[Rider] Lift some of the common UI Rider/CLionNova logic to rdclient and the platform.

(So that the Rider/CLionNova thin clients could use it)

GitOrigin-RevId: 26802752ccf2a27fd66394c44373ba573ab7a19e

platform/diff-impl/resources/META-INF/diff-impl.xml

@@ -12,6 +12,8 @@
                          implementationClass="com.intellij.openapi.vcs.ex.LineStatusMakerEscEditorHandler"
                          id="LineStatusTrackerMarkerPopup"
                          order="before hide-hints"/>
+
+    <mergeableGutterIconRendererProvider implementation="com.intellij.diff.util.DiffGutterRendererMergeableRendererProvider" />
   </extensions>
 
   <applicationListeners>

platform/diff-impl/src/com/intellij/diff/util/DiffGutterRendererMergeableRendererProvider.java

@@ -0,0 +1,41 @@
+// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.diff.util;
+
+import com.intellij.codeInsight.daemon.GutterMark;
+import com.intellij.openapi.actionSystem.AnAction;
+import com.intellij.openapi.editor.GutterMarkWrapper;
+import com.intellij.openapi.editor.ImportantNonMergeableGutterMark;
+import com.intellij.openapi.editor.MergeableGutterIconRenderer;
+import com.intellij.openapi.editor.MergeableGutterIconRendererProvider;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+@ApiStatus.Internal
+public class DiffGutterRendererMergeableRendererProvider implements MergeableGutterIconRendererProvider {
+
+  public static class DiffMergeableGutterMarkRenderer extends GutterMarkWrapper<DiffGutterRenderer> implements ImportantNonMergeableGutterMark {
+
+    protected DiffMergeableGutterMarkRenderer(DiffGutterRenderer originalMark) {
+      super(originalMark);
+    }
+
+    @Override
+    public @Nullable AnAction getClickAction() { return originalMark.getClickAction(); }
+
+    @Override
+    public boolean equals(Object obj) { return obj instanceof DiffMergeableGutterMarkRenderer && originalMark.equals(((DiffMergeableGutterMarkRenderer)obj).originalMark); }
+
+    @Override
+    public int hashCode() { return System.identityHashCode(originalMark); }
+
+    @Override
+    public int getWeight() { return 0; }
+  }
+
+  @Override
+  public @Nullable MergeableGutterIconRenderer tryGetMergeableIconRenderer(@NotNull GutterMark mark) {
+    if (!(mark instanceof DiffGutterRenderer)) return null;
+    return new DiffMergeableGutterMarkRenderer((DiffGutterRenderer)mark);
+  }
+}

platform/editor-ui-api/resources/META-INF/Editor.xml

@@ -6,6 +6,8 @@
                     dynamic="true">
       <with attribute="implementationClass" implements="com.intellij.openapi.fileTypes.SyntaxHighlighter"/>
     </extensionPoint>
+
+    <extensionPoint qualifiedName="com.intellij.mergeableGutterIconRendererProvider" interface="com.intellij.openapi.editor.MergeableGutterIconRendererProvider" dynamic="true"/>
   </extensionPoints>
   <extensions defaultExtensionNs="com.intellij">
     <applicationService serviceImplementation="com.intellij.ide.ui.UISettingsStateDefaultsProviderImpl"

platform/editor-ui-api/src/com/intellij/openapi/editor/GutterMarkWrapper.java

@@ -0,0 +1,39 @@
+// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.openapi.editor;
+
+import com.intellij.openapi.actionSystem.ActionGroup;
+import com.intellij.openapi.actionSystem.AnAction;
+import com.intellij.openapi.editor.markup.GutterDraggableObject;
+import com.intellij.openapi.editor.markup.GutterIconRenderer;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import javax.swing.*;
+
+@ApiStatus.Internal
+public abstract class GutterMarkWrapper<T extends GutterIconRenderer> extends GutterIconRenderer implements MergeableGutterIconRenderer {
+
+  protected final T originalMark;
+
+  public T getOriginalMark() { return originalMark; }
+
+  protected GutterMarkWrapper(T originalMark) {
+    this.originalMark = originalMark;
+  }
+
+  @Override public @NotNull Icon getIcon() { return originalMark.getIcon(); }
+  @Override public @Nullable String getTooltipText() { return originalMark.getTooltipText(); }
+  @Override public @NotNull Alignment getAlignment() { return Alignment.LEFT; }
+  @Override public @NotNull String getAccessibleName() { return originalMark.getAccessibleName(); }
+  @Override public @Nullable String getAccessibleTooltipText() { return originalMark.getAccessibleTooltipText(); }
+  @Override public @Nullable GutterDraggableObject getDraggableObject() { return originalMark.getDraggableObject(); }
+  @Override public @Nullable AnAction getMiddleButtonClickAction() { return originalMark.getMiddleButtonClickAction(); }
+  @Override public @Nullable ActionGroup getPopupMenuActions() { return originalMark.getPopupMenuActions(); }
+  @Override public @Nullable AnAction getRightButtonClickAction() { return originalMark.getRightButtonClickAction(); }
+  @Override public boolean isNavigateAction() { return originalMark.isNavigateAction(); }
+  @Override public boolean isDumbAware() { return originalMark.isDumbAware(); }
+  @Override public @NotNull String toString() { return originalMark.toString(); }
+
+  @Override public abstract @Nullable AnAction getClickAction();
+}

