From 60440d72db4c9f2fc05b841813e72159c4f08928 Mon Sep 17 00:00:00 2001 From: Jonathan Nieder Date: Fri, 3 Jan 2020 16:13:31 -0800 Subject: [PATCH] sha1-file: document how to use pretend_object_file Like in-memory alternates, pretend_object_file contains a trap for the unwary: careless callers can use it to create references to an object that does not exist in the on-disk object store. Add a comment documenting how to use the function without risking such problems. The only current caller is blame, which uses pretend_object_file to create an in-memory commit representing the working tree state. Noticed during a discussion of how to safely use this function in operations like "git merge" which, unlike blame, are not read-only. Inspired-by: Junio C Hamano Signed-off-by: Jonathan Nieder Signed-off-by: Junio C Hamano --- object-store.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/object-store.h b/object-store.h index 7f7b3cdd80..f91e0c99b4 100644 --- a/object-store.h +++ b/object-store.h @@ -187,6 +187,14 @@ int hash_object_file_literally(const void *buf, unsigned long len, const char *type, struct object_id *oid, unsigned flags); +/* + * Add an object file to the in-memory object store, without writing it + * to disk. + * + * Callers are responsible for calling write_object_file to record the + * object in persistent storage before writing any other new objects + * that reference it. + */ int pretend_object_file(void *, unsigned long, enum object_type, struct object_id *oid);