tests/test-mailmap.t

make: switch the PYTHON default to `py.exe -3` on Windows

Python3 _is_ named `python.exe` on Windows, but that isn't necessarily on PATH
when installing from python.org.  I do happen to have a python.exe on PATH in
`$LOCALAPPDATA/Microsoft/WindowsApps`, but it appears to be 0 bytes (likely
because of permission issues), and doesn't run:

    $ python -V
     - Cannot open

Pulkit hit the same error as I did though, so it isn't just my system:

    $ make -C . local
    make: Entering directory `/home/Dell/repos/hg-committed`
    python setup.py  \
              build_py -c -d . \
              build_ext  -i \
              build_hgexe  -i \
              build_mo
     - Cannot openmake: *** [local] Error 1

The `py.exe` dispatcher lives in the Windows directory (so it is on PATH), looks
up the python.org installation, and invokes that interpreter directly.  I get a
warning with py39, but if it's our issue, it was an existing one:

    $ make -C .. local
    make: Entering directory `/c/Users/Matt/hg'
    py -3 setup.py  \
              build_py -c -d . \
              build_ext  -i \
              build_hgexe  -i \
              build_mo
    C:\Users\Matt\AppData\Local\Programs\Python\Python39\lib\site-packages\setuptools\distutils_patch.py:25:
        UserWarning: Distutils was imported before Setuptools. This usage is discouraged and may
        exhibit undesirable behaviors or errors. Please use Setuptools' objects directly or at least
        import Setuptools first.
      warnings.warn(

The end result is a py3 based hg.exe that annoyingly won't run because it can't
find python39.dll.  It will run tests (the ones without the `python3` shbang
line anyway), because the test runner adjusts PATH to include the python running
it.

Differential Revision: https://phab.mercurial-scm.org/D9361

Create a repo and add some commits

  $ hg init mm
  $ cd mm
  $ echo "Test content" > testfile1
  $ hg add testfile1
  $ hg commit -m "First commit" -u "Proper <commit@m.c>"
  $ echo "Test content 2" > testfile2
  $ hg add testfile2
  $ hg commit -m "Second commit" -u "Commit Name 2 <commit2@m.c>"
  $ echo "Test content 3" > testfile3
  $ hg add testfile3
  $ hg commit -m "Third commit" -u "Commit Name 3 <commit3@m.c>"
  $ echo "Test content 4" > testfile4
  $ hg add testfile4
  $ hg commit -m "Fourth commit" -u "Commit Name 4 <commit4@m.c>"

Add a .mailmap file with each possible entry type plus comments
  $ cat > .mailmap << EOF
  > # Comment shouldn't break anything
  > <proper@m.c> <commit@m.c> # Should update email only
  > Proper Name 2 <commit2@m.c> # Should update name only
  > Proper Name 3 <proper@m.c> <commit3@m.c> # Should update name, email due to email
  > Proper Name 4 <proper@m.c> Commit Name 4 <commit4@m.c> # Should update name, email due to name, email
  > EOF
  $ hg add .mailmap
  $ hg commit -m "Add mailmap file" -u "Testuser <test123@m.c>"

Output of commits should be normal without filter
  $ hg log -T "{author}\n" -r "all()"
  Proper <commit@m.c>
  Commit Name 2 <commit2@m.c>
  Commit Name 3 <commit3@m.c>
  Commit Name 4 <commit4@m.c>
  Testuser <test123@m.c>

Output of commits with filter shows their mailmap values
  $ hg log -T "{mailmap(author)}\n" -r "all()"
  Proper <proper@m.c>
  Proper Name 2 <commit2@m.c>
  Proper Name 3 <proper@m.c>
  Proper Name 4 <proper@m.c>
  Testuser <test123@m.c>

Add new mailmap entry for testuser
  $ cat >> .mailmap << EOF
  > <newmmentry@m.c> <test123@m.c>
  > EOF

Output of commits with filter shows their updated mailmap values
  $ hg log -T "{mailmap(author)}\n" -r "all()"
  Proper <proper@m.c>
  Proper Name 2 <commit2@m.c>
  Proper Name 3 <proper@m.c>
  Proper Name 4 <proper@m.c>
  Testuser <newmmentry@m.c>

A commit with improperly formatted user field should not break the filter
  $ echo "some more test content" > testfile1
  $ hg commit -m "Commit with improper user field" -u "Improper user"
  $ hg log -T "{mailmap(author)}\n" -r "all()"
  Proper <proper@m.c>
  Proper Name 2 <commit2@m.c>
  Proper Name 3 <proper@m.c>
  Proper Name 4 <proper@m.c>
  Testuser <newmmentry@m.c>
  Improper user

No TypeError beacause of invalid input

  $ hg log -T '{mailmap(termwidth)}\n' -r0
  80