[v5,7/9] attr: be careful about sparse directories

Commit Message

Derrick Stolee Sept. 8, 2021, 1:42 a.m. UTC

From: Derrick Stolee <[e-mail]>

Signed-off-by: Derrick Stolee <[e-mail]>
---
 attr.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

Patch

diff --git a/attr.c b/attr.c
index d029e681f28..79adaa50ea1 100644
--- a/attr.c
+++ b/attr.c
@@ -14,6 +14,7 @@ 
 #include "utf8.h"
 #include "quote.h"
 #include "thread-utils.h"
+#include "dir.h"
 
 const char git_attr__true[] = "(builtin)true";
 const char git_attr__false[] = "\0(builtin)false";
@@ -744,6 +745,20 @@  static struct attr_stack *read_attr_from_index(struct index_state *istate,
 	if (!istate)
 		return NULL;
 
+	/*
+	 * The .gitattributes file only applies to files within its
+	 * parent directory. In the case of cone-mode sparse-checkout,
+	 * the .gitattributes file is sparse if and only if all paths
+	 * within that directory are also sparse. Thus, don't load the
+	 * .gitattributes file since it will not matter.
+	 *
+	 * In the case of a sparse index, it is critical that we don't go
+	 * looking for a .gitattributes file, as doing so would cause the
+	 * index to expand.
+	 */
+	if (!path_in_cone_mode_sparse_checkout(path, istate))
+		return NULL;
+
 	buf = read_blob_data_from_index(istate, path, NULL);
 	if (!buf)
 		return NULL;