view tests/test-status-rev.t @ 46667:93e9f448273c

rhg: Add support for automatic fallback to Python

`rhg` is a command-line application that can do a small subset of what
`hg` can. It is written entirely in Rust, which avoids the cost of starting
a Python interpreter and importing many Python modules.
In a script that runs many `hg` commands, this cost can add up.

However making users decide when to use `rhg` instead of `hg` is
not practical as we want the subset of supported functionality
to grow over time.

Instead we introduce "fallback" behavior where, when `rhg` encounters
something (a sub-command, a repository format, …) that is not implemented
in Rust-only, it does nothing but silently start a subprocess of
Python-based `hg` running the same command.
That way `rhg` becomes a drop-in replacement for `hg` that sometimes
goes faster. Whether Python is used should be an implementation detail
not apparent to users (other than through speed).

A new `fallback` value is added to the previously introduced
`rhg.on-unsupported` configuration key. When in this mode, the new
`rhg.fallback-executable` config is determine what command to use
to run a Python-based `hg`.

The previous `rhg.on-unsupported = abort-silent` configuration was designed
to let a wrapper script call `rhg` and then fall back to `hg` based on the
exit code. This is still available, but having fallback behavior built-in
in rhg might be easier for users instead of leaving that script "as an
exercise for the reader".

Using a subprocess like this is not idea, especially when `rhg` is to be
installed in `$PATH` as `hg`, since the other `hg.py` executable needs
to still be available… somewhere. Eventually this could be replaced
by using PyOxidizer to a have a single executable that embeds a Python
interpreter, but only starts it when needed.

Differential Revision: https://phab.mercurial-scm.org/D10093

Tests of 'hg status --rev <rev>' to make sure status between <rev> and '.' get
combined correctly with the dirstate status.

  $ hg init

First commit

  $ "$PYTHON" $TESTDIR/generate-working-copy-states.py state 2 1
  $ hg addremove --similarity 0
  adding content1_content1_content1-tracked
  adding content1_content1_content1-untracked
  adding content1_content1_content3-tracked
  adding content1_content1_content3-untracked
  adding content1_content1_missing-tracked
  adding content1_content1_missing-untracked
  adding content1_content2_content1-tracked
  adding content1_content2_content1-untracked
  adding content1_content2_content2-tracked
  adding content1_content2_content2-untracked
  adding content1_content2_content3-tracked
  adding content1_content2_content3-untracked
  adding content1_content2_missing-tracked
  adding content1_content2_missing-untracked
  adding content1_missing_content1-tracked
  adding content1_missing_content1-untracked
  adding content1_missing_content3-tracked
  adding content1_missing_content3-untracked
  adding content1_missing_missing-tracked
  adding content1_missing_missing-untracked
  $ hg commit -m first

Second commit

  $ "$PYTHON" $TESTDIR/generate-working-copy-states.py state 2 2
  $ hg addremove --similarity 0
  removing content1_missing_content1-tracked
  removing content1_missing_content1-untracked
  removing content1_missing_content3-tracked
  removing content1_missing_content3-untracked
  removing content1_missing_missing-tracked
  removing content1_missing_missing-untracked
  adding missing_content2_content2-tracked
  adding missing_content2_content2-untracked
  adding missing_content2_content3-tracked
  adding missing_content2_content3-untracked
  adding missing_content2_missing-tracked
  adding missing_content2_missing-untracked
  $ hg commit -m second

Working copy

  $ "$PYTHON" $TESTDIR/generate-working-copy-states.py state 2 wc
  $ hg addremove --similarity 0
  adding content1_missing_content1-tracked
  adding content1_missing_content1-untracked
  adding content1_missing_content3-tracked
  adding content1_missing_content3-untracked
  adding content1_missing_missing-tracked
  adding content1_missing_missing-untracked
  adding missing_missing_content3-tracked
  adding missing_missing_content3-untracked
  adding missing_missing_missing-tracked
  adding missing_missing_missing-untracked
  $ hg forget *_*_*-untracked
  $ rm *_*_missing-*

