Mercurial > hg
view tests/svn/encoding.svndump @ 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 | 0332f8b44e54 |
| children |
line wrap: on
line source
SVN-fs-dump-format-version: 2 UUID: afeb9c47-92ff-4c0c-9f72-e1f6eb8ac9af Revision-number: 0 Prop-content-length: 56 Content-length: 56 K 8 svn:date V 27 2009-06-21T16:34:55.835945Z PROPS-END Revision-number: 1 Prop-content-length: 112 Content-length: 112 K 7 svn:log V 10 init projA K 10 svn:author V 7 pmezard K 8 svn:date V 27 2009-06-21T16:34:55.909545Z PROPS-END Node-path: branches Node-kind: dir Node-action: add Prop-content-length: 10 Content-length: 10 PROPS-END Node-path: tags Node-kind: dir Node-action: add Prop-content-length: 10 Content-length: 10 PROPS-END Node-path: trunk Node-kind: dir Node-action: add Prop-content-length: 10 Content-length: 10 PROPS-END Revision-number: 2 Prop-content-length: 106 Content-length: 106 K 7 svn:log V 5 hello K 10 svn:author V 7 pmezard K 8 svn:date V 27 2009-06-21T16:34:56.150049Z PROPS-END Node-path: trunk/à Node-kind: dir Node-action: add Prop-content-length: 10 Content-length: 10 PROPS-END Node-path: trunk/à/é Node-kind: file Node-action: add Prop-content-length: 10 Text-content-length: 2 Text-content-md5: e29311f6f1bf1af907f9ef9f44b8328b Text-content-sha1: e983f374794de9c64e3d1c1de1d490c0756eeeff Content-length: 12 PROPS-END d Node-path: trunk/é Node-kind: file Node-action: add Prop-content-length: 10 Text-content-length: 2 Text-content-md5: 9ffbf43126e33be52cd2bf7e01d627f9 Text-content-sha1: 094e3afb2fe8dfe82f63731cdcd3b999f4856cff Content-length: 12 PROPS-END e Revision-number: 3 Prop-content-length: 112 Content-length: 112 K 7 svn:log V 10 copy files K 10 svn:author V 7 pmezard K 8 svn:date V 27 2009-06-21T16:34:59.089402Z PROPS-END Node-path: trunk/è Node-kind: file Node-action: add Node-copyfrom-rev: 2 Node-copyfrom-path: trunk/é Text-copy-source-md5: 9ffbf43126e33be52cd2bf7e01d627f9 Text-copy-source-sha1: 094e3afb2fe8dfe82f63731cdcd3b999f4856cff Node-path: trunk/ù Node-kind: dir Node-action: add Node-copyfrom-rev: 2 Node-copyfrom-path: trunk/à Node-path: trunk/à Node-action: delete Node-path: trunk/é Node-action: delete Revision-number: 4 Prop-content-length: 114 Content-length: 114 K 7 svn:log V 12 remove files K 10 svn:author V 7 pmezard K 8 svn:date V 27 2009-06-21T16:35:00.165121Z PROPS-END Node-path: trunk/è Node-action: delete Node-path: trunk/ù Node-action: delete Revision-number: 5 Prop-content-length: 120 Content-length: 120 K 7 svn:log V 18 branch to branché K 10 svn:author V 7 pmezard K 8 svn:date V 27 2009-06-21T16:35:03.079138Z PROPS-END Node-path: branches/branché Node-kind: dir Node-action: add Node-copyfrom-rev: 4 Node-copyfrom-path: trunk Revision-number: 6 Prop-content-length: 121 Content-length: 121 K 7 svn:log V 19 branch to branchée K 10 svn:author V 7 pmezard K 8 svn:date V 27 2009-06-21T16:35:06.060801Z PROPS-END Node-path: branches/branchée Node-kind: dir Node-action: add Node-copyfrom-rev: 5 Node-copyfrom-path: branches/branché Revision-number: 7 Prop-content-length: 110 Content-length: 110 K 7 svn:log V 9 tag trunk K 10 svn:author V 7 pmezard K 8 svn:date V 27 2009-06-21T16:35:09.061530Z PROPS-END Node-path: tags/branché Node-kind: dir Node-action: add Node-copyfrom-rev: 6 Node-copyfrom-path: trunk Revision-number: 8 Prop-content-length: 114 Content-length: 114 K 7 svn:log V 12 tag branché K 10 svn:author V 7 pmezard K 8 svn:date V 27 2009-06-21T16:35:11.068562Z PROPS-END Node-path: tags/branchée Node-kind: dir Node-action: add Node-copyfrom-rev: 6 Node-copyfrom-path: branches/branchée