reftable/merged: handle allocation failures in `merged_table_init_iter()`

Handle allocation failures in `merged_table_init_iter()`. While at it,
merge `merged_iter_init()` into the function. It only has a single
caller and merging them makes it easier to handle allocation failures
consistently.

This change also requires us to adapt `reftable_stack_init_*_iterator()`
to bubble up the new error codes of `merged_table_iter_init()`. Adapt
callsites accordingly.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 31 insertions, 8 deletions

diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 3e63833ce4..9c2c695b13 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -1307,7 +1307,9 @@ static int write_transaction_table(struct reftable_writer *writer, void *cb_data
 			struct reftable_log_record log = {0};
 			struct reftable_iterator it = {0};
 
-			reftable_stack_init_log_iterator(arg->stack, &it);
+			ret = reftable_stack_init_log_iterator(arg->stack, &it);
+			if (ret < 0)
+				goto done;
 
 			/*
 			 * When deleting refs we also delete all reflog entries
@@ -1677,7 +1679,10 @@ static int write_copy_table(struct reftable_writer *writer, void *cb_data)
 	 * copy over all log entries from the old reflog. Last but not least,
 	 * when renaming we also have to delete all the old reflog entries.
 	 */
-	reftable_stack_init_log_iterator(arg->stack, &it);
+	ret = reftable_stack_init_log_iterator(arg->stack, &it);
+	if (ret < 0)
+		goto done;
+
 	ret = reftable_iterator_seek_log(&it, arg->oldname);
 	if (ret < 0)
 		goto done;
@@ -1898,7 +1903,10 @@ static struct reftable_reflog_iterator *reflog_iterator_for_stack(struct reftabl
 	if (ret < 0)
 		goto done;
 
-	reftable_stack_init_log_iterator(stack, &iter->iter);
+	ret = reftable_stack_init_log_iterator(stack, &iter->iter);
+	if (ret < 0)
+		goto done;
+
 	ret = reftable_iterator_seek_log(&iter->iter, "");
 	if (ret < 0)
 		goto done;
@@ -1965,7 +1973,10 @@ static int reftable_be_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 	if (refs->err < 0)
 		return refs->err;
 
-	reftable_stack_init_log_iterator(stack, &it);
+	ret = reftable_stack_init_log_iterator(stack, &it);
+	if (ret < 0)
+		goto done;
+
 	ret = reftable_iterator_seek_log(&it, refname);
 	while (!ret) {
 		ret = reftable_iterator_next_log(&it, &log);
@@ -1981,6 +1992,7 @@ static int reftable_be_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 			break;
 	}
 
+done:
 	reftable_log_record_release(&log);
 	reftable_iterator_destroy(&it);
 	return ret;
@@ -2002,7 +2014,10 @@ static int reftable_be_for_each_reflog_ent(struct ref_store *ref_store,
 	if (refs->err < 0)
 		return refs->err;
 
-	reftable_stack_init_log_iterator(stack, &it);
+	ret = reftable_stack_init_log_iterator(stack, &it);
+	if (ret < 0)
+		goto done;
+
 	ret = reftable_iterator_seek_log(&it, refname);
 	while (!ret) {
 		struct reftable_log_record log = {0};
@@ -2052,7 +2067,10 @@ static int reftable_be_reflog_exists(struct ref_store *ref_store,
 	if (ret < 0)
 		goto done;
 
-	reftable_stack_init_log_iterator(stack, &it);
+	ret = reftable_stack_init_log_iterator(stack, &it);
+	if (ret < 0)
+		goto done;
+
 	ret = reftable_iterator_seek_log(&it, refname);
 	if (ret < 0)
 		goto done;
@@ -2158,7 +2176,9 @@ static int write_reflog_delete_table(struct reftable_writer *writer, void *cb_da
 
 	reftable_writer_set_limits(writer, ts, ts);
 
-	reftable_stack_init_log_iterator(arg->stack, &it);
+	ret = reftable_stack_init_log_iterator(arg->stack, &it);
+	if (ret < 0)
+		goto out;
 
 	/*
 	 * In order to delete a table we need to delete all reflog entries one
@@ -2182,6 +2202,7 @@ static int write_reflog_delete_table(struct reftable_writer *writer, void *cb_da
 		ret = reftable_writer_add_log(writer, &tombstone);
 	}
 
+out:
 	reftable_log_record_release(&log);
 	reftable_iterator_destroy(&it);
 	return ret;
@@ -2320,7 +2341,9 @@ static int reftable_be_reflog_expire(struct ref_store *ref_store,
 	if (ret < 0)
 		goto done;
 
-	reftable_stack_init_log_iterator(stack, &it);
+	ret = reftable_stack_init_log_iterator(stack, &it);
+	if (ret < 0)
+		goto done;
 
 	ret = reftable_iterator_seek_log(&it, refname);
 	if (ret < 0)