attr.c: read .gitattributes from index as well.

This makes .gitattributes files to be read from the index when
they are not checked out to the work tree.  This is in line with
the way we always allowed low-level tools to operate in sparsely
checked out work tree in a reasonable way.

It swaps the order of new file creation and converting the blob
to work tree representation; otherwise when we are in the middle
of checking out .gitattributes we would notice an empty but
unwritten .gitattributes file in the work tree and will ignore
the copy in the index.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 59 insertions, 2 deletions

diff --git a/attr.c b/attr.c
index 8d778f1d2..129399310 100644
--- a/attr.c
+++ b/attr.c
@@ -336,13 +336,70 @@ static struct attr_stack *read_attr_from_file(const char *path, int macro_ok)
 	return res;
 }
 
+static void *read_index_data(const char *path)
+{
+	int pos, len;
+	unsigned long sz;
+	enum object_type type;
+	void *data;
+
+	len = strlen(path);
+	pos = cache_name_pos(path, len);
+	if (pos < 0) {
+		/*
+		 * We might be in the middle of a merge, in which
+		 * case we would read stage #2 (ours).
+		 */
+		int i;
+		for (i = -pos - 1;
+		     (pos < 0 && i < active_nr &&
+		      !strcmp(active_cache[i]->name, path));
+		     i++)
+			if (ce_stage(active_cache[i]) == 2)
+				pos = i;
+	}
+	if (pos < 0)
+		return NULL;
+	data = read_sha1_file(active_cache[pos]->sha1, &type, &sz);
+	if (!data || type != OBJ_BLOB) {
+		free(data);
+		return NULL;
+	}
+	return data;
+}
+
 static struct attr_stack *read_attr(const char *path, int macro_ok)
 {
 	struct attr_stack *res;
+	char *buf, *sp;
+	int lineno = 0;
 
 	res = read_attr_from_file(path, macro_ok);
-	if (!res)
-		res = xcalloc(1, sizeof(*res));
+	if (res)
+		return res;
+
+	res = xcalloc(1, sizeof(*res));
+
+	/*
+	 * There is no checked out .gitattributes file there, but
+	 * we might have it in the index.  We allow operation in a
+	 * sparsely checked out work tree, so read from it.
+	 */
+	buf = read_index_data(path);
+	if (!buf)
+		return res;
+
+	for (sp = buf; *sp; ) {
+		char *ep;
+		int more;
+		for (ep = sp; *ep && *ep != '\n'; ep++)
+			;
+		more = (*ep == '\n');
+		*ep = '\0';
+		handle_attr_line(res, sp, path, ++lineno, macro_ok);
+		sp = ep + more;
+	}
+	free(buf);
 	return res;
 }