218 

   219     (['gitdiffs'], _('Using git Diffs'),

   220      _(r'''

   221     In several places, Mercurial supports two separate variations on

   222     the unified diff format: normal diffs, as are de facto standardized

   223     by GNU's patch utility, and git diffs, invented for the git VCS.

   224 

   225     The git diff format is an addition of some information to the normal

   226     diff format, which allows diff to convey changes in file permissions

   227     as well as the creation, deletion, renaming and copying of files, as

   228     well as diffs for binary files (unsupported by standard diff),

   229     operations which are very useful to modern version control systems

   230     such as Mercurial, in trying to faithfully replay your changes.

   231 

   232     In building Mercurial, we made a choice to support the git diff

   233     format, but we haven't made it the default. This is because for a

   234     long time, the format for unified diffs we usually use has been 

   235     defined by GNU patch, and it doesn't (yet) support git's extensions

   236     to the diff format. This means that, when extracting diffs from a

   237     Mercurial repository (through the diff command, for example), you

   238     must be careful about things like file copies and renames (file

   239     creation and deletion are mostly handled fine by the traditional

   240     diff format, with some rare edge cases for which the git extensions

   241     can be used). Mercurial's internal operations (like push and pull)

   242     are not affected by these differences, because they use a different,

   243     binary format for communicating changes.

   244 

   245     To use git diffs, use the --git option for relevant commands, or

   246     enable them in a hgrc, setting 'git = True' in the [diff] section.

   247     ''')),