platform/editor-ui-api/src/com/intellij/openapi/editor/ImportantNonMergeableGutterMark.java

@@ -0,0 +1,13 @@
+// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.openapi.editor;
+
+import com.intellij.codeInsight.daemon.GutterMark;
+import org.jetbrains.annotations.ApiStatus;
+
+/**
+ * This interface is used in some {@link GutterMarkPreprocessor} implementors (the ones that merge the gutter marks) to
+ * mark a gutter mark as a non-participant in the merge logic.
+ */
+@ApiStatus.Internal
+public interface ImportantNonMergeableGutterMark extends GutterMark {
+}

platform/editor-ui-api/src/com/intellij/openapi/editor/MergeableGutterIconRenderer.java

@@ -0,0 +1,15 @@
+// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.openapi.editor;
+
+import com.intellij.codeInsight.daemon.GutterMark;
+import org.jetbrains.annotations.ApiStatus;
+
+@ApiStatus.Internal
+public interface MergeableGutterIconRenderer extends GutterMark, Comparable<MergeableGutterIconRenderer> {
+  int getWeight();
+
+  @Override
+  default int compareTo(MergeableGutterIconRenderer other) {
+    return -Integer.compare(this.getWeight(), other.getWeight());
+  }
+}

platform/editor-ui-api/src/com/intellij/openapi/editor/MergeableGutterIconRendererExternalWrapper.java

@@ -0,0 +1,38 @@
+// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.openapi.editor;
+
+import com.intellij.codeInsight.daemon.GutterMark;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import javax.swing.*;
+import java.util.Objects;
+
+@ApiStatus.Internal
+public abstract class MergeableGutterIconRendererExternalWrapper implements MergeableGutterIconRenderer {
+
+  private final GutterMark myOriginalMark;
+
+  public MergeableGutterIconRendererExternalWrapper(GutterMark originalMark) {
+    myOriginalMark = originalMark;
+  }
+
+  public GutterMark getOriginalMark() { return myOriginalMark; }
+
+  @Override
+  public @NotNull Icon getIcon() { return myOriginalMark.getIcon(); }
+  @Override
+  public @Nullable String getTooltipText() { return myOriginalMark.getTooltipText(); }
+
+  @Override
+  public boolean equals(@Nullable Object other) {
+    if (!(other instanceof MergeableGutterIconRendererExternalWrapper)) return false;
+    return Objects.equals(myOriginalMark, ((MergeableGutterIconRendererExternalWrapper)other).myOriginalMark);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hashCode(myOriginalMark);
+  }
+}

platform/editor-ui-api/src/com/intellij/openapi/editor/MergeableGutterIconRendererProvider.java

@@ -0,0 +1,17 @@
+// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.openapi.editor;
+
+import com.intellij.codeInsight.daemon.GutterMark;
+import com.intellij.openapi.extensions.ExtensionPointName;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+// This is a bit of a crutch inherited from the Forefathers. Please refer to RiderGutterMarksPreprocessor if you have questions.
+@ApiStatus.Internal
+public interface MergeableGutterIconRendererProvider {
+
+  ExtensionPointName<MergeableGutterIconRendererProvider> EP_NAME  = ExtensionPointName.create("com.intellij.mergeableGutterIconRendererProvider");
+
+  @Nullable MergeableGutterIconRenderer tryGetMergeableIconRenderer(@NotNull GutterMark mark);
+}