fix(centralui): NodeBrowserDialog — reset load/expand spinner on error + clear stale failure on blank search (T15)

src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Dialogs/NodeBrowserDialog.razor

@@ -211,8 +211,15 @@
         {
             node.Loading = true;
             StateHasChanged();
-            var result = await BrowseService.BrowseChildrenAsync(_runtimeSiteId, _runtimeConnectionName, node.NodeId);
+            BrowseNodeResult result;
-            node.Loading = false;
+            try
+            {
+                result = await BrowseService.BrowseChildrenAsync(_runtimeSiteId, _runtimeConnectionName, node.NodeId);
+            }
+            finally
+            {
+                node.Loading = false;
+            }
 
             if (result.Failure is not null)
             {
@@ -237,9 +244,16 @@
 
         node.Loading = true;
         StateHasChanged();
-        var result = await BrowseService.BrowseChildrenAsync(
+        BrowseNodeResult result;
-            _runtimeSiteId, _runtimeConnectionName, node.NodeId, node.ContinuationToken);
+        try
-        node.Loading = false;
+        {
+            result = await BrowseService.BrowseChildrenAsync(
+                _runtimeSiteId, _runtimeConnectionName, node.NodeId, node.ContinuationToken);
+        }
+        finally
+        {
+            node.Loading = false;
+        }
 
         if (result.Failure is not null)
         {
@@ -266,6 +280,8 @@
             _searchActive = false;
             _searchResults = new();
             _searchCapReached = false;
+            _failure = null;
+            _failureMessage = "";
             StateHasChanged();
             return;
         }

tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Components/NodeBrowserDialogSearchTests.cs

@@ -124,4 +124,32 @@ public class NodeBrowserDialogSearchTests : BunitContext
         cut.Find("[data-test=node-search-button]").Click();
         Assert.Empty(cut.FindAll("[data-test=node-search-result]"));
     }
+
+    [Fact]
+    public void BlankQueryAfterFailure_ClearsStaleFailureAlert()
+    {
+        // First search returns a failure so the alert banner appears.
+        _browse.SearchAsync(
+                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(),
+                Arg.Any<int>(), Arg.Any<int>(), Arg.Any<CancellationToken>())
+            .Returns(new SearchAddressSpaceResult(
+                Matches: Array.Empty<AddressSpaceMatch>(),
+                CapReached: false,
+                Failure: new BrowseFailure(BrowseFailureKind.Timeout, "timed out")));
+
+        var cut = RenderShown(out _);
+
+        cut.Find("[data-test=node-search-input]").Input("Pump1");
+        cut.Find("[data-test=node-search-button]").Click();
+
+        // The failure alert must be visible after the failed search.
+        Assert.NotEmpty(cut.FindAll(".alert-danger"));
+
+        // User clears the query and searches again (blank).
+        cut.Find("[data-test=node-search-input]").Input("");
+        cut.Find("[data-test=node-search-button]").Click();
+
+        // Stale failure alert must be gone.
+        Assert.Empty(cut.FindAll(".alert-danger"));
+    }
 }