refs: make sha1 output parameter of refs_resolve_ref_unsafe() optional

Allow callers of refs_resolve_ref_unsafe() to pass NULL if they don't
need the resolved hash value.  We already allow the same for the flags
parameter.  This new leniency is inherited by the various wrappers like
resolve_ref_unsafe().

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/refs.c b/refs.c
index c30f4c3..36439fd 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -1396,9 +1396,12 @@ const char *refs_resolve_ref_unsafe(struct ref_store *refs,
                                    unsigned char *sha1, int *flags)
 {
        static struct strbuf sb_refname = STRBUF_INIT;
+       struct object_id unused_oid;
        int unused_flags;
        int symref_count;
 
+       if (!sha1)
+               sha1 = unused_oid.hash;
        if (!flags)
                flags = &unused_flags;
 

diff --git a/refs.h b/refs.h
index 78a2640..996d4ea 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -10,10 +10,11 @@ struct worktree;
 /*
  * Resolve a reference, recursively following symbolic refererences.
  *
- * Store the referred-to object's name in sha1 and return the name of
- * the non-symbolic reference that ultimately pointed at it.  The
- * return value, if not NULL, is a pointer into either a static buffer
- * or the input ref.
+ * Return the name of the non-symbolic reference that ultimately pointed
+ * at the resolved object name.  The return value, if not NULL, is a
+ * pointer into either a static buffer or the input ref.
+ *
+ * If sha1 is non-NULL, store the referred-to object's name in it.
  *
  * If the reference cannot be resolved to an object, the behavior
  * depends on the RESOLVE_REF_READING flag: