[PATCH] 2.36 gitk/diff-tree --stdin regression fix
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Apr 26, 2022, 16:11 UTC
- Message-ID
- <xmqq7d7bsu2n.fsf@gitster.g>
- In-Reply-To
- <xmqqo80nsw5h.fsf@gitster.g>
This only surfaced as a regression after 2.36 release, but the breakage was already there with us for at least a year.
The diff_free() call is to be used after we completely finished with a diffopt structure. After "git diff A B" finishes producing output, calling it before process exit is fine. But there are commands that prepares diff_options struct once, compares two sets of paths, releases resources that were used to do the comparison, then reuses the same diff_option struct to go on to compare the next two sets of paths, like "git log -p".
After "git log -p" finishes showing a single commit, calling it before it goes on to the next commit is NOT fine. There is a mechanism, the .no_free member in diff_options struct, to help "git log" to avoid calling diff_free() after showing each commit and instead call it just one. When the mechanism was introduced in e900d494 (diff: add an API for deferred freeing, 2021-02-11), however, we forgot to do the same to "diff-tree --stdin", which *is* a moral equivalent to "git log".
During 2.36 release cycle, we started clearing the pathspec in diff_free(), so programs like gitk that runs
git diff-tree --stdin -- <pathspec>
downstream of a pipe, processing one commit after another, started showing irrelevant comparison outside the given <pathspec> from the second commit. The same commit, by forgetting to teach the .no_free mechanism, broke "diff-tree --stdin -I<regexp>" and nobody noticed it for over a year, presumably because it is so seldom used an option.
But <pathspec> is a different story. The breakage was very prominently visible and was reported immediately after 2.36 was released.
Fix this breakage by mimicking how "git log" utilizes the .no_free member so that "diff-tree --stdin" behaves more similarly to "log".
Protect the fix with a few new tests.
Reported-by: Matthias Aßhauer <mha1993@live.de> Helped-by: René Scharfe <l.s.r@web.de> Helped-by: Phillip Wood <phillip.wood123@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> ---
* I feel MUCH better with this than the revert, now Phillip helped me to get the root cause straight. Addition of clear_pathspec() to diff_tree() was *not* a mistake but is quite reasonable thing to do. Not using the .no_free hack in a code path that needed it was.
builtin/diff-tree.c | 3 +++ log-tree.c | 1 + t/t4013-diff-various.sh | 14 ++++++++++++++ 3 files changed, 18 insertions(+)
diff --git a/builtin/diff-tree.c b/builtin/diff-tree.c index 0e0ac1f167..116097a404 100644 --- a/builtin/diff-tree.c +++ b/builtin/diff-tree.c @@ -195,6 +195,7 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix) int saved_dcctc = 0; opt->diffopt.rotate_to_strict = 0; + opt->diffopt.no_free = 1; if (opt->diffopt.detect_rename) { if (!the_index.cache) repo_read_index(the_repository); @@ -217,6 +218,8 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix) } opt->diffopt.degraded_cc_to_c = saved_dcctc; opt->diffopt.needed_rename_limit = saved_nrl; + opt->diffopt.no_free = 0; + diff_free(&opt->diffopt); } return diff_result_code(&opt->diffopt, 0); diff --git a/log-tree.c b/log-tree.c index 25165e2a91..f8c18fd8b9 100644 --- a/log-tree.c +++ b/log-tree.c @@ -1098,6 +1098,7 @@ int log_tree_commit(struct rev_info *opt, struct commit *commit) opt->loginfo = &log; opt->diffopt.no_free = 1; + /* NEEDSWORK: no restoring of no_free? Why? */ if (opt->line_level_traverse) return line_log_print(opt, commit); diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh index 750aee17ea..628b01f355 100755 --- a/t/t4013-diff-various.sh +++ b/t/t4013-diff-various.sh @@ -542,6 +542,20 @@ test_expect_success 'diff-tree --stdin with log formatting' ' test_cmp expect actual ' +test_expect_success 'diff-tree --stdin with pathspec' ' + cat >expect <<-EOF && + Third + + dir/sub + Second + + dir/sub + EOF + git rev-list master^ | + git diff-tree -r --stdin --name-only --format=%s dir >actual && + test_cmp expect actual +' + test_expect_success 'diff -I<regex>: setup' ' git checkout master && test_seq 50 >file0 &&
-- 2.36.0-202-g319c44b8f9