This PR adds the ability to enable the GIL if it was disabled at
interpreter startup, and modifies the multi-phase module initialization
path to enable the GIL when loading a module, unless that module's spec
includes a slot indicating it can run safely without the GIL.
PEP 703 called the constant for the slot `Py_mod_gil_not_used`; I went
with `Py_MOD_GIL_NOT_USED` for consistency with gh-104148.
A warning will be issued up to once per interpreter for the first
GIL-using module that is loaded. If `-v` is given, a shorter message
will be printed to stderr every time a GIL-using module is loaded
(including the first one that issues a warning).
Add basic fuzz tests for a few common builtin functions.
This is an easy place to start, and these functions are probably safe.
We'll want to add more fuzz tests later. Lets bootstrap using these.
While the fuzz tests are included in CPython and compiled / tested on a
very basic level inside CPython itself, the actual fuzzing happens as
part of oss-fuzz (https://github.com/google/oss-fuzz). The reason to
include the tests in CPython is to make sure that they're maintained
as part of the CPython project, especially when (as some eventually
will) they use internal implementation details in the test.
(This will be necessary sometimes because e.g. the fuzz test should
never enter Python's interpreter loop, whereas some APIs only expose
themselves publicly as Python functions.)
This particular set of changes is part of testing Python's builtins,
tracked internally at Google by b/37562550.
The _xxtestfuzz module that this change adds need not be shipped with binary distributions of Python.
Brett Simmers
Inada Naoki
Brandt Bucher
Devin Jeanpierre