path: root/builtin/diff.c
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authorElijah Newren <>2020-06-11 06:59:33 (GMT)
committerJunio C Hamano <>2020-06-13 00:27:16 (GMT)
commit7233f17577c63c95da0b4a23eefc26125e4971d1 (patch)
treef3723f824db3635569153b63112797eec06b9834 /builtin/diff.c
parentf7f5c6c0baf6b6219b38e69d8623b95cc3cdd3d3 (diff)
clean: optimize and document cases where we recurse into subdirectories
Commit 6b1db43109 ("clean: teach clean -d to preserve ignored paths", 2017-05-23) added the following code block (among others) to git-clean: if (remove_directories) dir.flags |= DIR_SHOW_IGNORED_TOO | DIR_KEEP_UNTRACKED_CONTENTS; The reason for these flags is well documented in the commit message, but isn't obvious just from looking at the code. Add some explanations to the code to make it clearer. Further, it appears git-2.26 did not correctly handle this combination of flags from git-clean. With both these flags and without DIR_SHOW_IGNORED_TOO_MODE_MATCHING set, git is supposed to recurse into all untracked AND ignored directories. git-2.26.0 clearly was not doing that. I don't know the full reasons for that or whether git < 2.27.0 had additional unknown bugs because of that misbehavior, because I don't feel it's worth digging into. As per the huge changes and craziness documented in commit 8d92fb2927 ("dir: replace exponential algorithm with a linear one", 2020-04-01), the old algorithm was a mess and was thrown out. What I can say is that git-2.27.0 correctly recurses into untracked AND ignored directories with that combination. However, in clean's case we don't need to recurse into ignored directories; that is just a waste of time. Thus, when git-2.27.0 started correctly handling those flags, we got a performance regression report. Rather than relying on other bugs in fill_directory()'s former logic to provide the behavior of skipping ignored directories, make use of the DIR_SHOW_IGNORED_TOO_MODE_MATCHING value specifically added in commit eec0f7f2b7 ("status: add option to show ignored files differently", 2017-10-30) for this purpose. Reported-by: Brian Malehorn <> Signed-off-by: Elijah Newren <> Signed-off-by: Junio C Hamano <>
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