[v6,09/14] dir.c: accept a directory as part of cone-mode patterns

Commit Message

Derrick Stolee June 29, 2021, 1:51 a.m. UTC

From: Derrick Stolee <[e-mail]>

When we have sparse directory entries in the index, we want to compare
that directory against sparse-checkout patterns. Those pattern matching
algorithms are built expecting a file path, not a directory path. This
is especially important in the "cone mode" patterns which will match
files that exist within the "parent directories" as well as the
recursive directory matches.

If path_matches_pattern_list() is given a directory, we can add a fake
filename ("-") to the directory and get the same results as before,
assuming we are in cone mode. Since sparse index requires cone mode
patterns, this is an acceptable assumption.

Signed-off-by: Derrick Stolee <[e-mail]>
---
 dir.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

Patch

diff --git a/dir.c b/dir.c
index ebe5ec046e0..2155107b1d7 100644
--- a/dir.c
+++ b/dir.c
@@ -1397,6 +1397,17 @@  enum pattern_match_result path_matches_pattern_list(
 	strbuf_addch(&parent_pathname, '/');
 	strbuf_add(&parent_pathname, pathname, pathlen);
 
+	/*
+	 * Directory entries are matched if and only if a file
+	 * contained immediately within them is matched. For the
+	 * case of a directory entry, modify the path to create
+	 * a fake filename within this directory, allowing us to
+	 * use the file-base matching logic in an equivalent way.
+	 */
+	if (parent_pathname.len > 0 &&
+	    parent_pathname.buf[parent_pathname.len - 1] == '/')
+		strbuf_add(&parent_pathname, "-", 1);
+
 	if (hashmap_contains_path(&pl->recursive_hashmap,
 				  &parent_pathname)) {
 		result = MATCHED_RECURSIVE;