From 816147e7bab0c7e9c3a578ce166c55d5f7a64a8a Mon Sep 17 00:00:00 2001 From: Elijah Newren Date: Sat, 20 Mar 2021 00:03:53 +0000 Subject: merge-recursive: add a bunch of FIXME comments documenting known bugs The plan is to just delete merge-recursive, but not until everyone is comfortable with merge-ort as a replacement. Given that I haven't switched all callers of merge-recursive over yet (e.g. git-am still uses merge-recursive), maybe there's some value documenting known bugs in the algorithm in case we end up keeping it or someone wants to dig it up in the future. Signed-off-by: Elijah Newren Reviewed-by: Derrick Stolee Signed-off-by: Junio C Hamano --- merge-recursive.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) (limited to 'merge-recursive.c') diff --git a/merge-recursive.c b/merge-recursive.c index b052974f19..99a197597d 100644 --- a/merge-recursive.c +++ b/merge-recursive.c @@ -1075,6 +1075,11 @@ static int merge_3way(struct merge_options *opt, read_mmblob(&src1, &a->oid); read_mmblob(&src2, &b->oid); + /* + * FIXME: Using a->path for normalization rules in ll_merge could be + * wrong if we renamed from a->path to b->path. We should use the + * target path for where the file will be written. + */ merge_status = ll_merge(result_buf, a->path, &orig, base, &src1, name1, &src2, name2, opt->repo->index, &ll_opts); @@ -1154,6 +1159,8 @@ static void print_commit(struct commit *commit) struct strbuf sb = STRBUF_INIT; struct pretty_print_context ctx = {0}; ctx.date_mode.type = DATE_NORMAL; + /* FIXME: Merge this with output_commit_title() */ + assert(!merge_remote_util(commit)); format_commit_message(commit, " %h: %m %s", &sb, &ctx); fprintf(stderr, "%s\n", sb.buf); strbuf_release(&sb); @@ -1177,6 +1184,11 @@ static int merge_submodule(struct merge_options *opt, int search = !opt->priv->call_depth; /* store a in result in case we fail */ + /* FIXME: This is the WRONG resolution for the recursive case when + * we need to be careful to avoid accidentally matching either side. + * Should probably use o instead there, much like we do for merging + * binaries. + */ oidcpy(result, a); /* we can not handle deletion conflicts */ @@ -1301,6 +1313,13 @@ static int merge_mode_and_contents(struct merge_options *opt, if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) { result->clean = 0; + /* + * FIXME: This is a bad resolution for recursive case; for + * the recursive case we want something that is unlikely to + * accidentally match either side. Also, while it makes + * sense to prefer regular files over symlinks, it doesn't + * make sense to prefer regular files over submodules. + */ if (S_ISREG(a->mode)) { result->blob.mode = a->mode; oidcpy(&result->blob.oid, &a->oid); @@ -1349,6 +1368,7 @@ static int merge_mode_and_contents(struct merge_options *opt, free(result_buf.ptr); if (ret) return ret; + /* FIXME: bug, what if modes didn't match? */ result->clean = (merge_status == 0); } else if (S_ISGITLINK(a->mode)) { result->clean = merge_submodule(opt, &result->blob.oid, @@ -2664,6 +2684,14 @@ static int process_renames(struct merge_options *opt, struct string_list b_by_dst = STRING_LIST_INIT_NODUP; const struct rename *sre; + /* + * FIXME: As string-list.h notes, it's O(n^2) to build a sorted + * string_list one-by-one, but O(n log n) to build it unsorted and + * then sort it. Note that as we build the list, we do not need to + * check if the existing destination path is already in the list, + * because the structure of diffcore_rename guarantees we won't + * have duplicates. + */ for (i = 0; i < a_renames->nr; i++) { sre = a_renames->items[i].util; string_list_insert(&a_by_dst, sre->pair->two->path)->util @@ -3602,6 +3630,15 @@ static int merge_recursive_internal(struct merge_options *opt, return err(opt, _("merge returned no commit")); } + /* + * FIXME: Since merge_recursive_internal() is only ever called by + * places that ensure the index is loaded first + * (e.g. builtin/merge.c, rebase/sequencer, etc.), in the common + * case where the merge base was unique that means when we get here + * we immediately discard the index and re-read it, which is a + * complete waste of time. We should only be discarding and + * re-reading if we were forced to recurse. + */ discard_index(opt->repo->index); if (!opt->priv->call_depth) repo_read_index(opt->repo); -- cgit v1.2.3