[PATCH v2 13/20] unpack-trees: allow sparse directories

From: Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
Date: Mar 10, 2021, 19:30 UTC
Message-ID: <6f1ebe6ccc08d10715ee339fe04289db341dfdc4.1615404665.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.883.v2.git.1615404664.gitgitgadget@gmail.com>

From: Derrick Stolee <dstolee@microsoft.com>

The index_pos_by_traverse_info() currently throws a BUG() when a directory entry exists exactly in the index. We need to consider that it is possible to have a directory in a sparse index as long as that entry is itself marked with the skip-worktree bit.

The 'pos' variable is assigned a negative value if an exact match is not found. Since a directory name can be an exact match, it is no longer an error to have a nonnegative 'pos' value.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 unpack-trees.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/unpack-trees.c b/unpack-trees.c
index 4dd99219073a..b324eec2a5d1 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -746,9 +746,12 @@ static int index_pos_by_traverse_info(struct name_entry *names,
 	strbuf_make_traverse_path(&name, info, names->path, names->pathlen);
 	strbuf_addch(&name, '/');
 	pos = index_name_pos(o->src_index, name.buf, name.len);
-	if (pos >= 0)
-		BUG("This is a directory and should not exist in index");
-	pos = -pos - 1;
+	if (pos >= 0) {
+		if (!o->src_index->sparse_index ||
+		    !(o->src_index->cache[pos]->ce_flags & CE_SKIP_WORKTREE))
+			BUG("This is a directory and should not exist in index");
+	} else
+		pos = -pos - 1;
 	if (pos >= o->src_index->cache_nr ||
 	    !starts_with(o->src_index->cache[pos]->name, name.buf) ||
 	    (pos > 0 && starts_with(o->src_index->cache[pos-1]->name, name.buf)))

-- 
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