From 9ae39fef7f3764537e029b57687f6a0a3163e810 Mon Sep 17 00:00:00 2001 From: Elijah Newren Date: Mon, 17 Jan 2022 18:25:55 +0000 Subject: merge-ort: avoid assuming all renames detected In commit 8b09a900a1 ("merge-ort: restart merge with cached renames to reduce process entry cost", 2021-07-16), we noted that in the merge-ort steps of collect_merge_info() detect_and_process_renames() process_entries() that process_entries() was expensive, and we could often make it cheaper by changing this to collect_merge_info() detect_and_process_renames() collect_merge_info() detect_and_process_renames() process_entries() because the second collect_merge_info() would be cheaper (we could avoid traversing into some directories), the second detect_and_process_renames() would be free since we had already detected all renames, and then process_entries() has far fewer entries to handle. However, this was built on the assumption that the first detect_and_process_renames() actually detected all potential renames. If someone has merge.renameLimit set to some small value, that assumption is violated which manifests later with the following message: $ git -c merge.renameLimit=1 rebase upstream ... git: merge-ort.c:546: clear_or_reinit_internal_opts: Assertion `renames->cached_pairs_valid_side == 0' failed. Turn off this cache-renames-and-restart whenever we cannot detect all renames, and add a testcase that would have caught this problem. Reported-by: Taylor Blau Signed-off-by: Elijah Newren Tested-by: Taylor Blau Signed-off-by: Junio C Hamano --- t/t6429-merge-sequence-rename-caching.sh | 67 ++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) (limited to 't') diff --git a/t/t6429-merge-sequence-rename-caching.sh b/t/t6429-merge-sequence-rename-caching.sh index 035edc40b1..f2bc8a7d2a 100755 --- a/t/t6429-merge-sequence-rename-caching.sh +++ b/t/t6429-merge-sequence-rename-caching.sh @@ -697,4 +697,71 @@ test_expect_success 'caching renames only on upstream side, part 2' ' ) ' +# +# The following testcase just creates two simple renames (slightly modified +# on both sides but without conflicting changes), and a directory full of +# files that are otherwise uninteresting. The setup is as follows: +# +# base: unrelated/ +# numbers +# values +# upstream: modify: numbers +# modify: values +# topic: add: unrelated/foo +# modify: numbers +# modify: values +# rename: numbers -> sequence +# rename: values -> progression +# +# This is a trivial rename case, but we're curious what happens with a very +# low renameLimit interacting with the restart optimization trying to notice +# that unrelated/ looks like a trivial merge candidate. +# +test_expect_success 'avoid assuming we detected renames' ' + git init redo-weirdness && + ( + cd redo-weirdness && + + mkdir unrelated && + for i in $(test_seq 1 10) + do + >unrelated/$i + done && + test_seq 2 10 >numbers && + test_seq 12 20 >values && + git add numbers values unrelated/ && + git commit -m orig && + + git branch upstream && + git branch topic && + + git switch upstream && + test_seq 1 10 >numbers && + test_seq 11 20 >values && + git add numbers && + git commit -m "Some tweaks" && + + git switch topic && + + >unrelated/foo && + test_seq 2 12 >numbers && + test_seq 12 22 >values && + git add numbers values unrelated/ && + git mv numbers sequence && + git mv values progression && + git commit -m A && + + # + # Actual testing + # + + git switch --detach topic^0 && + + test_must_fail git -c merge.renameLimit=1 rebase upstream && + + git ls-files -u >actual && + ! test_file_is_empty actual + ) +' + test_done -- cgit v1.2.3