After the patch (45590) to add extra debug stats to the gc module, Python
was crashing on OpenBSD due to:
Fatal Python error: Interpreter not initialized (version mismatch?)
This seems to occur due to calling collect() when initialized (in pythonrun.c)
is set to 0. Now, the import will occur in the init function which
shouldn't suffer this problem.
that are suspended outside of any try/except/finally blocks to be
garbage collected even if they are part of a cycle. Generators that
suspend inside of an active try/except or try/finally block (including
those created by a ``with`` statement) are still not GC-able if they
are part of a cycle, however.
nothing in gc currently cares, the original coding could screw up if,
e.g., you tried to move a node to the list it's already in, and the node
was already the last in its list.
Introduced gc_list_move(), which captures the common gc_list_remove() +
gc_list_append() sequence. In fact, no uses of gc_list_append() remained
(they were all in a gc_list_move() sequence), so commented that one out.
gc_list_merge(): assert that `from` != `to`; that was an implicit
precondition, now verified in a debug build.
Others: added comments about their purpose.
In cyclic gc, clear weakrefs to unreachable objects before allowing any
Python code (weakref callbacks or __del__ methods) to run.
This is a critical bugfix, affecting all versions of Python since weakrefs
were introduced. I'll backport to 2.3.
