diff --git a/Include/objimpl.h b/Include/objimpl.h index b577be2df3b..8f36360bbf2 100644 --- a/Include/objimpl.h +++ b/Include/objimpl.h @@ -232,6 +232,10 @@ PyAPI_FUNC(PyVarObject *) _PyObject_NewVar(PyTypeObject *, Py_ssize_t); /* C equivalent of gc.collect(). */ PyAPI_FUNC(Py_ssize_t) PyGC_Collect(void); +#ifndef Py_LIMITED_API +PyAPI_FUNC(Py_ssize_t) _PyGC_CollectNoFail(void); +#endif + /* Test if a type has a GC head */ #define PyType_IS_GC(t) PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC) diff --git a/Misc/NEWS b/Misc/NEWS index 2bc763f99aa..a85bc9490c7 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -10,6 +10,8 @@ What's New in Python 3.4.0 Alpha 1? Core and Builtins ----------------- +- Issue #17937: Try harder to collect cyclic garbage at shutdown. + - Issue #12370: Prevent class bodies from interfering with the __class__ closure. diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c index 4315d55dcdb..28417c28fe5 100644 --- a/Modules/gcmodule.c +++ b/Modules/gcmodule.c @@ -853,7 +853,8 @@ get_time(void) /* This is the main function. Read this to understand how the * collection process works. */ static Py_ssize_t -collect(int generation, Py_ssize_t *n_collected, Py_ssize_t *n_uncollectable) +collect(int generation, Py_ssize_t *n_collected, Py_ssize_t *n_uncollectable, + int nofail) { int i; Py_ssize_t m = 0; /* # objects collected */ @@ -1000,10 +1001,15 @@ collect(int generation, Py_ssize_t *n_collected, Py_ssize_t *n_uncollectable) } if (PyErr_Occurred()) { - if (gc_str == NULL) - gc_str = PyUnicode_FromString("garbage collection"); - PyErr_WriteUnraisable(gc_str); - Py_FatalError("unexpected exception during garbage collection"); + if (nofail) { + PyErr_Clear(); + } + else { + if (gc_str == NULL) + gc_str = PyUnicode_FromString("garbage collection"); + PyErr_WriteUnraisable(gc_str); + Py_FatalError("unexpected exception during garbage collection"); + } } /* Update stats */ @@ -1062,7 +1068,7 @@ collect_with_callback(int generation) { Py_ssize_t result, collected, uncollectable; invoke_gc_callback("start", generation, 0, 0); - result = collect(generation, &collected, &uncollectable); + result = collect(generation, &collected, &uncollectable, 0); invoke_gc_callback("stop", generation, collected, uncollectable); return result; } @@ -1544,6 +1550,19 @@ PyGC_Collect(void) return n; } +Py_ssize_t +_PyGC_CollectNoFail(void) +{ + Py_ssize_t n; + + /* This function should only be called on interpreter shutdown, and + therefore not recursively. */ + assert(!collecting); + collecting = 1; + n = collect(NUM_GENERATIONS - 1, NULL, NULL, 1); + collecting = 0; + return n; +} void _PyGC_DumpShutdownStats(void) diff --git a/Python/import.c b/Python/import.c index 1fbafecc1b7..a42b0f89b0a 100644 --- a/Python/import.c +++ b/Python/import.c @@ -444,6 +444,7 @@ PyImport_Cleanup(void) /* Finally, clear and delete the modules directory */ PyDict_Clear(modules); + _PyGC_CollectNoFail(); interp->modules = NULL; Py_DECREF(modules); }