Publish shared FXML diagnostics and integrate IntelliJ Problems

Navigate authoritative FXML locations, withdraw stale results and preserve host Undo/Redo. Include editor ownership in native problem identity so equal diagnostics from separate owners survive independent cleanup. Qualify both hosts automatically.

designer-kit-ui/src/main/java/de/neitzel/fxdesigner/kit/DesignerPane.java

@@ -121,6 +121,11 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
   private BindingEditor bindingEditor, computedEditor, repeatEditor;
   private TableEditor tableEditor;
   private ReferenceEditor referenceEditor;
+  private DiagnosticsPane diagnosticsPane;
+  private final String diagnosticsOwner = java.util.UUID.randomUUID().toString();
+  private long diagnosticsRevision = -1;
+  private SplitPane sourceSplit;
+  private Integer pendingSourceOffset;
   private String pendingReferenceValidation;
   private String validatedSource, validatingSource;
   private boolean validationPreview;
@@ -220,6 +225,8 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
         new TableEditor(
             this::editTable, this::navigateComponent, values -> validateBindings(values, false));
     referenceEditor = new ReferenceEditor(file.toUri().toString(), this::editStructure);
+    diagnosticsPane =
+        new DiagnosticsPane(() -> validateBindings(null, false), this::navigateDiagnostic);
     bindingBrowser =
         new BindingBrowser(
             this::discoverBindings,
@@ -346,6 +353,7 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
           }
         });
     var split = new SplitPane(source, design);
+    sourceSplit = split;
     split.setDividerPositions(.3);
     var modes =
         new ToolBar(
@@ -372,13 +380,21 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
     repeatTab.setClosable(false);
     var tableTab = new Tab("Table / Columns", tableEditor);
     tableTab.setClosable(false);
+    var problemsTab = new Tab("Problems", diagnosticsPane);
+    problemsTab.setClosable(false);
     var structureTab = new Tab("Structure", referenceEditor);
     structureTab.setClosable(false);
     var bindings =
         new TitledPane(
             "Bindings",
             new TabPane(
-                directBindingTab, computedTab, repeatTab, tableTab, structureTab, discoveryTab));
+                directBindingTab,
+                computedTab,
+                repeatTab,
+                tableTab,
+                structureTab,
+                problemsTab,
+                discoveryTab));
     bindings.setExpanded(false);
     center.setBottom(new VBox(properties, bindings));
     output.setEditable(false);
@@ -478,6 +494,7 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
         .report(
             new HostServices.Diagnostic(
                 "Designer", HostServices.Severity.ERROR, String.valueOf(error), Optional.empty()));
+    if (draft != null && diagnosticsPane != null) validationUnavailable(error);
     status.setText("Designer: " + error.getMessage());
     log(error.toString());
   }
@@ -518,6 +535,7 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
               }
             }
             draft = value;
+            publishDiagnostics("Source checked; target validation outdated", java.util.List.of());
             bindingEditor.load(value.text(), value.writable());
             computedEditor.load(value.text(), value.writable());
             repeatEditor.load(value.text(), value.writable());
@@ -544,6 +562,7 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
       var hit = kit.editor().getSelection().getHitItem();
       String selectedId = hit == null ? null : hit.getFxId();
       draft = value;
+      publishDiagnostics("Source checked; target validation outdated", java.util.List.of());
       bindingEditor.load(value.text(), value.writable());
       computedEditor.load(value.text(), value.writable());
       repeatEditor.load(value.text(), value.writable());
@@ -614,6 +633,11 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
       report(error);
     } finally {
       loading = false;
+      if (pendingSourceOffset != null) {
+        int offset = pendingSourceOffset;
+        pendingSourceOffset = null;
+        showSource(offset);
+      }
       if (value.text().equals(pendingReferenceValidation)) {
         pendingReferenceValidation = null;
         Platform.runLater(() -> validateBindings(null, false));
@@ -700,6 +724,9 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
 
   private void invalidateBindings(String message) {
     bindingRequest++;
+    host.diagnostics().clear(diagnosticsOwner);
+    if (diagnosticsPane != null) diagnosticsPane.show(java.util.List.of(), message);
+    diagnosticsRevision = -1;
     validatedSource = null;
     validatingSource = null;
     validationPreview = false;
@@ -709,6 +736,66 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
     tableEditor.invalidateDiscovery();
   }
 
