Make --no-ext-diff disable diff.<driver>.process in addition to
diff.<driver>.command. Although the two mechanisms work differently
(command replaces Git's output, process feeds hunks back into the
pipeline), both invoke external tools and --no-ext-diff means
"no external tools."
Replace the OPT_BOOL for --ext-diff with an OPT_CALLBACK that
sets both allow_external and no_diff_process, so a single option
controls both. Passing --ext-diff explicitly clears
no_diff_process, so a later --ext-diff overrides an earlier
--no-ext-diff.
Disable the diff process unconditionally in format-patch so that
generated patches are always based on the builtin diff algorithm
and can be applied reliably by recipients who do not have the
external tool.
Document that --diff-algorithm also bypasses the diff process,
since it sets ignore_driver_algorithm which diff_process_fill_hunks
already checks.
Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The diff algorithm used in 'git-blame(1)' is set to 'myers',
without the possibility to change it aside from the `--minimal` option.
There has been long-standing interest in changing the default diff
algorithm to "histogram", and Git 3.0 was floated as a possible occasion
for taking some steps towards that:
https://lore.kernel.org/git/xmqqed873vgn.fsf@gitster.g/
As a preparation for this move, it is worth making sure that the diff
algorithm is configurable where useful.
Make it configurable in the `git-blame(1)` command by introducing the
`--diff-algorithm` option and make honor the `diff.algorithm` config
variable. Keep Myers diff as the default.
Signed-off-by: Antonin Delpeuch <antonin@delpeuch.eu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
