fix(historian): #691.4 review — Null reports SupportsReverseEvents = true, like raw

The null source has no history in either direction; reporting false made the server walk an empty reverse events read back through three empty forward reads. It now answers the reverse overload with the empty result itself (guard test unchanged: it still declares both members).
2026-10-12 17:37:32 -04:00
parent d28e3e64f1
commit 574c3aa1b0
5 changed files with 16 additions and 17 deletions
@@ -5291,7 +5291,7 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
                reverse = startUtc > endUtc;
            }

-            // A reverse read on a backend that cannot read newest-first (Gateway, Null) is never sent there (#675 refused it
+            // A reverse read on a backend that cannot read newest-first (the Gateway) is never sent there (#675 refused it
            // here); since #691.4 it is walked back from bounded forward reads — the raw walk (#686), with ties ordered by
            // EventId because the gateway orders by event time only. Decided by the capability, not by catching an
            // exception, so a NotSupportedException thrown from inside a backend stays a backend fault.