in comment
 
+	_, file, line, ok := runtime.Caller(skipFrames)
+
+	// Could not get Caller info
+	if !ok {
+		panic(AssertionError{
+			Message: msg,
+		})
+	}
 	// If values were provided for dumping
 	numValues := len(values)
 	if numValues%2 != 0 {

assert_debug.go

@@ -10,5 +10,8 @@ package assert
 //
 // WARN: Under the current build configuration, this assertion is enabled.
 func Debug(condition bool, msg string, values ...any) {
-	assert(condition, msg, values...)
+	// We tell assert() to skip 2 frames here:
+	//  1. The assert() function itself
+	//  2. This Debug() function that calls assert()
+	assert(condition, msg, 2, values...) //nolint:mnd // Explained in comment
 }

assert_test.go

@@ -289,3 +289,38 @@ func TestAssert_EmptyValues(t *testing.T) {
 		"empty_map", map[string]int{},
 	)
 }
+
+func TestAssertCallerFailure(t *testing.T) {
+	assertMessage := "This should fail to get caller info"
+	// Capture and verify the panic
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.Fatal("Expected panic, but none occurred")
+		}
+
+		ae, ok := r.(AssertionError)
+		if !ok {
+			t.Fatalf("Expected AssertionError, got %T", r)
+		}
+
+		// Verify we got the simplified error without file/line info
+		if ae.File != "" {
+			t.Errorf("Expected empty file, got %q", ae.File)
+		}
+		if ae.Line != 0 {
+			t.Errorf("Expected line to be 0, got %d", ae.Line)
+		}
+		if ae.SourceContext != "" {
+			t.Errorf("Expected empty source context, got %q", ae.SourceContext)
+		}
+		// Message should still be included
+		if ae.Message != assertMessage {
+			t.Errorf("Expected %q as error message, got %q", assertMessage, ae.Message)
+		}
+	}()
+
+	// Using the assert function (only accessible internally) instead of Assert
+	// to pass a specific skipFrames value 
+	assert(false, assertMessage, 1000)
+}

types.go

@@ -30,7 +30,11 @@ type AssertionError struct {
 func (e AssertionError) Error() string {
 	var sb strings.Builder
 
-	sb.WriteString(fmt.Sprintf("Assertion failed at %s:%d\n", e.File, e.Line))
+	if e.File != "" {
+		sb.WriteString(fmt.Sprintf("Assertion failed at %s:%d\n", e.File, e.Line))
+	} else {
+		sb.WriteString("Assertion failed (Runtime caller info is not available)\n")
+	}
 	sb.WriteString(fmt.Sprintf("Message: %s\n", e.Message))
 
 	if e.SourceContext != "" {