refs: support rejection in batch updates during F/D checks

The `refs_verify_refnames_available()` is used to batch check refnames
for F/D conflicts. While this is the more performant alternative than
its individual version, it does not provide rejection capabilities on a
single update level. For batched updates, this would mean a rejection of
the entire transaction whenever one reference has a F/D conflict.

Modify the function to call `ref_transaction_maybe_set_rejected()` to
check if a single update can be rejected. Since this function is only
internally used within 'refs/' and we want to pass in a `struct
ref_transaction *` as a variable. We also move and mark
`refs_verify_refnames_available()` to 'refs-internal.h' to be an
internal function.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 34 insertions, 3 deletions

diff --git a/refs.c b/refs.c
index 6edc79262a..498aec3fc0 100644
--- a/refs.c
+++ b/refs.c
@@ -2540,6 +2540,7 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 					  const struct string_list *refnames,
 					  const struct string_list *extras,
 					  const struct string_list *skip,
+					  struct ref_transaction *transaction,
 					  unsigned int initial_transaction,
 					  struct strbuf *err)
 {
@@ -2547,6 +2548,7 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 	struct strbuf referent = STRBUF_INIT;
 	struct string_list_item *item;
 	struct ref_iterator *iter = NULL;
+	struct strset conflicting_dirnames;
 	struct strset dirnames;
 	int ret = REF_TRANSACTION_ERROR_NAME_CONFLICT;
 
@@ -2557,9 +2559,11 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 
 	assert(err);
 
+	strset_init(&conflicting_dirnames);
 	strset_init(&dirnames);
 
 	for_each_string_list_item(item, refnames) {
+		const size_t *update_idx = (size_t *)item->util;
 		const char *refname = item->string;
 		const char *extra_refname;
 		struct object_id oid;
@@ -2597,14 +2601,30 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 				continue;
 
 			if (!initial_transaction &&
-			    !refs_read_raw_ref(refs, dirname.buf, &oid, &referent,
-					       &type, &ignore_errno)) {
+			    (strset_contains(&conflicting_dirnames, dirname.buf) ||
+			     !refs_read_raw_ref(refs, dirname.buf, &oid, &referent,
+						       &type, &ignore_errno))) {
+				if (transaction && ref_transaction_maybe_set_rejected(
+					    transaction, *update_idx,
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					strset_remove(&dirnames, dirname.buf);
+					strset_add(&conflicting_dirnames, dirname.buf);
+					continue;
+				}
+
 				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
 					    dirname.buf, refname);
 				goto cleanup;
 			}
 
 			if (extras && string_list_has_string(extras, dirname.buf)) {
+				if (transaction && ref_transaction_maybe_set_rejected(
+					    transaction, *update_idx,
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT)) {
+					strset_remove(&dirnames, dirname.buf);
+					continue;
+				}
+
 				strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
 					    refname, dirname.buf);
 				goto cleanup;
@@ -2637,6 +2657,11 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 				    string_list_has_string(skip, iter->refname))
 					continue;
 
+				if (transaction && ref_transaction_maybe_set_rejected(
+					    transaction, *update_idx,
+					    REF_TRANSACTION_ERROR_NAME_CONFLICT))
+					continue;
+
 				strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
 					    iter->refname, refname);
 				goto cleanup;
@@ -2648,6 +2673,11 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 
 		extra_refname = find_descendant_ref(dirname.buf, extras, skip);
 		if (extra_refname) {
+			if (transaction && ref_transaction_maybe_set_rejected(
+				    transaction, *update_idx,
+				    REF_TRANSACTION_ERROR_NAME_CONFLICT))
+				continue;
+
 			strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
 				    refname, extra_refname);
 			goto cleanup;
@@ -2659,6 +2689,7 @@ enum ref_transaction_error refs_verify_refnames_available(struct ref_store *refs
 cleanup:
 	strbuf_release(&referent);
 	strbuf_release(&dirname);
+	strset_clear(&conflicting_dirnames);
 	strset_clear(&dirnames);
 	ref_iterator_free(iter);
 	return ret;
@@ -2679,7 +2710,7 @@ enum ref_transaction_error refs_verify_refname_available(
 	};
 
 	return refs_verify_refnames_available(refs, &refnames, extras, skip,
-					      initial_transaction, err);
+					      NULL, initial_transaction, err);
 }
 
 struct do_for_each_reflog_help {