fix(r2-01): surface connect-timeout as TimeoutException, not OCE — poll loops no longer die on unreachable-host outages (STAB-14, task 3)

archreview/plans/R2-01-s7-fault-hardening-plan.md.tasks.json

@@ -22,7 +22,7 @@
     {
       "id": 3,
       "subject": "GREEN: EnsureConnectedAsync + InitializeAsync connect-timeout OCE -> TimeoutException conversion (STAB-14 root fix)",
-      "status": "pending",
+      "status": "completed",
       "blockedBy": [1, 2]
     },
     {

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7/S7Driver.cs

@@ -187,6 +187,16 @@ public sealed class S7Driver
                 cts.CancelAfter(_options.Timeout);
                 await plc.OpenAsync(cts.Token).ConfigureAwait(false);
             }
+            catch (OperationCanceledException) when (!cancellationToken.IsCancellationRequested)
+            {
+                // The linked CancelAfter fired — a connect TIMEOUT, not a caller cancellation.
+                // Surface it as a TimeoutException so init-time and reconnect-time timeouts report
+                // the same exception type (STAB-14 consistency); the outer catch still faults health.
+                try { plc.Dispose(); } catch { }
+                throw new TimeoutException(
+                    $"S7 connect to {_options.Host}:{_options.Port} timed out after " +
+                    $"{(int)_options.Timeout.TotalMilliseconds} ms.");
+            }
             catch
             {
                 // Dispose the partially-constructed connection so a failed init doesn't leak it
@@ -1205,6 +1215,17 @@ public sealed class S7Driver
             cts.CancelAfter(_options.Timeout);
             await plc.OpenAsync(cts.Token).ConfigureAwait(false);
         }
+        catch (OperationCanceledException) when (!ct.IsCancellationRequested)
+        {
+            // The linked CancelAfter fired — a connect TIMEOUT, not a caller cancellation.
+            // Surface it as a connection FAILURE (TimeoutException) so callers route it through
+            // their degrade paths: an escaping OCE reads as teardown and permanently killed the
+            // subscription poll loops (STAB-14, the unreachable-host regression in the Crit-3 fix).
+            try { plc.Dispose(); } catch { /* best-effort */ }
+            throw new TimeoutException(
+                $"S7 connect to {_options.Host}:{_options.Port} timed out after " +
+                $"{(int)_options.Timeout.TotalMilliseconds} ms.");
+        }
         catch
         {
             try { plc.Dispose(); } catch { /* best-effort */ }