view tests/test-merge-exec.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

===============================================
Testing merge involving change to the exec flag
===============================================

#require execbit


Initial setup
==============


  $ hg init base-repo
  $ cd base-repo
  $ cat << EOF > a
  > 1
  > 2
  > 3
  > 4
  > 5
  > 6
  > 7
  > 8
  > 9
  > EOF
  $ touch b
  $ hg add a b
  $ hg commit -m "initial commit"
  $ cd ..

  $ hg init base-exec
  $ cd base-exec
  $ cat << EOF > a
  > 1
  > 2
  > 3
  > 4
  > 5
  > 6
  > 7
  > 8
  > 9
  > EOF
  $ chmod +x a
  $ touch b
  $ hg add a b
  $ hg commit -m "initial commit"
  $ cd ..

Testing merging mode change
===========================

Adding the flag
---------------

setup

Change on one side, executable bit on the other

  $ hg clone base-repo simple-merge-repo
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd simple-merge-repo
  $ chmod +x a
  $ hg ci -m "make a executable, no change"
  $ [ -x a ] || echo "executable bit not recorded"
  $ hg up ".^"
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat << EOF > a
  > 1
  > 2
  > 3
  > 4
  > 5
  > 6
  > 7
  > x
  > 9
  > EOF
  $ hg commit -m "edit end of file"
  created new head

merge them (from the update side)

  $ hg merge 'desc("make a executable, no change")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st
  M a
  $ [ -x a ] || echo "executable bit lost"

merge them (from the chmod side)

  $ hg up -C 'desc("make a executable, no change")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg merge 'desc("edit end of file")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st
  M a
  $ [ -x a ] || echo "executable bit lost"


  $ cd ..


Removing the flag
-----------------

Change on one side, executable bit on the other

  $ hg clone base-exec simple-merge-repo-removal
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd simple-merge-repo-removal
  $ chmod -x a
  $ hg ci -m "make a non-executable, no change"
  $ [ -x a ] && echo "executable bit not removed"
  [1]
  $ hg up ".^"
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat << EOF > a
  > 1
  > 2
  > 3
  > 4
  > 5
  > 6
  > 7
  > x
  > 9
  > EOF
  $ hg commit -m "edit end of file"
  created new head

merge them (from the update side)

  $ hg merge 'desc("make a non-executable, no change")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st
  M a
  $ [ -x a ] && echo "executable bit not removed"
  [1]

merge them (from the chmod side)

  $ hg up -C 'desc("make a non-executable, no change")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg merge 'desc("edit end of file")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st
  M a
  $ [ -x a ] && echo "executable bit not removed"
  [1]


  $ cd ..

Testing merging mode change with rename
=======================================

Adding the flag
---------------

  $ hg clone base-repo rename-merge-repo
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd rename-merge-repo

make "a" executable on one side

  $ chmod +x a
  $ hg status
  M a
  $ hg ci -m "make a executable"
  $ [ -x a ] || echo "executable bit not recorded"
  $ hg up ".^"
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

make "a" renamed on the other side

  $ hg mv a z
  $ hg st --copies
  A z
    a
  R a
  $ hg ci -m "rename a to z"
  created new head

merge them (from the rename side)

  $ hg merge 'desc("make a executable")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st --copies
  M z
    a
  $ [ -x z ] || echo "executable bit lost"

merge them (from the chmod side)

  $ hg up -C 'desc("make a executable")'
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg merge 'desc("rename a to z")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st --copies
  M z
    a
  R a
  $ [ -x z ] || echo "executable bit lost"


  $ cd ..

Removing the flag
-----------------

  $ hg clone base-exec rename-merge-repo-removal
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd rename-merge-repo-removal

make "a" non-executable on one side

  $ chmod -x a
  $ hg status
  M a
  $ hg ci -m "make a non-executable"
  $ [ -x a ] && echo "executable bit not removed"
  [1]
  $ hg up ".^"
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

make "a" renamed on the other side

  $ hg mv a z
  $ hg st --copies
  A z
    a
  R a
  $ hg ci -m "rename a to z"
  created new head

merge them (from the rename side)

  $ hg merge 'desc("make a non-executable")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st --copies
  M z
    a
  $ [ -x z ] && echo "executable bit not removed"
  [1]

merge them (from the chmod side)

  $ hg up -C 'desc("make a non-executable")'
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg merge 'desc("rename a to z")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st --copies
  M z
    a
  R a
  $ [ -x z ] && echo "executable bit not removed"
  [1]


  $ cd ..


Testing merging mode change with rename + modification on both side
===================================================================


Adding the flag
---------------

  $ hg clone base-repo rename+mod-merge-repo
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd rename+mod-merge-repo

make "a" executable on one side

  $ chmod +x a
  $ cat << EOF > a
  > 1
  > x
  > 3
  > 4
  > 5
  > 6
  > 7
  > 8
  > 9
  > EOF
  $ hg status
  M a
  $ hg ci -m "make a executable, and change start"
  $ [ -x a ] || echo "executable bit not recorded"
  $ hg up ".^"
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

make "a" renamed on the other side

  $ hg mv a z
  $ hg st --copies
  A z
    a
  R a
  $ cat << EOF > z
  > 1
  > 2
  > 3
  > 4
  > 5
  > 6
  > 7
  > x
  > 9
  > EOF
  $ hg ci -m "rename a to z, and change end"
  created new head

merge them (from the rename side)

  $ hg merge 'desc("make a executable")'
  merging z and a to z
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st --copies
  M z
    a
  $ [ -x z ] || echo "executable bit lost"

merge them (from the chmod side)

  $ hg up -C 'desc("make a executable")'
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg merge 'desc("rename a to z")'
  merging a and z to z
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st --copies
  M z
    a
  R a
  $ [ -x z ] || echo "executable bit lost"

  $ cd ..

Removing the flag
-----------------

  $ hg clone base-exec rename+mod-merge-repo-removal
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd rename+mod-merge-repo-removal

make "a" non-executable on one side

  $ chmod -x a
  $ cat << EOF > a
  > 1
  > x
  > 3
  > 4
  > 5
  > 6
  > 7
  > 8
  > 9
  > EOF
  $ hg status
  M a
  $ hg ci -m "make a non-executable, and change start"
  $ [ -x z ] && echo "executable bit not removed"
  [1]
  $ hg up ".^"
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

make "a" renamed on the other side

  $ hg mv a z
  $ hg st --copies
  A z
    a
  R a
  $ cat << EOF > z
  > 1
  > 2
  > 3
  > 4
  > 5
  > 6
  > 7
  > x
  > 9
  > EOF
  $ hg ci -m "rename a to z, and change end"
  created new head

merge them (from the rename side)

  $ hg merge 'desc("make a non-executable")'
  merging z and a to z
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st --copies
  M z
    a
  $ [ -x z ] && echo "executable bit not removed"
  [1]

merge them (from the chmod side)

  $ hg up -C 'desc("make a non-executable")'
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg merge 'desc("rename a to z")'
  merging a and z to z
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg st --copies
  M z
    a
  R a
  $ [ -x z ] && echo "executable bit not removed"
  [1]

  $ cd ..