gh-135335: Simplify preload regression test using __main__ (GH-138686)
Simplify preload regression test using `__main__`
With the fix for gh-126631 `__main__` modules can be preloaded and the regression
test for gh-135335 can be simplified to just use a self-contained script rather
than requiring a module.
Note this assumes and implicitly tests that `__main__` is preloaded by default.
(cherry picked from commit 425f24e4fa)
Co-authored-by: Duane Griffin <duaneg@dghda.com>
gh-135335: flush stdout/stderr in forkserver after preloading modules (GH-135338)
If a preloaded module writes to stdout or stderr, and the stream is buffered,
child processes will inherit the buffered data after forking. Attempt to
prevent this by flushing the streams after preload.
(cherry picked from commit 9877d191f4)
Co-authored-by: Duane Griffin <duaneg@dghda.com>
Co-authored-by: Mikhail Efimov <efimov.mikhail@gmail.com>
Co-authored-by: Victor Stinner <vstinner@python.org>
