view tests/test-close-head.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
author Simon Sapin <simon.sapin@octobus.net>
date Mon, 01 Mar 2021 20:36:06 +0100
parents fdd4d668ceb5
children
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  $ hg init test-content
  $ cd test-content
  $ hg debugbuilddag '+2*2*3*4+7'
  $ hg bookmark -r 1 @
  $ hg log -G --template '{rev}:{node|short}'
  o  11:1d876b1f862c
  |
  o  10:ea5f71948eb8
  |
  o  9:f1b0356d867a
  |
  o  8:e8d1253fb0d7
  |
  o  7:d423bbba4459
  |
  o  6:a2f58e9c1e56
  |
  o  5:3a367db1fabc
  |
  o  4:e7bd5218ca15
  |
  | o  3:6100d3090acf
  |/
  | o  2:fa942426a6fd
  |/
  | o  1:66f7d451a68b
  |/
  o  0:1ea73414a91b
  
  $ hg --config extensions.closehead= close-head -m 'Not a head' 0 1
  abort: revision is not an open head: 0
  [255]
  $ hg --config extensions.closehead= close-head -m 'Not a head' -r 0 1
  abort: revision is not an open head: 0
  [255]
  $ hg id
  000000000000
  $ hg --config extensions.closehead= close-head -m 'Close old heads' -r 1 2
  $ hg id
  000000000000
  $ hg bookmark
     @                         1:66f7d451a68b
  $ hg heads
  changeset:   11:1d876b1f862c
  user:        debugbuilddag
  date:        Thu Jan 01 00:00:11 1970 +0000
  summary:     r11
  
  changeset:   3:6100d3090acf
  parent:      0:1ea73414a91b
  user:        debugbuilddag
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     r3
  
  $ hg --config extensions.closehead= close-head -m 'Close more old heads' -r 11
  $ hg heads
  changeset:   3:6100d3090acf
  parent:      0:1ea73414a91b
  user:        debugbuilddag
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     r3
  
  $ hg --config extensions.closehead= close-head -m 'Not a head' 0
  abort: revision is not an open head: 0
  [255]
  $ hg --config extensions.closehead= close-head -m 'Already closed head' 1
  abort: revision is not an open head: 1
  [255]

  $ hg init ../test-empty
  $ cd ../test-empty
  $ hg debugbuilddag '+1'
  $ hg log -G --template '{rev}:{node|short}'
  o  0:1ea73414a91b
  
  $ hg --config extensions.closehead= close-head -m 'Close initial revision' 0
  $ hg heads
  [1]