[PATCH] cache-tree: invalidate i-t-a paths after writing trees

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

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), an index with i-t-a entries can
write trees. 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.

The invalidation is done after calling update_one() in
cache_tree_update() for simplicity because it's probably not worth the
complexity of changing a recursive function and the performance
bottleneck won't likely fall to this new loop, rather in
write_sha1_file or hash_sha1_file. But this means that if update_one()
has new call sites, they must re-do the same what this commit does to
avoid the same fault.

Reported-by: Jonathon Mah <me@JonathonMah.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 cache-tree.c          |  3 +++
 t/t2203-add-intent.sh | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/cache-tree.c b/cache-tree.c
index 28ed657..30a8018 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -381,6 +381,9 @@ int cache_tree_update(struct cache_tree *it,
 	i = update_one(it, cache, entries, "", 0, flags);
 	if (i < 0)
 		return i;
+	for (i = 0; i < entries; i++)
+		if (cache[i]->ce_flags & CE_INTENT_TO_ADD)
+			cache_tree_invalidate_path(it, cache[i]->name);
 	return 0;
 }
 
diff --git a/t/t2203-add-intent.sh b/t/t2203-add-intent.sh
index ec35409..2a4a749 100755
--- a/t/t2203-add-intent.sh
+++ b/t/t2203-add-intent.sh
@@ -62,5 +62,25 @@ test_expect_success 'can "commit -a" with an i-t-a entry' '
 	git commit -a -m all
 '
 
+test_expect_success 'cache-tree invalidates i-t-a paths' '
+	git reset --hard &&
+	mkdir dir &&
+	: >dir/foo &&
+	git add dir/foo &&
+	git commit -m foo &&
+
+	: >dir/bar &&
+	git add -N dir/bar &&
+	git diff --cached --name-only >actual &&
+	echo dir/bar >expect &&
+	test_cmp expect actual &&
+
+	git write-tree >/dev/null &&
+
+	git diff --cached --name-only >actual &&
+	echo dir/bar >expect &&
+	test_cmp expect actual
+'
+
 test_done
 
-- 
1.8.0.rc2.23.g1fb49df