view mercurial/helptext/diffs.txt @ 45377:da3b7c80aa34

hgweb: handle None from templatedir() equally bad in webcommands.py

The following paragraph is based just on my reading of the code; I
have not tried to test it.

Before my recent work on templates in frozen binaries, it seems both
`hgwebdir_mod.py` and `webcommands.py` would pass in an empty list
into `staticfile()` when running in a frozen binary. That would then
result in a variable in that function (`path`) not getting bound
before its first use. I then changed that without thinking in D8786 so
we passed a `None` value into the function, which made it break in
another way (trying to iterate over `None`). Then I tried to fix it up
in D8810, but I only changed `hgwebdir_mod.py` for some reason, and it
still doesn't actually work in frozen binaries (which seems fair,
since was broken before my changes too).

This patch just replicates the half-assed "fix" from D8810 in
`webcommands.py`, so they look more similar so I can start refactoring
them in the same way.

Differential Revision: https://phab.mercurial-scm.org/D8933

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.