fix(scope): Handle token reset LookupErrors gracefully (#4481)

We're surfacing internal SDK errors to users in
#4410.

Author: sentrivana

sentry_sdk/scope.py

@@ -1673,8 +1673,11 @@ def new_scope():
         yield new_scope
 
     finally:
-        # restore original scope
-        _current_scope.reset(token)
+        try:
+            # restore original scope
+            _current_scope.reset(token)
+        except LookupError:
+            capture_internal_exception(sys.exc_info())
 
 
 @contextmanager
@@ -1708,8 +1711,11 @@ def use_scope(scope):
         yield scope
 
     finally:
-        # restore original scope
-        _current_scope.reset(token)
+        try:
+            # restore original scope
+            _current_scope.reset(token)
+        except LookupError:
+            capture_internal_exception(sys.exc_info())
 
 
 @contextmanager
@@ -1750,8 +1756,15 @@ def isolation_scope():
 
     finally:
         # restore original scopes
-        _current_scope.reset(current_token)
-        _isolation_scope.reset(isolation_token)
+        try:
+            _current_scope.reset(current_token)
+        except LookupError:
+            capture_internal_exception(sys.exc_info())
+
+        try:
+            _isolation_scope.reset(isolation_token)
+        except LookupError:
+            capture_internal_exception(sys.exc_info())
 
 
 @contextmanager
@@ -1790,8 +1803,15 @@ def use_isolation_scope(isolation_scope):
 
     finally:
         # restore original scopes
-        _current_scope.reset(current_token)
-        _isolation_scope.reset(isolation_token)
+        try:
+            _current_scope.reset(current_token)
+        except LookupError:
+            capture_internal_exception(sys.exc_info())
+
+        try:
+            _isolation_scope.reset(isolation_token)
+        except LookupError:
+            capture_internal_exception(sys.exc_info())
 
 
 def should_send_default_pii():

tests/test_scope.py

@@ -905,3 +905,67 @@ def test_last_event_id_cleared(sentry_init):
     Scope.get_isolation_scope().clear()
 
     assert Scope.last_event_id() is None, "last_event_id should be cleared"
+
+
+@pytest.mark.tests_internal_exceptions
+@pytest.mark.parametrize(
+    "scope_manager",
+    [
+        new_scope,
+        use_scope,
+    ],
+)
+def test_handle_lookup_error_on_token_reset_current_scope(scope_manager):
+    with mock.patch("sentry_sdk.scope.capture_internal_exception") as mock_capture:
+        with mock.patch("sentry_sdk.scope._current_scope") as mock_token_var:
+            mock_token_var.reset.side_effect = LookupError()
+
+            mock_token = mock.Mock()
+            mock_token_var.set.return_value = mock_token
+
+            try:
+                if scope_manager == use_scope:
+                    with scope_manager(Scope()):
+                        pass
+                else:
+                    with scope_manager():
+                        pass
+
+            except Exception:
+                pytest.fail("Context manager should handle LookupError gracefully")
+
+            mock_capture.assert_called_once()
+            mock_token_var.reset.assert_called_once_with(mock_token)
+
+
+@pytest.mark.tests_internal_exceptions
+@pytest.mark.parametrize(
+    "scope_manager",
+    [
+        isolation_scope,
+        use_isolation_scope,
+    ],
+)
+def test_handle_lookup_error_on_token_reset_isolation_scope(scope_manager):
+    with mock.patch("sentry_sdk.scope.capture_internal_exception") as mock_capture:
+        with mock.patch("sentry_sdk.scope._current_scope") as mock_current_scope:
+            with mock.patch(
+                "sentry_sdk.scope._isolation_scope"
+            ) as mock_isolation_scope:
+                mock_isolation_scope.reset.side_effect = LookupError()
+                mock_current_token = mock.Mock()
+                mock_current_scope.set.return_value = mock_current_token
+
+                try:
+                    if scope_manager == use_isolation_scope:
+                        with scope_manager(Scope()):
+                            pass
+                    else:
+                        with scope_manager():
+                            pass
+
+                except Exception:
+                    pytest.fail("Context manager should handle LookupError gracefully")
+
+                mock_capture.assert_called_once()
+                mock_current_scope.reset.assert_called_once_with(mock_current_token)