PEP 489: Multi-phase extension module initialization

Known limitations of the current implementation:

- documentation changes are incomplete
- there's a reference leak I haven't tracked down yet

The leak is most visible by running:

  ./python -m test -R3:3 test_importlib

However, you can also see it by running:

  ./python -X showrefcount

Importing the array or _testmultiphase modules, and
then deleting them from both sys.modules and the local
namespace shows significant increases in the total
number of active references each cycle. By contrast,
with _testcapi (which continues to use single-phase
initialisation) the global refcounts stabilise after
a couple of cycles.

1 files changed, 3 insertions, 0 deletions

diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index 77167b2c1e..1967686624 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -4048,6 +4048,9 @@ static struct PyModuleDef _testcapimodule = {
     NULL
 };
 
+/* Per PEP 489, this module will not be converted to multi-phase initialization
+ */
+
 PyMODINIT_FUNC
 PyInit__testcapi(void)
 {