This patch series adds a new diff option that enables ignoring changes
whose all lines (changed, removed, and added) match a given regular
expression. This is similar to the -I option in standalone diff
utilities and can be used e.g. to look for unrelated changes in commits
containing a large number of automatically applied modifications (e.g. a
tree-wide string replacement). The difference between -G/-S and the new
-I option is that the latter filters output on a per-change basis.
I personally found this feature handy quite a few times while reviewing
patches and a quick web search yields some questions from other people
looking for something like this, so I thought I would take a shot at
submitting it upstream.
Please note that while this patch series in its current shape builds,
seems to pass tests, and appears to work as I would expect it to, this
is my first attempt at contributing to Git and I did come across a few
stumbling blocks:
- Instead of adding an extra flag for 'xdl_opts', would it be better
to make sure xpparam_t structures are always zero-initialized before
xdl_diff() is called (see commit message for patch 1 for context)?
- If this patch series is accepted, should xdl_mark_ignorable() be
renamed to something like xdl_mark_ignorable_blank() for slightly
improved code clarity?
- Would a more thorough explanation of the option help or hurt?
- Given that hunk emitting rules are the same for the -I option
proposed in this patch series as for --ignore-blank-lines, is it
necessary to duplicate the (impressively extensive!)
--inter-hunk-context tests in t/t4015-diff-whitespace.sh for -I? I
decided against doing that for the time being (though I did add some
basic tests for such scenarios in patch 2, see the "with -U1" test).
- Should tests be added in a separate commit? This is what I did as I
thought it would help with readability, but...
Thanks in advance for taking a look!
Michał Kępień (2):
diff: add -I<regex> that ignores matching changes
t: add -I<regex> tests
Documentation/diff-options.txt | 3 +
diff.c | 16 ++
diff.h | 2 +
t/t4069-diff-ignore-regex.sh | 330 +++++++++++++++++++++++++++++++++
xdiff/xdiff.h | 2 +
xdiff/xdiffi.c | 36 ++++
6 files changed, 389 insertions(+)
create mode 100755 t/t4069-diff-ignore-regex.sh
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2.28.0