+  private void publishDiagnostics(String context, java.util.List<HostServices.Diagnostic> target) {
+    if (closed || draft == null) return;
+    var all = new java.util.LinkedHashSet<>(FxmlDiagnostics.local(draft));
+    all.addAll(target);
+    var diagnostics = java.util.List.copyOf(all);
+    diagnosticsRevision = draft.revision();
+    String label = context + " · draft revision " + draft.revision();
+    diagnosticsPane.show(diagnostics, label);
+    host.diagnostics().replace(diagnosticsOwner, draft, label, diagnostics);
+  }
+
+  private void validationUnavailable(Throwable error) {
+    publishDiagnostics(
+        "Validation unavailable; results are not a clean bill of health",
+        java.util.List.of(
+            new HostServices.Diagnostic(
+                "Designer",
+                HostServices.Severity.ERROR,
+                String.valueOf(error.getMessage()),
+                Optional.of(new HostServices.Location(draft.document(), 0)))));
+  }
+
+  private void navigateDiagnostic(HostServices.Diagnostic problem) {
+    long revision = diagnosticsRevision;
+    withDraft(
+        () -> {
+          if (revision != draft.revision()) {
+            publishDiagnostics(
+                "Document changed; validate again before navigating", java.util.List.of());
+            return;
+          }
+          problem
+              .location()
+              .ifPresent(
+                  location -> {
+                    if (location.document().equals(draft.document())) showSource(location.offset());
+                    else
+                      host.navigation()
+                          .openSource(location)
+                          .exceptionally(
+                              error -> {
+                                fx(() -> report(error));
+                                return null;
+                              });
+                  });
+        });
+  }
+
+  /** Select authoritative FXML source, preserving the host-owned draft and undo history. */
+  public void showSource(int offset) {
+    if (closed) return;
+    if (draft == null) {
+      pendingSourceOffset = offset;
+      return;
+    }
+    sourceSplit.getItems().setAll(source);
+    source.positionCaret(Math.min(Math.max(0, offset), source.getLength()));
+    source.requestFocus();
+  }
+
   private void editStructure(ReferenceEditor.Intent intent) {
     withDraft(
         () -> {
@@ -796,6 +883,7 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
           var captured = draft;
           validatingSource = captured.text();
           validationPreview |= preview;
+          publishDiagnostics("Validating target types…", java.util.List.of());
           status.setText("Validating binding types in target runtime…");
           bindingWorkflow
               .bindingDetails(
@@ -820,12 +908,18 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
                             boolean resumePreview = validationPreview;
                             validationPreview = false;
                             if (error != null) {
+                              validationUnavailable(error);
                               status.setText(
                                   "Binding validation unavailable: " + error.getMessage());
                               return;
                             }
                             validatedSource = captured.text();
                             bindingProblems = metadata.problems();
+                            publishDiagnostics(
+                                last
+                                    ? "Explicit retained build (outdated)"
+                                    : "Current successful build",
+                                FxmlDiagnostics.target(captured, metadata.problems()));
                             bindingEditor.metadata(
                                 metadata,
                                 values,
@@ -888,6 +982,7 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
                             boolean resumePreview = validationPreview;
                             validationPreview = false;
                             if (error != null) {
+                              validationUnavailable(error);
                               bindingBrowser.invalidate(
                                   "Discovery unavailable: "
                                       + error.getMessage()
@@ -896,6 +991,11 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
                             }
                             validatedSource = captured.text();
                             bindingProblems = metadata.problems();
+                            publishDiagnostics(
+                                last
+                                    ? "Explicit retained build (outdated)"
+                                    : "Current successful build",
+                                FxmlDiagnostics.target(captured, metadata.problems()));
                             bindingBrowser.show(
                                 metadata,
                                 (last
@@ -1278,6 +1378,7 @@ public final class DesignerPane extends BorderPane implements AutoCloseable {
   public void close() {
     if (closed) return;
     closed = true;
+    host.diagnostics().clear(diagnosticsOwner);
     try {
       changes.close();
       saves.close();

designer-kit-ui/src/main/java/de/neitzel/fxdesigner/kit/DiagnosticsPane.java

@@ -0,0 +1,61 @@
+package de.neitzel.fxdesigner.kit;
+
+import de.neitzel.fxdesigner.host.HostServices.Diagnostic;
+import java.util.List;
+import java.util.function.Consumer;
+import javafx.scene.control.*;
+import javafx.scene.input.KeyCode;
+import javafx.scene.layout.VBox;
+
+/** One shared, navigable diagnostic list for both hosts. */
+final class DiagnosticsPane extends VBox {
+  private final ListView<Diagnostic> problems = new ListView<>();
+  private final Label state = new Label("Target validation not run");
+
+  DiagnosticsPane(Runnable validate, Consumer<Diagnostic> navigate) {
+    super(5);
+    problems.setId("diagnostics-list");
+    problems.setPrefHeight(110);
+    state.setId("diagnostics-state");
+    state.setWrapText(true);
+    problems.setCellFactory(
+        v ->
+            new ListCell<>() {
+              @Override
+              protected void updateItem(Diagnostic d, boolean empty) {
+                super.updateItem(d, empty);
+                setText(
+                    empty || d == null
+                        ? null
+                        : d.severity() + " · " + d.operation() + " · " + d.message());
+              }
+            });
+    Runnable open =
+        () -> {
+          var d = problems.getSelectionModel().getSelectedItem();
+          if (d != null) navigate.accept(d);
+        };
+    problems.setOnMouseClicked(
+        e -> {
+          if (e.getClickCount() == 2) open.run();
+        });
+    problems.setOnKeyPressed(
+        e -> {
+          if (e.getCode() == KeyCode.ENTER) {
+            open.run();
+            e.consume();
+          }
+        });
+    var check = new Button("Validate View");
+    check.setOnAction(e -> validate.run());
+    var go = new Button("Go to FXML");
+    go.setOnAction(e -> open.run());
+    go.disableProperty().bind(problems.getSelectionModel().selectedItemProperty().isNull());
+    getChildren().addAll(new javafx.scene.layout.HBox(6, check, go), state, problems);
+  }
+
+  void show(List<Diagnostic> diagnostics, String context) {
+    problems.getItems().setAll(diagnostics);
+    state.setText(context + " · " + diagnostics.size() + " diagnostics");
+  }
+}

designer-kit-ui/src/main/java/de/neitzel/fxdesigner/kit/FxmlDiagnostics.java

@@ -0,0 +1,92 @@
+package de.neitzel.fxdesigner.kit;
+
+import de.neitzel.fxdesigner.contracts.DocumentSnapshot;
+import de.neitzel.fxdesigner.host.HostServices.*;
+import de.neitzel.fxdesigner.protocol.BindingMetadata.Problem;
+import java.util.*;
+import org.w3c.dom.Element;
+import org.xml.sax.SAXParseException;
+
+/** Maps shared validation evidence to the authoritative FXML, never to the Kit projection. */
+final class FxmlDiagnostics {
+  static List<Diagnostic> local(DocumentSnapshot source) {
+    var messages = new LinkedHashSet<String>();
+    int offset = 0;
+    try {
+      var xml = new BindingDocument(source.text());
+      offset = xml.source.tags.getFirst().start();
+      messages.addAll(xml.errors());
+      messages.addAll(new TableDocument(source.text()).errors());
+      messages.addAll(new ReferenceDocument(source.text()).referenceErrors());
+    } catch (Exception e) {
+      if (e instanceof SAXParseException parse)
+        offset = offset(source.text(), parse.getLineNumber() - 1, parse.getColumnNumber() - 1);
+      messages.add(String.valueOf(e.getMessage()));
+    }
+    int origin = offset;
+    return messages.stream().map(m -> diagnostic(source, "FXML", "ERROR", m, origin)).toList();
+  }
+
+  static List<Diagnostic> target(DocumentSnapshot source, List<Problem> problems) {
+    var result = new LinkedHashSet<Diagnostic>();
+    try {
+      var xml = new BindingDocument(source.text());
+      for (var p : problems) {
+        var matches = new ArrayList<Integer>();
+        for (int i = 0; i < xml.elements.size(); i++) {
+          var e = xml.elements.get(i);
+          if ((xml.named(e, "DirectBinding") || xml.named(e, "ComputedBinding"))
+              && property(e, "control").equals(p.control())
+              && property(e, "property").equals(p.property())) matches.add(i);
+          else if (xml.named(e, "Repeat")
+              && p.property().equals("children")
+              && property(e, "pane").equals(p.control())) matches.add(i);
+        }
+        if (matches.isEmpty()) {
+          for (int i = 0; i < xml.elements.size(); i++) {
+            var e = xml.elements.get(i);
+            if ((!p.control().isEmpty()
+                    && e.getAttributeNS(BindingDocument.FX, "id").equals(p.control()))
+                || xml.named(e, "Table") && p.control().equals("Table #" + i)) matches.add(i);
+          }
+        }
+        // Unknown or aggregate origins remain at the document root, not a guessed Java/Row
+        // location.
+        if (matches.isEmpty()) matches.add(0);
+        for (int i : matches)
+          result.add(
+              diagnostic(
+                  source, "Bindings", p.severity(), p.message(), xml.source.tags.get(i).start()));
+      }
+    } catch (Exception e) {
+      return local(source);
+    }
+    return List.copyOf(result);
+  }
+
+  private static String property(Element e, String name) {
+    if (e.hasAttribute(name)) return e.getAttribute(name);
+    for (var n = e.getFirstChild(); n != null; n = n.getNextSibling())
+      if (n instanceof Element child && child.getTagName().equals(name))
+        return child.getTextContent().trim();
+    return "";
+  }
+
+  private static Diagnostic diagnostic(
+      DocumentSnapshot source, String operation, String severity, String message, int offset) {
+    return new Diagnostic(
+        operation,
+        Severity.valueOf(severity),
+        message,
+        Optional.of(new Location(source.document(), offset)));
+  }
+
+  static int offset(String text, int line, int column) {
+    int at = 0;
+    for (int n = 0; n < line && at < text.length(); n++) {
+      int next = text.indexOf('\n', at);
+      at = next < 0 ? text.length() : next + 1;
+    }
+    return Math.min(text.length(), at + Math.max(0, column));
+  }
+}

