diff options
| -rw-r--r-- | Misc/NEWS | 10 | ||||
| -rw-r--r-- | Python/pythonrun.c | 29 |
2 files changed, 37 insertions, 2 deletions
@@ -12,6 +12,16 @@ What's New in Python 2.4 alpha 1? Core and builtins ----------------- +- At Python shutdown time (Py_Finalize()), 2.3 called cyclic garbage + collection twice, both before and after tearing down modules. The + call after tearing down modules has been disabled, because too much + of Python has been torn down then for __del__ methods and weakref + callbacks to execute sanely. The most common symptom was a sequence + of uninformative messages on stderr when Python shut down, produced + by threads trying to raise exceptions, but unable to report the nature + of their problems because too much of the sys module had already been + destroyed. + - Removed FutureWarnings related to hex/oct literals and conversions and left shifts. (Thanks to Kalle Svensson for SF patch 849227.) This addresses most of the remaining semantic changes promised by diff --git a/Python/pythonrun.c b/Python/pythonrun.c index ed54ab3..eedb562 100644 --- a/Python/pythonrun.c +++ b/Python/pythonrun.c @@ -329,15 +329,40 @@ Py_Finalize(void) warnings_module = NULL; /* Collect garbage. This may call finalizers; it's nice to call these - before all modules are destroyed. */ + * before all modules are destroyed. + * XXX If a __del__ or weakref callback is triggered here, and tries to + * XXX import a module, bad things can happen, because Python no + * XXX longer believes it's initialized. + * XXX Fatal Python error: Interpreter not initialized (version mismatch?) + * XXX is easy to provoke that way. I've also seen, e.g., + * XXX Exception exceptions.ImportError: 'No module named sha' + * XXX in <function callback at 0x008F5718> ignored + * XXX but I'm unclear on exactly how that one happens. In any case, + * XXX I haven't seen a real-life report of either of these. + */ PyGC_Collect(); /* Destroy all modules */ PyImport_Cleanup(); /* Collect final garbage. This disposes of cycles created by - new-style class definitions, for example. */ + * new-style class definitions, for example. + * XXX This is disabled because it caused too many problems. If + * XXX a __del__ or weakref callback triggers here, Python code has + * XXX a hard time running, because even the sys module has been + * XXX cleared out (sys.stdout is gone, sys.excepthook is gone, etc). + * XXX One symptom is a sequence of information-free messages + * XXX coming from threads (if a __del__ or callback is invoked, + * XXX other threads can execute too, and any exception they encounter + * XXX triggers a comedy of errors as subsystem after subsystem + * XXX fails to find what it *expects* to find in sys to help report + * XXX the exception and consequent unexpected failures). I've also + * XXX seen segfaults then, after adding print statements to the + * XXX Python code getting called. + */ +#if 0 PyGC_Collect(); +#endif /* Destroy the database used by _PyImport_{Fixup,Find}Extension */ _PyImport_Fini(); |