refs.h: clarify docstring for the ref_transaction_update()-related fns

In particular, make it clear that they make copies of the sha1 arguments. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Michael Haggerty committed May 22, 2017 at 16:17 UTC fd2ce9c01c91a093fbc8f7e444d4d80c0d89432a
1 file changed +13
refs.h
+13
@@ -427,6 +427,19 @@ struct ref_transaction *ref_transaction_begin(struct strbuf *err);
427 *
428 * refname -- the name of the reference to be affected.
429 *
430 + * new_sha1 -- the SHA-1 that should be set to be the new value of
431 + * the reference. Some functions allow this parameter to be
432 + * NULL, meaning that the reference is not changed, or
433 + * null_sha1, meaning that the reference should be deleted. A
434 + * copy of this value is made in the transaction.
435 + *
436 + * old_sha1 -- the SHA-1 value that the reference must have before
437 + * the update. Some functions allow this parameter to be NULL,
438 + * meaning that the old value of the reference is not checked,
439 + * or null_sha1, meaning that the reference must not exist
440 + * before the update. A copy of this value is made in the
441 + * transaction.
442 + *
443 * flags -- flags affecting the update, passed to
444 * update_ref_lock(). Can be REF_NODEREF, which means that
445 * symbolic references should not be followed.