fix(m9/T30): empty-state guard keys off resolved fields (top-level \$ref); shift list raw-text on item removal

src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Shared/ParameterValueForm.razor

@@ -18,7 +18,7 @@
     values.
 *@
 
-@if (_shapes.Count == 0)
+@if (_topLevelFields.Count == 0)
 {
     <div class="text-muted small fst-italic">No parameters declared.</div>
 }
@@ -399,18 +399,47 @@ else
         await Emit();
     }
 
-    // After a removal, item paths above the removed index shift down by one; clear
+    // After a removal at removedIndex, paths for items above that index shift down
-    // their stale raw-text/error entries so the re-rendered rows read fresh.
+    // by one. Mirror the value-list RemoveAt by: (1) for each index > removedIndex
+    // found in a dict, re-key it as index-1; (2) clear the now-vacated top slot
+    // (the original highest index). Items below the removed index are unaffected.
     private void ShiftListState(string path, int removedIndex)
+    {
+        ShiftDict(_rawText, path, removedIndex);
+        ShiftDict(_parseErrors, path, removedIndex);
+    }
+
+    private static void ShiftDict(Dictionary<string, string> dict, string path, int removedIndex)
     {
         var prefix = $"{path}[";
-        foreach (var key in _rawText.Keys.Where(k => k.StartsWith(prefix, StringComparison.Ordinal)).ToList())
+        // Collect keys under this list prefix, parse the item index, and build the
+        // shift map in one pass so in-place mutation does not interfere with iteration.
+        var toShift = new List<(string Key, int ItemIndex, string Suffix)>();
+        foreach (var key in dict.Keys)
         {
-            _rawText.Remove(key);
+            if (!key.StartsWith(prefix, StringComparison.Ordinal)) continue;
+            // Extract the integer after the '['.
+            var rest = key.AsSpan(prefix.Length); // e.g. "2]" or "2].field"
+            var closePos = rest.IndexOf(']');
+            if (closePos < 0) continue;
+            if (!int.TryParse(rest[..closePos], System.Globalization.NumberStyles.Integer,
+                    System.Globalization.CultureInfo.InvariantCulture, out var idx)) continue;
+            // Only touch items ABOVE the removed index; items at lower indices are stable.
+            if (idx <= removedIndex) continue;
+            var suffix = rest[(closePos + 1)..].ToString(); // everything after ']'
+            toShift.Add((key, idx, suffix));
         }
-        foreach (var key in _parseErrors.Keys.Where(k => k.StartsWith(prefix, StringComparison.Ordinal)).ToList())
+
+        // Apply: remove old key, write shifted key. Higher indices first so we never
+        // overwrite a key that is itself still pending a shift (would happen if we
+        // iterated lowest-to-highest and the same path base appeared at consecutive
+        // indices). Processing highest → lowest avoids the collision.
+        foreach (var (key, idx, suffix) in toShift.OrderByDescending(t => t.ItemIndex))
         {
-            _parseErrors.Remove(key);
+            var value = dict[key];
+            dict.Remove(key);
+            var shiftedKey = $"{path}[{idx - 1}]{suffix}";
+            dict[shiftedKey] = value;
         }
     }
 

tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Design/ParameterValueFormTests.cs

@@ -184,4 +184,102 @@ public class ParameterValueFormTests : BunitContext
         // A field-level error class is shown.
         Assert.NotEmpty(cut.FindAll(".text-danger"));
     }
+
+    // M1 — top-level $ref: empty-state guard must key off resolved fields, not _shapes
+    [Fact]
+    public void TopLevelRef_ResolvesToObject_RendersFields_NotEmptyState()
+    {
+        // Library entry "SomeObject" resolves to an object with two fields.
+        const string libSchema = """
+            {
+              "type": "object",
+              "properties": {
+                "code": { "type": "integer" },
+                "label": { "type": "string" }
+              },
+              "required": ["code"]
+            }
+            """;
+        _library.GetSchemaMapAsync(Arg.Any<CancellationToken>())
+            .Returns(new Dictionary<string, string> { ["SomeObject"] = libSchema });
+
+        // The parameter definitions IS a top-level $ref — no "properties" key at the
+        // root level, so _shapes (JsonSchemaShapeParser) stays empty.
+        const string paramSchema = """{"$ref":"lib:SomeObject"}""";
+
+        var cut = Render<ParameterValueForm>(p => p
+            .Add(x => x.ParameterDefinitions, paramSchema)
+            .Add(x => x.Values, new Dictionary<string, object?>()));
+
+        // Must NOT show the empty-state message.
+        Assert.DoesNotContain("No parameters declared", cut.Markup);
+
+        // Must render the resolved object's two fields.
+        Assert.Contains("code", cut.Markup);
+        Assert.Contains("label", cut.Markup);
+        // Integer and String inputs are present.
+        Assert.NotEmpty(cut.FindAll("input[type=number]"));
+        Assert.NotEmpty(cut.FindAll("input[type=text]"));
+    }
+
+    // I1 — list item removal: in-progress raw text of later items must SHIFT, not wipe.
+    // Uses a list-of-objects schema so sub-field raw-text entries (e.g. "rows[1].qty")
+    // persist in the rendered list (the LIST SLOT stays; only the nested field value
+    // is cleared on invalid input, not the containing dict). This is the scenario the
+    // ShiftDict fix is designed for: "rows[1].qty" → "rows[0].qty" when rows[0] is
+    // removed, so the error/raw-text follows the item rather than being wiped.
+    [Fact]
+    public void ListItemRemoval_ShiftsNestedRawTextOfLaterItems_NotWiped()
+    {
+        // List of objects, each with an integer "qty" field.
+        const string schema = """
+            {
+              "type": "object",
+              "properties": {
+                "rows": {
+                  "type": "array",
+                  "items": {
+                    "type": "object",
+                    "properties": {
+                      "qty": { "type": "integer" }
+                    }
+                  }
+                }
+              }
+            }
+            """;
+
+        var cut = Render<ParameterValueForm>(p => p
+            .Add(x => x.ParameterDefinitions, schema)
+            .Add(x => x.Values, new Dictionary<string, object?>())
+            .Add(x => x.ValuesChanged, _ => { }));
+
+        // Add two object items.
+        var addButton = cut.Find("button.param-list-add");
+        addButton.Click();  // rows[0]
+        addButton.Click();  // rows[1]
+
+        // Commit a valid qty in rows[0].
+        var numberInputs = cut.FindAll("input[type=number]");
+        numberInputs[0].Input("5");
+
+        // Enter an INVALID qty in rows[1] — parks raw text "abc" in _rawText["rows[1].qty"]
+        // and _parseErrors["rows[1].qty"]. The LIST SLOT rows[1] is preserved (only the
+        // nested field value is cleared, not the containing dict).
+        numberInputs = cut.FindAll("input[type=number]");
+        numberInputs[1].Input("abc");
+
+        // The error for rows[1].qty is visible before removal.
+        Assert.NotEmpty(cut.FindAll(".text-danger"));
+
+        // Remove rows[0]. With the fix, "rows[1].qty" raw-text/error entries shift to
+        // "rows[0].qty", following the item. Without the fix they are wiped and the
+        // item renders as if freshly added (no error).
+        cut.Find("button.param-list-remove").Click();
+
+        // After removal, the remaining item (formerly rows[1]) must still show the
+        // invalid-field error. Two remove buttons collapsed to one; one item renders.
+        Assert.Single(cut.FindAll("button.param-list-remove"));
+        Assert.NotEmpty(cut.FindAll(".text-danger"));
+    }
 }