view mercurial/helptext/diffs.txt @ 45203:ae5c1a3bc339

commitctx: extract the function in a dedicated module

the function have few callers (< 15) is quite long a mostly independent from the
repository itself. It seems like a good candidate to reduce the bloatness of the
localrepository class. Extracting it will help us cleaning the code up and
splitting it into more reasonable-size function.

We don't use a copy trick because the amount of code extract is quite small
(<5%) and the de-indent means every single line change anyway. So this is not
deemed valuable to do so.

This is part of a larger refactoring/cleanup of the commitctx code to clarify
and augment the logic gathering metadata useful for copy tracing. The current
code is a tad too long and entangled to make such update easy.

Differential Revision: https://phab.mercurial-scm.org/D8709

Mercurial's default format for showing changes between two versions of
a file is compatible with the unified format of GNU diff, which can be
used by GNU patch and many other standard tools.

While this standard format is often enough, it does not encode the
following information:

- executable status and other permission bits
- copy or rename information
- changes in binary files
- creation or deletion of empty files

Mercurial also supports the extended diff format from the git VCS
which addresses these limitations. The git diff format is not produced
by default because a few widespread tools still do not understand this
format.

This means that when generating diffs from a Mercurial repository
(e.g. with :hg:`export`), you should be careful about things like file
copies and renames or other things mentioned above, because when
applying a standard diff to a different repository, this extra
information is lost. Mercurial's internal operations (like push and
pull) are not affected by this, because they use an internal binary
format for communicating changes.

To make Mercurial produce the git extended diff format, use the --git
option available for many commands, or set 'git = True' in the [diff]
section of your configuration file. You do not need to set this option
when importing diffs in this format or using them in the mq extension.