tests/test-narrow-rebase.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

#testcases continuecommand continueflag
#if continueflag
  $ cat >> $HGRCPATH <<EOF
  > [alias]
  > continue = rebase --continue
  > EOF
#endif

  $ . "$TESTDIR/narrow-library.sh"

create full repo

  $ hg init master
  $ cd master

  $ mkdir inside
  $ echo inside1 > inside/f1
  $ echo inside2 > inside/f2
  $ mkdir outside
  $ echo outside1 > outside/f1
  $ echo outside2 > outside/f2
  $ hg ci -Aqm 'initial'

  $ echo modified > inside/f1
  $ hg ci -qm 'modify inside/f1'

  $ hg update -q 0
  $ echo modified2 > inside/f2
  $ hg ci -qm 'modify inside/f2'

  $ hg update -q 0
  $ echo modified > outside/f1
  $ hg ci -qm 'modify outside/f1'

  $ hg update -q 0
  $ echo modified2 > outside/f1
  $ hg ci -qm 'conflicting outside/f1'

  $ cd ..

  $ hg clone --narrow ssh://user@dummy/master narrow --include inside
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 4 changes to 2 files (+3 heads)
  new changesets *:* (glob)
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > EOF

  $ hg update -q 0

Can rebase onto commit where no files outside narrow spec are involved

  $ hg update -q 0
  $ echo modified > inside/f2
  $ hg ci -qm 'modify inside/f2'
  $ hg rebase -d 'desc("modify inside/f1")'
  rebasing 5:c2f36d04e05d tip "modify inside/f2"
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-rebase.hg (glob)

Can rebase onto conflicting changes inside narrow spec

  $ hg update -q 0
  $ echo conflicting > inside/f1
  $ hg ci -qm 'conflicting inside/f1'
  $ hg rebase -d 'desc("modify inside/f1")' 2>&1 | egrep -v '(warning:|incomplete!)'
  rebasing 6:cdce97fbf653 tip "conflicting inside/f1"
  merging inside/f1
  unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
  $ echo modified3 > inside/f1
  $ hg resolve -m 2>&1 | grep -v continue:
  (no more unresolved files)
  $ hg continue
  rebasing 6:cdce97fbf653 tip "conflicting inside/f1"
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-rebase.hg (glob)

Can rebase onto non-conflicting changes outside narrow spec

  $ hg update -q 0
  $ echo modified > inside/f2
  $ hg ci -qm 'modify inside/f2'
  $ hg rebase -d 'desc("modify outside/f1")'
  rebasing 7:c2f36d04e05d tip "modify inside/f2"
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-rebase.hg (glob)

Rebase interrupts on conflicting changes outside narrow spec

  $ hg update -q 'desc("conflicting outside/f1")'
  $ hg phase -f -d .
  $ hg rebase -d 'desc("modify outside/f1")'
  rebasing 4:707c035aadb6 "conflicting outside/f1"
  abort: conflict in file 'outside/f1' is outside narrow clone
  [255]