Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx> writes:
> Intent-to-add entries used to forbid writing trees so it was not a
> problem. After commit 3f6d56d (commit: ignore intent-to-add entries
> instead of refusing - 2012-02-07), we can generate trees from an index
> with i-t-a entries.
>
> However, the commit forgets to invalidate all paths leading to i-t-a
> entries. With fully valid cache-tree (e.g. after commit or
> write-tree), diff operations may prefer cache-tree to index and not
> see i-t-a entries in the index, because cache-tree does not have them.
>
> Reported-by: Jonathon Mah <me@xxxxxxxxxxxxxxx>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
> ---
> This version ensures that entry_count can only be >= -1 after
> update_one returns. Not ideal but good enough.
>
> cache-tree.c | 40 ++++++++++++++++++++++++++++++++++++----
> t/t2203-add-intent.sh | 20 ++++++++++++++++++++
> 2 files changed, 56 insertions(+), 4 deletions(-)
>
> diff --git a/cache-tree.c b/cache-tree.c
> index 28ed657..1fbc81a 100644
> --- a/cache-tree.c
> +++ b/cache-tree.c
> @@ -248,6 +248,7 @@ static int update_one(struct cache_tree *it,
> int missing_ok = flags & WRITE_TREE_MISSING_OK;
> int dryrun = flags & WRITE_TREE_DRY_RUN;
> int i;
> + int to_invalidate = 0;
>
> if (0 <= it->entry_count && has_sha1_file(it->sha1))
> return it->entry_count;
> @@ -324,7 +325,14 @@ static int update_one(struct cache_tree *it,
> if (!sub)
> die("cache-tree.c: '%.*s' in '%s' not found",
> entlen, path + baselen, path);
> - i += sub->cache_tree->entry_count - 1;
> + i--; /* this entry is already counted in "sub" */
Huh?
The "-1" in the original is the bog-standard compensation for the
for(;;i++) loop.
> + if (sub->cache_tree->entry_count < 0) {
> + i -= sub->cache_tree->entry_count;
> + sub->cache_tree->entry_count = -1;
> + to_invalidate = 1;
> + }
> + else
> + i += sub->cache_tree->entry_count;
While the rewritten version is not *wrong* per-se, I have a feeling
that it may be much easier to read if written like this:
if (sub->cache_tree_entry_count < 0) {
to_invalidate = 1;
to_skip = 0 - sub->cache_tree_entry_count;
sub->cache_tree_entry_count = -1;
} else {
to_skip = sub->cache_tree_entry_count;
}
i += to_skip - 1;
> @@ -360,7 +383,7 @@ static int update_one(struct cache_tree *it,
> }
>
> strbuf_release(&buffer);
> - it->entry_count = i;
> + it->entry_count = to_invalidate ? -i : i;
> #if DEBUG
> fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
> it->entry_count, it->subtree_nr,
> @@ -381,6 +404,15 @@ int cache_tree_update(struct cache_tree *it,
> i = update_one(it, cache, entries, "", 0, flags);
> if (i < 0)
> return i;
> + /*
> + * update_one() uses negative entry_count as a way to mark an
> + * entry invalid _and_ pass the number of entries back to
> + * itself at the parent level. This is for internal use and
> + * should not be leaked out after the top-level update_one
> + * exits.
> + */
> + if (it->entry_count < 0)
> + it->entry_count = -1;
Nice. I think what entry_count means immediately after update_one()
returned should be commented near the beginning of that function,
too, though.
Thanks.
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