reftable: mark unused parameters in virtual functions

The reftable code uses a lot of virtual function pointers, but many of
the concrete implementations do not need all of the parameters.

For the most part these are obviously fine to just mark as UNUSED (e.g.,
the empty_iterator functions unsurprisingly do not do anything). Here
are a few cases where I dug a little deeper (but still ended up just
marking them UNUSED):

  - the iterator exclude_patterns is best-effort and optional (though it
    would be nice to support in the long run as an optimization)

  - ignoring the ref_store in many transaction functions is unexpected,
    but works because the ref_transaction itself carries enough
    information to do what we need.

  - ignoring "err" for in some cases (e.g., transaction abort) is OK
    because we do not return any errors. It is a little odd for
    reftable_be_create_reflog(), though, since we do return errors
    there. We should perhaps be creating string error messages at this
    layer, but I've punted on that for now.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 7 deletions

diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 7337d4422d..a2de39f2ca 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -614,7 +614,7 @@ done:
 
 static struct ref_iterator *reftable_be_iterator_begin(struct ref_store *ref_store,
 						       const char *prefix,
-						       const char **exclude_patterns,
+						       const char **exclude_patterns UNUSED,
 						       unsigned int flags)
 {
 	struct reftable_ref_iterator *main_iter, *worktree_iter;
@@ -1123,9 +1123,9 @@ done:
 	return ret;
 }
 
-static int reftable_be_transaction_abort(struct ref_store *ref_store,
+static int reftable_be_transaction_abort(struct ref_store *ref_store UNUSED,
 					 struct ref_transaction *transaction,
-					 struct strbuf *err)
+					 struct strbuf *err UNUSED)
 {
 	struct reftable_transaction_data *tx_data = transaction->backend_data;
 	free_transaction_data(tx_data);
@@ -1315,7 +1315,7 @@ done:
 	return ret;
 }
 
-static int reftable_be_transaction_finish(struct ref_store *ref_store,
+static int reftable_be_transaction_finish(struct ref_store *ref_store UNUSED,
 					  struct ref_transaction *transaction,
 					  struct strbuf *err)
 {
@@ -1726,8 +1726,8 @@ static int reftable_reflog_iterator_advance(struct ref_iterator *ref_iterator)
 	return ITER_OK;
 }
 
-static int reftable_reflog_iterator_peel(struct ref_iterator *ref_iterator,
-						 struct object_id *peeled)
+static int reftable_reflog_iterator_peel(struct ref_iterator *ref_iterator UNUSED,
+					 struct object_id *peeled UNUSED)
 {
 	BUG("reftable reflog iterator cannot be peeled");
 	return -1;
@@ -1988,7 +1988,7 @@ done:
 
 static int reftable_be_create_reflog(struct ref_store *ref_store,
 				     const char *refname,
-				     struct strbuf *errmsg)
+				     struct strbuf *errmsg UNUSED)
 {
 	struct reftable_ref_store *refs =
 		reftable_be_downcast(ref_store, REF_STORE_WRITE, "create_reflog");