Merge branch 'ps/refname-avail-check-optim'

The code paths to check whether a refname X is available (by seeing
if another ref X/Y exists, etc.) have been optimized.

* ps/refname-avail-check-optim:
  refs: reuse iterators when determining refname availability
  refs/iterator: implement seeking for files iterators
  refs/iterator: implement seeking for packed-ref iterators
  refs/iterator: implement seeking for ref-cache iterators
  refs/iterator: implement seeking for reftable iterators
  refs/iterator: implement seeking for merged iterators
  refs/iterator: provide infrastructure to re-seek iterators
  refs/iterator: separate lifecycle from iteration
  refs: stop re-verifying common prefixes for availability
  refs/files: batch refname availability checks for initial transactions
  refs/files: batch refname availability checks for normal transactions
  refs/reftable: batch refname availability checks
  refs: introduce function to batch refname availability checks
  builtin/update-ref: skip ambiguity checks when parsing object IDs
  object-name: allow skipping ambiguity checks in `get_oid()` family
  object-name: introduce `repo_get_oid_with_flags()`

1 files changed, 15 insertions, 5 deletions

diff --git a/refs/debug.c b/refs/debug.c
index fbc4df08b4..5390fa9c18 100644
--- a/refs/debug.c
+++ b/refs/debug.c
@@ -169,6 +169,16 @@ static int debug_ref_iterator_advance(struct ref_iterator *ref_iterator)
 	return res;
 }
 
+static int debug_ref_iterator_seek(struct ref_iterator *ref_iterator,
+				   const char *prefix)
+{
+	struct debug_ref_iterator *diter =
+		(struct debug_ref_iterator *)ref_iterator;
+	int res = diter->iter->vtable->seek(diter->iter, prefix);
+	trace_printf_key(&trace_refs, "iterator_seek: %s: %d\n", prefix ? prefix : "", res);
+	return res;
+}
+
 static int debug_ref_iterator_peel(struct ref_iterator *ref_iterator,
 				   struct object_id *peeled)
 {
@@ -179,19 +189,19 @@ static int debug_ref_iterator_peel(struct ref_iterator *ref_iterator,
 	return res;
 }
 
-static int debug_ref_iterator_abort(struct ref_iterator *ref_iterator)
+static void debug_ref_iterator_release(struct ref_iterator *ref_iterator)
 {
 	struct debug_ref_iterator *diter =
 		(struct debug_ref_iterator *)ref_iterator;
-	int res = diter->iter->vtable->abort(diter->iter);
-	trace_printf_key(&trace_refs, "iterator_abort: %d\n", res);
-	return res;
+	diter->iter->vtable->release(diter->iter);
+	trace_printf_key(&trace_refs, "iterator_abort\n");
 }
 
 static struct ref_iterator_vtable debug_ref_iterator_vtable = {
 	.advance = debug_ref_iterator_advance,
+	.seek = debug_ref_iterator_seek,
 	.peel = debug_ref_iterator_peel,
-	.abort = debug_ref_iterator_abort,
+	.release = debug_ref_iterator_release,
 };
 
 static struct ref_iterator *