fix: max recursion depth exceeded

_appmap/event.py

@@ -455,7 +455,11 @@ class FuncReturnEvent(ReturnEvent):
 
     def __init__(self, parent_id, elapsed, return_value):
         super().__init__(parent_id, elapsed)
-        self.return_value = describe_value(None, return_value)
+        # Import here to prevent circular dependency
+        # pylint: disable=import-outside-toplevel
+        from _appmap.instrument import recording_disabled # noqa: F401
+        with recording_disabled():
+            self.return_value = describe_value(None, return_value)
 
 
 class HttpResponseEvent(ReturnEvent):

_appmap/instrument.py

@@ -15,11 +15,12 @@
 @contextmanager
 def recording_disabled():
     tls = appmap_tls()
+    original_value = tls.get("instrumentation_disabled")
     tls["instrumentation_disabled"] = True
     try:
         yield
     finally:
-        tls["instrumentation_disabled"] = False
+        tls["instrumentation_disabled"] = original_value
 
 
 def is_instrumentation_disabled():

_appmap/test/data/example_class.py

@@ -110,6 +110,9 @@ def with_docstring(self):
     def with_comment(self):
         return True
 
+    def return_self(self):
+        return self
+
 
 def modfunc():
     return "Hello world!"

_appmap/test/test_events.py

@@ -105,3 +105,15 @@ def test_when_display_disabled(self, mocker):
             # MagicMock. (If it's broken, we may not get here at all,
             # because the assertion above may fail.)
             param.__repr__.assert_called_once_with()
+
+    def test_describe_return_value_recursion_protection(self):
+        r = appmap.Recording()
+        with r:
+            # pylint: disable=import-outside-toplevel
+            from example_class import ExampleClass
+
+            ExampleClass().return_self()
+        # There should be no event for method another_method which is called by __repr__.
+        assert [e.method_id for e in r.events if e.event == "call" and hasattr(e, "method_id")] == [
+            "return_self"
+        ]