designer-kit-ui/src/test/java/de/neitzel/fxdesigner/kit/FxmlDiagnosticsTest.java

@@ -0,0 +1,83 @@
+package de.neitzel.fxdesigner.kit;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import de.neitzel.fxdesigner.contracts.DocumentSnapshot;
+import de.neitzel.fxdesigner.protocol.BindingMetadata.Problem;
+import java.net.URI;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class FxmlDiagnosticsTest {
+  private DocumentSnapshot source(String xml) {
+    return new DocumentSnapshot(URI.create("file:/View.fxml"), 3, xml, true, true);
+  }
+
+  private static final String XML =
+      "<?import de.neitzel.fx.view.*?><VBox xmlns:fx='http://javafx.com/fxml/1'>\n"
+          + "<fx:define><BindingList><!-- untouched --><DirectBinding control='field'"
+          + " property='text' path='missing' direction='view'/><Repeat pane='rows'"
+          + " collection='items' component='app.Row'/></BindingList></fx:define>\n"
+          + "<Label fx:id='field'/><VBox fx:id='rows'/><Table fx:id='table' collection='items'"
+          + " row='app.Row'><columns><Column header='N'"
+          + " attribute='name'/></columns></Table></VBox>";
+
+  @Test
+  void locatesBindingsRepeatAndTableWithoutProjectionIdentities() {
+    var d = source(XML);
+    var result =
+        FxmlDiagnostics.target(
+            d,
+            List.of(
+                new Problem("field", "text", "ERROR", "bad path"),
+                new Problem("rows", "children", "WARNING", "unknown"),
+                new Problem("table", "columns", "ERROR", "bad column")));
+    assertEquals(
+        List.of(XML.indexOf("<DirectBinding"), XML.indexOf("<Repeat"), XML.indexOf("<Table")),
+        result.stream().map(p -> p.location().orElseThrow().offset()).toList());
+    assertTrue(
+        result.stream().allMatch(p -> p.location().orElseThrow().document().equals(d.document())));
+  }
+
+  @Test
+  void ambiguousTargetsIdentifyEveryDeclarationAndDeduplicateEvidence() {
+    String xml =
+        XML.replace(
+            "<!-- untouched -->",
+            "<ComputedBinding control='field' property='text' method='#value'/>");
+    var p = new Problem("field", "text", "ERROR", "duplicate");
+    var result = FxmlDiagnostics.target(source(xml), List.of(p, p));
+    assertEquals(2, result.size());
+    assertEquals(
+        xml.indexOf("<ComputedBinding"), result.getFirst().location().orElseThrow().offset());
+  }
+
+  @Test
+  void unknownOriginsFallBackToRootAndNestedTargetsAreLocated() {
+    String xml =
+        XML.replace(
+            "control='field' property='text' path='missing' direction='view'/>",
+            "path='missing'"
+                + " direction='view'><control>field</control><property>text</property></DirectBinding>");
+    var result =
+        FxmlDiagnostics.target(
+            source(xml),
+            List.of(
+                new Problem("field", "text", "ERROR", "bad"),
+                new Problem("", "", "WARNING", "context unavailable")));
+    assertEquals(
+        xml.indexOf("<DirectBinding"), result.getFirst().location().orElseThrow().offset());
+    assertEquals(xml.indexOf("<VBox"), result.getLast().location().orElseThrow().offset());
+  }
+
+  @Test
+  void structuralErrorsAndMalformedXmlRemainNavigable() {
+    assertFalse(
+        FxmlDiagnostics.local(source(XML.replace("direction='view'", "direction='wrong'")))
+            .isEmpty());
+    var malformed = FxmlDiagnostics.local(source("<VBox>\n<Label>\n</VBox>"));
+    assertEquals(1, malformed.size());
+    assertTrue(malformed.getFirst().location().orElseThrow().offset() > 0);
+    assertTrue(FxmlDiagnostics.local(source(XML)).isEmpty());
+  }
+}

