mercurial/help/diffs.txt
author Adrian Buehlmann <adrian@cadifra.com>
Mon, 14 Feb 2011 11:12:22 +0100
changeset 13374 1c613c1ae43d
parent 12083 ebfc46929f3e
permissions -rw-r--r--
win32: optimize parameters for the CreateFile call in _getfileinfo Set dwDesiredAccess to 0 instead of GENERIC_READ. Zero is enough for querying the file metadata. We don't even need to access the -contents- of the file. Set dwShareMode to FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE instead of the overly restrictive FILE_SHARE_READ. There is no need to cause write or delete accesses by other processes to fail while we are querying file metadata. See http://msdn.microsoft.com/en-us/library/aa363858(v=vs.85).aspx

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.