From db757e8b8d5527c195c461a04ec35d141ddea48e Mon Sep 17 00:00:00 2001 From: Elijah Newren Date: Wed, 2 Feb 2022 02:37:28 +0000 Subject: show, log: provide a --remerge-diff capability When this option is specified, we remerge all (two parent) merge commits and diff the actual merge commit to the automatically created version, in order to show how users removed conflict markers, resolved the different conflict versions, and potentially added new changes outside of conflict regions in order to resolve semantic merge problems (or, possibly, just to hide other random changes). This capability works by creating a temporary object directory and marking it as the primary object store. This makes it so that any blobs or trees created during the automatic merge are easily removable afterwards by just deleting all objects from the temporary object directory. There are a few ways that this implementation is suboptimal: * `log --remerge-diff` becomes slow, because the temporary object directory can fill with many loose objects while running * the log output can be muddied with misplaced "warning: cannot merge binary files" messages, since ll-merge.c unconditionally writes those messages to stderr while running instead of allowing callers to manage them. * important conflict and warning messages are simply dropped; thus for conflicts like modify/delete or rename/rename or file/directory which are not representable with content conflict markers, there may be no way for a user of --remerge-diff to know that there had been a conflict which was resolved (and which possibly motivated other changes in the merge commit). * when fixing the previous issue, note that some unimportant conflict and warning messages might start being included. We should instead make sure these remain dropped. Subsequent commits will address these issues. Signed-off-by: Elijah Newren Signed-off-by: Junio C Hamano --- diff-merges.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'diff-merges.c') diff --git a/diff-merges.c b/diff-merges.c index 5060ccd890..0af4b3f919 100644 --- a/diff-merges.c +++ b/diff-merges.c @@ -17,6 +17,7 @@ static void suppress(struct rev_info *revs) revs->combined_all_paths = 0; revs->merges_imply_patch = 0; revs->merges_need_diff = 0; + revs->remerge_diff = 0; } static void set_separate(struct rev_info *revs) @@ -45,6 +46,12 @@ static void set_dense_combined(struct rev_info *revs) revs->dense_combined_merges = 1; } +static void set_remerge_diff(struct rev_info *revs) +{ + suppress(revs); + revs->remerge_diff = 1; +} + static diff_merges_setup_func_t func_by_opt(const char *optarg) { if (!strcmp(optarg, "off") || !strcmp(optarg, "none")) @@ -57,6 +64,8 @@ static diff_merges_setup_func_t func_by_opt(const char *optarg) return set_combined; else if (!strcmp(optarg, "cc") || !strcmp(optarg, "dense-combined")) return set_dense_combined; + else if (!strcmp(optarg, "r") || !strcmp(optarg, "remerge")) + return set_remerge_diff; else if (!strcmp(optarg, "m") || !strcmp(optarg, "on")) return set_to_default; return NULL; @@ -110,6 +119,9 @@ int diff_merges_parse_opts(struct rev_info *revs, const char **argv) } else if (!strcmp(arg, "--cc")) { set_dense_combined(revs); revs->merges_imply_patch = 1; + } else if (!strcmp(arg, "--remerge-diff")) { + set_remerge_diff(revs); + revs->merges_imply_patch = 1; } else if (!strcmp(arg, "--no-diff-merges")) { suppress(revs); } else if (!strcmp(arg, "--combined-all-paths")) { -- cgit v1.3 From 0dec322d31db3920872f43bdd2a7ddd282a5be67 Mon Sep 17 00:00:00 2001 From: Elijah Newren Date: Wed, 2 Feb 2022 02:37:37 +0000 Subject: diff-merges: avoid history simplifications when diffing merges Doing diffs for merges are special; they should typically avoid history simplification. For example, with git log --diff-merges=first-parent -- path the default history simplification would remove merge commits from consideration if the file "path" matched the second parent. That is counter to what the user wants when looking for first-parent diffs. Similar comments can be made for --diff-merges=separate (which diffs against both parents) and --diff-merges=remerge (which diffs against a remerge of the merge commit). However, history simplification still makes sense if not doing diffing merges, and it also makes sense for the combined and dense-combined forms of diffing merges (because both of those are defined to only show a diff when the merge result at the relevant paths differs from *both* parents). So, for separate, first-parent, and remerge styles of diff-merges, turn off history simplification. Signed-off-by: Elijah Newren Signed-off-by: Junio C Hamano --- diff-merges.c | 2 ++ t/t4069-remerge-diff.sh | 58 ++++++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 59 insertions(+), 1 deletion(-) (limited to 'diff-merges.c') diff --git a/diff-merges.c b/diff-merges.c index 0af4b3f919..a833fd747a 100644 --- a/diff-merges.c +++ b/diff-merges.c @@ -24,6 +24,7 @@ static void set_separate(struct rev_info *revs) { suppress(revs); revs->separate_merges = 1; + revs->simplify_history = 0; } static void set_first_parent(struct rev_info *revs) @@ -50,6 +51,7 @@ static void set_remerge_diff(struct rev_info *revs) { suppress(revs); revs->remerge_diff = 1; + revs->simplify_history = 0; } static diff_merges_setup_func_t func_by_opt(const char *optarg) diff --git a/t/t4069-remerge-diff.sh b/t/t4069-remerge-diff.sh index fd6bce6478..35f94957fc 100755 --- a/t/t4069-remerge-diff.sh +++ b/t/t4069-remerge-diff.sh @@ -227,7 +227,63 @@ test_expect_success 'remerge-diff w/ pathspec: limits to relevant file including # with sha256 sed -e "s/[0-9a-f]\{7,\}/HASH/g" tmp >expect && - git show --oneline --remerge-diff --full-history resolution -- "letters*" >tmp && + git show --oneline --remerge-diff resolution -- "letters*" >tmp && + sed -e "s/[0-9a-f]\{7,\}/HASH/g" tmp >actual && + test_cmp expect actual +' + +test_expect_success 'setup non-content conflicts' ' + git switch --orphan newbase && + + test_write_lines 1 2 3 4 5 6 7 8 9 >numbers && + git add numbers && + git commit -m base && + + git branch newside1 && + git branch newside2 && + + git checkout newside1 && + test_write_lines 1 2 three 4 5 6 7 8 9 >numbers && + git add numbers && + git commit -m side1 && + + git checkout newside2 && + test_write_lines 1 2 drei 4 5 6 7 8 9 >numbers && + git add numbers && + git commit -m side2 && + + git checkout -b newresolution newside1 && + test_must_fail git merge newside2 && + git checkout --theirs numbers && + git add -u numbers && + git commit -m resolved +' + +test_expect_success 'remerge-diff turns off history simplification' ' + git log -1 --oneline newresolution >tmp && + cat <<-EOF >>tmp && + diff --git a/numbers b/numbers + remerge CONFLICT (content): Merge conflict in numbers + index 070e9e7..5335e78 100644 + --- a/numbers + +++ b/numbers + @@ -1,10 +1,6 @@ + 1 + 2 + -<<<<<<< 96f1e45 (side1) + -three + -======= + drei + ->>>>>>> 4fd522f (side2) + 4 + 5 + 6 + EOF + # We still have some sha1 hashes above; rip them out so test works + # with sha256 + sed -e "s/[0-9a-f]\{7,\}/HASH/g" tmp >expect && + + git show --oneline --remerge-diff newresolution -- numbers >tmp && sed -e "s/[0-9a-f]\{7,\}/HASH/g" tmp >actual && test_cmp expect actual ' -- cgit v1.3