designer-kit-ui/src/test/java/de/neitzel/fxdesigner/kit/ProjectionHostChecks.java

@@ -691,6 +691,75 @@ public final class ProjectionHostChecks {
         });
   }
 
+  @SuppressWarnings("unchecked")
+  private static java.util.List<de.neitzel.fxdesigner.host.HostServices.Diagnostic> diagnostics(
+      DesignerPane pane) throws Exception {
+    return fx(
+        () ->
+            java.util.List.copyOf(
+                ((ListView<de.neitzel.fxdesigner.host.HostServices.Diagnostic>)
+                        pane.lookup("#diagnostics-list"))
+                    .getItems()));
+  }
+
+  private static void diagnosticsEdits(DesignerPane pane, DocumentSession document, String full)
+      throws Exception {
+    String invalid = full.replace("path=\"rank\"", "path=\"diagnosticMissing\"");
+    set(document, invalid);
+    await(() -> fx(() -> source(pane).getText().equals(invalid)));
+    bindingTab(pane, "Problems");
+    click(pane, "Validate View");
+    await(
+        () -> diagnostics(pane).stream().anyMatch(d -> d.message().contains("diagnosticMissing")));
+    var problem =
+        diagnostics(pane).stream()
+            .filter(d -> d.message().contains("diagnosticMissing"))
+            .findFirst()
+            .orElseThrow();
+    int offset = problem.location().orElseThrow().offset();
+    check(
+        invalid.substring(offset).startsWith("<DirectBinding"),
+        "Diagnostic did not locate authoritative binding declaration");
+    fx(
+        () -> {
+          ((ListView<de.neitzel.fxdesigner.host.HostServices.Diagnostic>)
+                  pane.lookup("#diagnostics-list"))
+              .getSelectionModel()
+              .select(problem);
+          return null;
+        });
+    click(pane, "Go to FXML");
+    await(() -> fx(() -> source(pane).getCaretPosition() == offset));
+    check(documentText(document).equals(invalid), "Diagnostic navigation mutated source");
+    set(document, full);
+    await(() -> fx(() -> source(pane).getText().equals(full)));
+    await(
+        () -> diagnostics(pane).stream().noneMatch(d -> d.message().contains("diagnosticMissing")));
+    repeatHistory(pane, document, invalid, full);
+    bindingTab(pane, "Problems");
+    click(pane, "Validate View");
+    await(
+        () ->
+            fx(
+                () ->
+                    ((Label) pane.lookup("#diagnostics-state"))
+                        .getText()
+                        .startsWith("Current successful build")));
+    check(
+        diagnostics(pane).stream()
+            .noneMatch(d -> d.severity() == de.neitzel.fxdesigner.host.HostServices.Severity.ERROR),
+        "Corrected source retained error diagnostics");
+    set(document, "<VBox>\n<Label>\n</VBox>");
+    await(() -> diagnostics(pane).stream().anyMatch(d -> d.operation().equals("FXML")));
+    set(document, full);
+    await(() -> fx(() -> source(pane).getText().equals(full)));
+    await(() -> diagnostics(pane).isEmpty());
+    click(pane, "Split");
+    System.out.println(
+        "PASS shared diagnostics: authoritative binding location, source navigation, stale"
+            + " withdrawal, correction, exact undo/redo and malformed FXML recovery");
+  }
+
   private static void structureEdits(DesignerPane pane, DocumentSession document, String full)
       throws Exception {
     String base =
@@ -1708,6 +1777,7 @@ public final class ProjectionHostChecks {
     tableDiscovery(pane, document, full);
     tableEdits(pane, document, full);
     structureEdits(pane, document, full);
+    diagnosticsEdits(pane, document, full);
     document
         .save(document.snapshot().toCompletableFuture().get().revision())
         .toCompletableFuture()