[PATCH 1/6] Add docstrings for lookup_replace_object() and do_lookup_replace_object()

@@ -788,13 +788,29 @@ static inline void *read_sha1_file(const unsigned char *sha1, enum object_type *
 {
 	return read_sha1_file_extended(sha1, type, size, LOOKUP_REPLACE_OBJECT);
 }
+
+/*
+ * If a replacement for object sha1 has been set up, return the
+ * replacement object's name (replaced recursively, if necessary).
+ * The return value is either sha1 or a pointer to a
+ * permanently-allocated value.  This function always respects replace
+ * references, regardless of the value of check_replace_refs.
+ */
 extern const unsigned char *do_lookup_replace_object(const unsigned char *sha1);
+
+/*
+ * If object sha1 should be replaced, return the replacement object's
+ * name.  This function is similar to do_lookup_replace_object(),
+ * except that it when object replacement is suppressed, it always
+ * returns its argument unchanged.
+ */
 static inline const unsigned char *lookup_replace_object(const unsigned char *sha1)
 {
 	if (!read_replace_refs)
 		return sha1;
 	return do_lookup_replace_object(sha1);
 }
+
 static inline const unsigned char *lookup_replace_object_extended(const unsigned char *sha1, unsigned flag)
 {
 	if (!(flag & LOOKUP_REPLACE_OBJECT))