When an unawaited coroutine is collected very late in shutdown --
like, during the final GC at the end of PyImport_Cleanup -- then it
was triggering an interpreter abort, because we'd try to look up the
"warnings" module and not only was it missing (we were prepared for
that), but the entire module system was missing (which we were not
prepared for).
I've tried to fix this at the source, by making the utility function
get_warnings_attr robust against this in general. Note that it already
has the convention that it can return NULL without setting an error,
which is how it signals that the attribute it was asked to fetch is
missing, and that all callers already check for NULL returns.
There's a similar check for being late in shutdown at the top of
warn_explicit, which might be unnecessary after this fix, but I'm not
sure so I'm going to leave it..
(cherry picked from commit dba976b8a2)
Co-authored-by: Nathaniel J. Smith <njs@pobox.com>
Issue #26592: _warnings.warn_explicit() now tries to import the warnings module
(Python implementation) if the source parameter is set to be able to log the
traceback where the source was allocated.
Issue #26604:
* Add a new optional source parameter to _warnings.warn() and warnings.warn()
* Modify asyncore, asyncio and _pyio modules to set the source parameter when
logging a ResourceWarning warning
Issue #26567:
* Add a new function PyErr_ResourceWarning() function to pass the destroyed
object
* Add a source attribute to warnings.WarningMessage
* Add warnings._showwarnmsg() which uses tracemalloc to get the traceback where
source object was allocated.
Issue #26568: add new _showwarnmsg() and _formatwarnmsg() functions to the
warnings module.
The C function warn_explicit() now calls warnings._showwarnmsg() with a
warnings.WarningMessage as parameter, instead of calling warnings.showwarning()
with multiple parameters.
_showwarnmsg() calls warnings.showwarning() if warnings.showwarning() was
replaced. Same for _formatwarnmsg(): call warnings.formatwarning() if it was
replaced.
The concept of .pyo files no longer exists. Now .pyc files have an
optional `opt-` tag which specifies if any extra optimizations beyond
the peepholer were applied.
instead of creating temporary Unicode string objects
Add also more identifiers in pythonrun.c to avoid temporary Unicode string
objets for the interactive interpreter.
_Py_DisplaySourceLine()
For example, _PyGC_DumpShutdownStats() calls PyErr_WarnExplicitFormat() while
the import machinery does not work anymore, _Py_DisplaySourceLine() fails when
trying to import the io module.
