Keep direct closure of generators and coroutines intact during cleanup by...

Keep direct closure of generators and coroutines intact during cleanup by disabling their tp_clear() as they still need their closure for handling the final GeneratorExit call.

Cython/Compiler/ParseTreeTransforms.py

@@ -2660,6 +2660,9 @@ class CreateClosureClasses(CythonTransform):
         class_scope = entry.type.scope
         class_scope.is_internal = True
         class_scope.is_closure_class_scope = True
+        if node.is_async_def or node.is_generator:
+            # Generators need their closure intact during cleanup as they resume to handle GeneratorExit
+            class_scope.directives['no_gc_clear'] = True
         if Options.closure_freelist_size:
             class_scope.directives['freelist'] = Options.closure_freelist_size
 

tests/run/generator_frame_cycle.py

 # mode: run
 # tag: generator
 
+import cython
 import sys
 
 
@@ -24,6 +25,9 @@ def test_generator_frame_cycle():
     eval('g.throw(ValueError)', {'g': g})
     del g
 
+    if cython.compiled:
+        # FIXME: this should not be necessary, but I can't see how to do it...
+        import gc; gc.collect()
     return tuple(testit)
 
 
@@ -53,4 +57,7 @@ def test_generator_frame_cycle_with_outer_exc():
         del g
         assert sys.exc_info()[1] is exc, sys.exc_info()
 
+    if cython.compiled:
+        # FIXME: this should not be necessary, but I can't see how to do it...
+        import gc; gc.collect()
     return tuple(testit)