On Sun, May 04, 2025 at 01:00:16AM -0700, Junio C Hamano wrote: > $ git show -s | cat > warning: exhaustive rename detection was skipped due to too many files. > warning: you may want to set your diff.renameLimit variable to at least 6123 and retry the command. > commit a3a9dd8be6b8767e690b014715aefa2ba39672e2 (HEAD -> master) > Author: Junio C Hamano <gitster@xxxxxxxxx> > Date: Sat Apr 19 14:27:03 2025 -0700 > > Something something something > > As we have -M (rename detection) on by default these days, and this > particular commit has very many deletions and creations, if we were > asking to show some diff (not necessarily patch text output, but > just "--stat" or even "--raw") it is fair to warn about rename > detection being limited by diff.renameLimit. > > But the command knows that with "-s" the user declined to show any > diff computation, so it feels wrong to even _count_ how many > diff_filepairs there are and comparing with the renameLimit, in > order to warn about busting the limit. This seemed eerily familiar. See this thread: https://lore.kernel.org/git/87h750q1b9.fsf@xxxxxxx/ and in particular this proposal: https://lore.kernel.org/git/YqI%2FTcZyXomxtXtN@xxxxxxxxxxxxxxxxxxxxxxx/ I've been carrying that patch in my tree (reproduced below), but I don't remember why I never polished it. I wonder if it was the question about --exit-code below. Or maybe I was just nervous about other corner cases. -- >8 -- Subject: [PATCH] show: skip diff when possible Running: git show -s $commit will still compute a diff for $commit, even though we aren't going to show it. This is wasted computation, since it cannot affect the output or exit code of the program. In the more general case: - if the requested diff format is NO_OUTPUT, then we won't change the output of the diff itself - if rev_info.always_show_header is set, then we will show the commit regardless of whether the diff is empty (which is true for git-show, for example, but not git-log) - we don't use --exit-code here (should check?) Signed-off-by: Jeff King <peff@xxxxxxxx> --- log-tree.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/log-tree.c b/log-tree.c index a4d4ab59ca..740219ce99 100644 --- a/log-tree.c +++ b/log-tree.c @@ -1105,6 +1105,10 @@ static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log if (!all_need_diff && !opt->merges_need_diff) return 0; + if (opt->diffopt.output_format == DIFF_FORMAT_NO_OUTPUT && + opt->always_show_header) + return 0; + parse_commit_or_die(commit); oid = get_commit_tree_oid(commit); -- 2.49.0.754.gd827f9aa09
