Diff Formats

    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

    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

    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.