This prevents tests from failing when run from a Python installed in a
read-only directory.

The changed behavior of sdist in 3.1 broke packaging for projects that
wanted to use a manually-maintained MANIFEST file (instead of having a
MANIFEST.in template and letting distutils generate the MANIFEST).

The fixes that were committed for #8688 (76643c286b9f by Tarek and
d54da9248ed9 by me) did not fix all issues exposed in the bug report,
and also added one problem: the MANIFEST file format gained comments,
but the read_manifest method was not updated to handle (i.e. ignore)
them.  This changeset should fix everything; the tests have been
expanded and I successfully tested the 2.7 version with Mercurial, which
suffered from this regression.

I have grouped the versionchanged directives for these bugs in one place
and added micro version numbers to help users know the quirks of the
exact version they’re using.

Initial report, thorough diagnosis and patch by John Dennis, further
work on the patch by Stephen Thorne, and a few edits and additions by
me.

with the `-m` (or `--match`) option.  This works with all test cases
using the unittest module.  This is useful with long test suites
such as test_io or test_subprocess.

fix it. Patch by Petri Lehtinen.

importlib.import_module eschews a number of issues that __import__ has.
Reviewed by Brett Cannon.  (The docstring of __import__ was already
updated in 3d490c3a019e, for #7397.)

Issue #12644: document the '%a' conversion in the old string formatting operations. Patch prepared together with Ezio Melotti

Also remove an extra docstring.

Adding Sandro Tosi to Doc/ACKS for this patch and all his work on the
docs mailing list and on the bug tracker.

R. David Murray and I think that it’s more useful to have these files
show up in the output of “hg status”, to let the user know that some
merged file have to be checked before commit.  If you want to ignore
these files in your clones, it’s possible to do so from another ignore
file; see the bug report for directions.

I’m leaving the .gitignore file alone, as I don’t know how git users
work with merges and conflicts.

Fix closes Issue11439 Remove the SVN keywords from the code as it is no longer applicable in hg. Patch Contributed by Neil Muller.

to avoid timing-dependent failures.

given as a low fd, it gets overwritten.