Mercurial > hg
view mercurial/help/diffs.txt @ 37007:143219fc2620
debugcommands: introduce actions to perform deterministic reads
"readavailable" is useful as a debugging device to see what data is
available on a pipe. But the mechanism isn't deterministic because
what's available on a pipe is highly conditional on timing, system
load, OS behavior, etc. This makes it not suitable for tests.
We introduce "ereadline," "read," and "eread" for performing
deterministic I/O operations (at least on blocking file descriptors).
We stop short of converting existing consumers of "readavailable"
in tests because we're working out race conditions and deadlocks
on Windows. But the goal is to eventually move tests away from
"readavailable" to these new APIs.
Differential Revision: https://phab.mercurial-scm.org/D2720
author | Gregory Szorc <gregory.szorc@gmail.com> |
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date | Mon, 12 Mar 2018 15:49:02 -0700 |
parents | ebfc46929f3e |
children |
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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.