1 files changed, 68 insertions, 29 deletions
diff --git a/attr.c b/attr.c
index d45d34058d..e62876dfd3 100644
--- a/attr.c
+++ b/attr.c
@@ -6,23 +6,26 @@
  * an insanely large number of attributes.
  */
 
-#include "cache.h"
-#include "alloc.h"
+#include "git-compat-util.h"
 #include "config.h"
 #include "environment.h"
 #include "exec-cmd.h"
 #include "attr.h"
 #include "dir.h"
 #include "gettext.h"
+#include "path.h"
 #include "utf8.h"
 #include "quote.h"
+#include "read-cache-ll.h"
 #include "revision.h"
-#include "object-store.h"
+#include "object-store-ll.h"
 #include "setup.h"
 #include "thread-utils.h"
 #include "tree-walk.h"
 #include "object-name.h"
 
+const char *git_attr_tree;
+
 const char git_attr__true[] = "(builtin)true";
 const char git_attr__false[] = "\0(builtin)false";
 static const char git_attr__unknown[] = "(builtin)unknown";
@@ -806,35 +809,56 @@ static struct attr_stack *read_attr_from_blob(struct index_state *istate,
 static struct attr_stack *read_attr_from_index(struct index_state *istate,
 					       const char *path, unsigned flags)
 {
+	struct attr_stack *stack = NULL;
 	char *buf;
 	unsigned long size;
+	int sparse_dir_pos = -1;
 
 	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.
+	 * When handling sparse-checkouts, .gitattributes files
+	 * may reside within a sparse directory. We distinguish
+	 * whether a path exists directly in the index or not by
+	 * evaluating if 'pos' is negative.
+	 * If 'pos' is negative, the path is not directly present
+	 * in the index and is likely within a sparse directory.
+	 * For paths not in the index, The absolute value of 'pos'
+	 * minus 1 gives us the position where the path would be
+	 * inserted in lexicographic order within the index.
+	 * We then subtract another 1 from this value
+	 * (sparse_dir_pos = -pos - 2) to find the position of the
+	 * last index entry which is lexicographically smaller than
+	 * the path. This would be the sparse directory containing
+	 * the path. By identifying the sparse directory containing
+	 * the path, we can correctly read the attributes specified
+	 * in the .gitattributes file from the tree object of the
+	 * sparse directory.
 	 */
-	if (!path_in_cone_mode_sparse_checkout(path, istate))
-		return NULL;
+	if (!path_in_cone_mode_sparse_checkout(path, istate)) {
+		int pos = index_name_pos_sparse(istate, path, strlen(path));
 
-	buf = read_blob_data_from_index(istate, path, &size);
-	if (!buf)
-		return NULL;
-	if (size >= ATTR_MAX_FILE_SIZE) {
-		warning(_("ignoring overly large gitattributes blob '%s'"), path);
-		return NULL;
+		if (pos < 0)
+			sparse_dir_pos = -pos - 2;
 	}
 
-	return read_attr_from_buf(buf, path, flags);
+	if (sparse_dir_pos >= 0 &&
+	    S_ISSPARSEDIR(istate->cache[sparse_dir_pos]->ce_mode) &&
+	    !strncmp(istate->cache[sparse_dir_pos]->name, path, ce_namelen(istate->cache[sparse_dir_pos]))) {
+		const char *relative_path = path + ce_namelen(istate->cache[sparse_dir_pos]);
+		stack = read_attr_from_blob(istate, &istate->cache[sparse_dir_pos]->oid, relative_path, flags);
+	} else {
+		buf = read_blob_data_from_index(istate, path, &size);
+		if (!buf)
+			return NULL;
+		if (size >= ATTR_MAX_FILE_SIZE) {
+			warning(_("ignoring overly large gitattributes blob '%s'"), path);
+			return NULL;
+		}
+		stack = read_attr_from_buf(buf, path, flags);
+	}
+	return stack;
 }
 
 static struct attr_stack *read_attr(struct index_state *istate,
@@ -870,7 +894,7 @@ static struct attr_stack *read_attr(struct index_state *istate,
 	return res;
 }
 
-static const char *git_etc_gitattributes(void)
+const char *git_attr_system_file(void)
 {
 	static const char *system_wide;
 	if (!system_wide)
@@ -878,7 +902,7 @@ static const char *git_etc_gitattributes(void)
 	return system_wide;
 }
 
-static const char *get_home_gitattributes(void)
+const char *git_attr_global_file(void)
 {
 	if (!git_attributes_file)
 		git_attributes_file = xdg_config_home("attributes");
@@ -886,7 +910,7 @@ static const char *get_home_gitattributes(void)
 	return git_attributes_file;
 }
 
-static int git_attr_system(void)
+int git_attr_system_is_enabled(void)
 {
 	return !git_env_bool("GIT_ATTR_NOSYSTEM", 0);
 }
@@ -920,14 +944,14 @@ static void bootstrap_attr_stack(struct index_state *istate,
 	push_stack(stack, e, NULL, 0);
 
 	/* system-wide frame */
-	if (git_attr_system()) {
-		e = read_attr_from_file(git_etc_gitattributes(), flags);
+	if (git_attr_system_is_enabled()) {
+		e = read_attr_from_file(git_attr_system_file(), flags);
 		push_stack(stack, e, NULL, 0);
 	}
 
 	/* home directory */
-	if (get_home_gitattributes()) {
-		e = read_attr_from_file(get_home_gitattributes(), flags);
+	if (git_attr_global_file()) {
+		e = read_attr_from_file(git_attr_global_file(), flags);
 		push_stack(stack, e, NULL, 0);
 	}
 
@@ -1172,6 +1196,7 @@ static void collect_some_attrs(struct index_state *istate,
 }
 
 static const char *default_attr_source_tree_object_name;
+static int ignore_bad_attr_tree;
 
 void set_git_attr_source(const char *tree_object_name)
 {
@@ -1183,10 +1208,24 @@ static void compute_default_attr_source(struct object_id *attr_source)
 	if (!default_attr_source_tree_object_name)
 		default_attr_source_tree_object_name = getenv(GIT_ATTR_SOURCE_ENVIRONMENT);
 
+	if (!default_attr_source_tree_object_name && git_attr_tree) {
+		default_attr_source_tree_object_name = git_attr_tree;
+		ignore_bad_attr_tree = 1;
+	}
+
+	if (!default_attr_source_tree_object_name &&
+	    startup_info->have_repository &&
+	    is_bare_repository()) {
+		default_attr_source_tree_object_name = "HEAD";
+		ignore_bad_attr_tree = 1;
+	}
+
 	if (!default_attr_source_tree_object_name || !is_null_oid(attr_source))
 		return;
 
-	if (repo_get_oid_treeish(the_repository, default_attr_source_tree_object_name, attr_source))
+	if (repo_get_oid_treeish(the_repository,
+				 default_attr_source_tree_object_name,
+				 attr_source) && !ignore_bad_attr_tree)
 		die(_("bad --attr-source or GIT_ATTR_SOURCE"));
 }