Status compared to parent of the working copy, i.e. the dirstate status

  $ hg status -A --rev 1 'glob:missing_content2_content3-tracked'
  M missing_content2_content3-tracked
  $ hg status -A --rev 1 'glob:missing_content2_content2-tracked'
  C missing_content2_content2-tracked
  $ hg status -A --rev 1 'glob:missing_missing_content3-tracked'
  A missing_missing_content3-tracked
  $ hg status -A --rev 1 'glob:missing_missing_content3-untracked'
  ? missing_missing_content3-untracked
  $ hg status -A --rev 1 'glob:missing_content2_*-untracked'
  R missing_content2_content2-untracked
  R missing_content2_content3-untracked
  R missing_content2_missing-untracked
  $ hg status -A --rev 1 'glob:missing_*_missing-tracked'
  ! missing_content2_missing-tracked
  ! missing_missing_missing-tracked

  $ hg status -A --rev 1 'glob:missing_missing_missing-untracked'
  missing_missing_missing-untracked: $ENOENT$

Status between first and second commit. Should ignore dirstate status.

  $ hg status -A --rev 0:1 'glob:content1_content2_*'
  M content1_content2_content1-tracked
  M content1_content2_content1-untracked
  M content1_content2_content2-tracked
  M content1_content2_content2-untracked
  M content1_content2_content3-tracked
  M content1_content2_content3-untracked
  M content1_content2_missing-tracked
  M content1_content2_missing-untracked
  $ hg status -A --rev 0:1 'glob:content1_content1_*'
  C content1_content1_content1-tracked
  C content1_content1_content1-untracked
  C content1_content1_content3-tracked
  C content1_content1_content3-untracked
  C content1_content1_missing-tracked
  C content1_content1_missing-untracked
  $ hg status -A --rev 0:1 'glob:missing_content2_*'
  A missing_content2_content2-tracked
  A missing_content2_content2-untracked
  A missing_content2_content3-tracked
  A missing_content2_content3-untracked
  A missing_content2_missing-tracked
  A missing_content2_missing-untracked
  $ hg status -A --rev 0:1 'glob:content1_missing_*'
  R content1_missing_content1-tracked
  R content1_missing_content1-untracked
  R content1_missing_content3-tracked
  R content1_missing_content3-untracked
  R content1_missing_missing-tracked
  R content1_missing_missing-untracked
  $ hg status -A --rev 0:1 'glob:missing_missing_*'

Status compared to one revision back, checking that the dirstate status
is correctly combined with the inter-revision status

  $ hg status -A --rev 0 'glob:content1_*_content[23]-tracked'
  M content1_content1_content3-tracked
  M content1_content2_content2-tracked
  M content1_content2_content3-tracked
  M content1_missing_content3-tracked
  $ hg status -A --rev 0 'glob:content1_*_content1-tracked'
  C content1_content1_content1-tracked
  C content1_content2_content1-tracked
  C content1_missing_content1-tracked
  $ hg status -A --rev 0 'glob:missing_*_content?-tracked'
  A missing_content2_content2-tracked
  A missing_content2_content3-tracked
  A missing_missing_content3-tracked
BROKEN: missing_content2_content[23]-untracked exist, so should be listed
  $ hg status -A --rev 0 'glob:missing_*_content?-untracked'
  ? missing_missing_content3-untracked
  $ hg status -A --rev 0 'glob:content1_*_*-untracked'
  R content1_content1_content1-untracked
  R content1_content1_content3-untracked
  R content1_content1_missing-untracked
  R content1_content2_content1-untracked
  R content1_content2_content2-untracked
  R content1_content2_content3-untracked
  R content1_content2_missing-untracked
  R content1_missing_content1-untracked
  R content1_missing_content3-untracked
  R content1_missing_missing-untracked
  $ hg status -A --rev 0 'glob:*_*_missing-tracked'
  ! content1_content1_missing-tracked
  ! content1_content2_missing-tracked
  ! content1_missing_missing-tracked
  ! missing_content2_missing-tracked
  ! missing_missing_missing-tracked
  $ hg status -A --rev 0 'glob:missing_*_missing-untracked'