tests/test-basic.t

run-tests: stuff a `python3.exe` into the test bin directory on Windows

Windows doesn't have `python3.exe` as part of the python.org distribution, and
that broke every script with a shebang after c102b704edb5.  Windows itself
provides a `python3.exe` app execution alias[1], but it is some sort of reparse
point that MSYS is incapable of handling[2].  When run by MSYS, it simply prints

    $ python3 -V
     - Cannot open

That in turn caused every `hghave` check, and test that invokes shebang scripts
directly, to fail.  Rather than try to patch up every script call to be invoked
with `$PYTHON` (and regress when non Windows developers forget), copying the
executable into the test binary directory with the new name just works.  Since
this directory is prepended to the system PATH value, it also overrides the
broken execution alias.  (The `_tmpbindir` is used instead of `_bindir` because
the latter causes python3.exe to be copied into the repo next to hg.exe when
`test-run-tests.t` runs.  Something runs with this version of the executable and
subsequent runs of `run-tests.py` inside `test-run-tests.t` try to copy over it
while it is in use, and fail.  This avoids the failures and the clutter.)

I didn't conditionalize this on py3 because `python3.exe` needs to be present
(for the shebangs) even when running py2 tests.  It shouldn't matter to these
simple scripts, and I think the intention is to make the test runner use py3
always, even if testing a py2 build.  For now, still supporting py2 is helping
to clean up the mess that is py3 tests.

[1] https://stackoverflow.com/a/57168165
[2] https://stackoverflow.com/questions/59148628/solved-unable-to-run-python-3-7-on-windows-10-permission-denied#comment104524397_59148666

Differential Revision: https://phab.mercurial-scm.org/D9543

Create a repository:

#if no-extraextensions
  $ hg config
  devel.all-warnings=true
  devel.default-date=0 0
  extensions.fsmonitor= (fsmonitor !)
  largefiles.usercache=$TESTTMP/.cache/largefiles
  lfs.usercache=$TESTTMP/.cache/lfs
  ui.slash=True
  ui.interactive=False
  ui.detailed-exit-code=True
  ui.merge=internal:merge
  ui.mergemarkers=detailed
  ui.promptecho=True
  ui.timeout.warn=15
  web.address=localhost
  web\.ipv6=(?:True|False) (re)
  web.server-header=testing stub value
#endif

  $ hg init t
  $ cd t

Prepare a changeset:

  $ echo a > a
  $ hg add a

  $ hg status
  A a

Writes to stdio succeed and fail appropriately

#if devfull
  $ hg status 2>/dev/full
  A a

  $ hg status >/dev/full
  abort: No space left on device
  [255]
#endif

#if devfull
  $ hg status >/dev/full 2>&1
  [255]

  $ hg status ENOENT 2>/dev/full
  [255]
#endif

  $ hg commit -m test

This command is ancient:

  $ hg history
  changeset:   0:acb14030fe0a
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     test
  

Verify that updating to revision 0 via commands.update() works properly

  $ cat <<EOF > update_to_rev0.py
  > from mercurial import commands, hg, ui as uimod
  > myui = uimod.ui.load()
  > repo = hg.repository(myui, path=b'.')
  > commands.update(myui, repo, rev=b"0")
  > EOF
  $ hg up null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ "$PYTHON" ./update_to_rev0.py
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg identify -n
  0


Poke around at hashes:

  $ hg manifest --debug
  b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 644   a

  $ hg cat a
  a

Verify should succeed:

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 1 changes to 1 files

Repository root:

  $ hg root
  $TESTTMP/t
  $ hg log -l1 -T '{reporoot}\n'
  $TESTTMP/t
  $ hg root -Tjson | sed 's|\\\\|\\|g'
  [
   {
    "hgpath": "$TESTTMP/t/.hg",
    "reporoot": "$TESTTMP/t",
    "storepath": "$TESTTMP/t/.hg/store"
   }
  ]

At the end...

  $ cd ..

Status message redirection:

  $ hg init empty

 status messages are sent to stdout by default:

  $ hg outgoing -R t empty -Tjson 2>/dev/null
  comparing with empty
  searching for changes
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]

 which can be configured to send to stderr, so the output wouldn't be
 interleaved:

  $ cat <<'EOF' >> "$HGRCPATH"
  > [ui]
  > message-output = stderr
  > EOF
  $ hg outgoing -R t empty -Tjson 2>/dev/null
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]
  $ hg outgoing -R t empty -Tjson >/dev/null
  comparing with empty
  searching for changes

 this option should be turned off by HGPLAIN= since it may break scripting use:

  $ HGPLAIN= hg outgoing -R t empty -Tjson 2>/dev/null
  comparing with empty
  searching for changes
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]

 but still overridden by --config:

  $ HGPLAIN= hg outgoing -R t empty -Tjson --config ui.message-output=stderr \
  > 2>/dev/null
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]

Invalid ui.message-output option:

  $ hg log -R t --config ui.message-output=bad
  abort: invalid ui.message-output destination: bad
  [255]

Underlying message streams should be updated when ui.fout/ferr are set:

  $ cat <<'EOF' > capui.py
  > from mercurial import pycompat, registrar
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'capui', norepo=True)
  > def capui(ui):
  >     out = ui.fout
  >     ui.fout = pycompat.bytesio()
  >     ui.status(b'status\n')
  >     ui.ferr = pycompat.bytesio()
  >     ui.warn(b'warn\n')
  >     out.write(b'stdout: %s' % ui.fout.getvalue())
  >     out.write(b'stderr: %s' % ui.ferr.getvalue())
  > EOF
  $ hg --config extensions.capui=capui.py --config ui.message-output=stdio capui
  stdout: status
  stderr: warn