Initial support for icon description tooltips (IDEA-237109)

GitOrigin-RevId: 137eb5c9b12d890b4f446b106523207f1b54e96a

java/java-impl/src/com/intellij/psi/impl/JavaDirectoryIconProvider.java

@@ -19,6 +19,7 @@ import com.intellij.psi.PsiDirectory;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.impl.file.PsiDirectoryFactory;
 import com.intellij.ui.IconManager;
+import com.intellij.ui.IconWithToolTip;
 import com.intellij.util.PlatformIcons;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -53,7 +54,7 @@ final class JavaDirectoryIconProvider extends IconProvider implements DumbAware
         symbolIcon = AllIcons.Nodes.Module;
       }
       else if (isValidPackage(psiDirectory)) {
-        symbolIcon = PlatformIcons.PACKAGE_ICON;
+        symbolIcon = IconWithToolTip.tooltipOnlyIfComposite(PlatformIcons.PACKAGE_ICON);
       }
       else if (!Registry.is("ide.hide.excluded.files") && ProjectRootManager.getInstance(project).getFileIndex().isExcluded(vFile)) {
         symbolIcon = AllIcons.Modules.ExcludeRoot;

java/java-psi-impl/src/com/intellij/psi/impl/ElementPresentationUtil.java

@@ -12,6 +12,7 @@ import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.*;
 import com.intellij.psi.util.*;
 import com.intellij.ui.IconManager;
+import com.intellij.ui.IconWithToolTip;
 import com.intellij.ui.icons.RowIcon;
 import com.intellij.util.BitUtil;
 import com.intellij.util.PlatformIcons;
@@ -142,7 +143,7 @@ public final class ElementPresentationUtil implements PlatformIcons {
 
   private static final TIntObjectHashMap<Icon> BASE_ICON = new TIntObjectHashMap<>(20);
   static {
-    BASE_ICON.put(CLASS_KIND_CLASS, CLASS_ICON);
+    BASE_ICON.put(CLASS_KIND_CLASS, IconWithToolTip.tooltipOnlyIfComposite(CLASS_ICON));
     BASE_ICON.put(CLASS_KIND_CLASS | FLAGS_ABSTRACT, ABSTRACT_CLASS_ICON);
     BASE_ICON.put(CLASS_KIND_ANNOTATION, ANNOTATION_TYPE_ICON);
     BASE_ICON.put(CLASS_KIND_ANNOTATION | FLAGS_ABSTRACT, ANNOTATION_TYPE_ICON);
@@ -154,9 +155,9 @@ public final class ElementPresentationUtil implements PlatformIcons {
     BASE_ICON.put(CLASS_KIND_ENUM | FLAGS_ABSTRACT, ENUM_ICON);
     BASE_ICON.put(CLASS_KIND_EXCEPTION, EXCEPTION_CLASS_ICON);
     BASE_ICON.put(CLASS_KIND_EXCEPTION | FLAGS_ABSTRACT, AllIcons.Nodes.AbstractException);
-    BASE_ICON.put(CLASS_KIND_INTERFACE, INTERFACE_ICON);
-    BASE_ICON.put(CLASS_KIND_INTERFACE | FLAGS_ABSTRACT, INTERFACE_ICON);
-    BASE_ICON.put(CLASS_KIND_JUNIT_TEST, CLASS_ICON);
+    BASE_ICON.put(CLASS_KIND_INTERFACE, IconWithToolTip.tooltipOnlyIfComposite(INTERFACE_ICON));
+    BASE_ICON.put(CLASS_KIND_INTERFACE | FLAGS_ABSTRACT, IconWithToolTip.tooltipOnlyIfComposite(INTERFACE_ICON));
+    BASE_ICON.put(CLASS_KIND_JUNIT_TEST, IconWithToolTip.tooltipOnlyIfComposite(CLASS_ICON));
     BASE_ICON.put(CLASS_KIND_JUNIT_TEST | FLAGS_ABSTRACT, ABSTRACT_CLASS_ICON);
     BASE_ICON.put(CLASS_KIND_RECORD, RECORD_ICON);
     BASE_ICON.put(CLASS_KIND_RUNNABLE, CLASS_ICON);

platform/core-impl/src/com/intellij/psi/impl/file/PsiDirectoryImpl.java

@@ -28,6 +28,7 @@ import com.intellij.psi.search.PsiElementProcessor;
 import com.intellij.psi.search.PsiFileSystemItemProcessor;
 import com.intellij.psi.util.PsiUtilCore;
 import com.intellij.testFramework.LightVirtualFile;
+import com.intellij.ui.IconWithToolTip;
 import com.intellij.util.ArrayUtilRt;
 import com.intellij.util.IncorrectOperationException;
 import com.intellij.util.PlatformIcons;
@@ -527,7 +528,7 @@ public class PsiDirectoryImpl extends PsiElementBase implements PsiDirectory, Qu
 
   @Override
   protected Icon getElementIcon(final int flags) {
-    return PlatformIcons.FOLDER_ICON;
+    return IconWithToolTip.tooltipOnlyIfComposite(PlatformIcons.FOLDER_ICON);
   }
 
   @Override

platform/core-ui/src/ui/CoreIconManager.java

@@ -1,9 +1,15 @@
 // Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.ui;
 
+import com.intellij.AbstractBundle;
+import com.intellij.DynamicBundle;
 import com.intellij.ide.IconLayerProvider;
+import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.util.IconLoader;
 import com.intellij.openapi.util.Iconable;
+import com.intellij.openapi.util.Ref;
+import com.intellij.openapi.util.registry.Registry;
+import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.util.BitUtil;
 import com.intellij.util.IconUtil;
 import com.intellij.util.SmartList;
@@ -14,16 +20,20 @@ import org.jetbrains.annotations.NotNull;
 import javax.swing.*;
 import java.awt.*;
 import java.util.List;
+import java.util.ResourceBundle;
 import java.util.function.Function;
+import java.util.function.Supplier;
 
 public final class CoreIconManager implements IconManager {
   private static final List<IconLayer> ourIconLayers  = ContainerUtil.createLockFreeCopyOnWriteList();
   private static final int FLAGS_LOCKED = 0x800;
+  private static final Logger LOG = Logger.getInstance(CoreIconManager.class);
 
   @NotNull
   @Override
   public Icon getIcon(@NotNull String path, @NotNull Class aClass) {
-    return IconLoader.getIcon(path, aClass);
+    Icon icon = IconLoader.getIcon(path, aClass);
+    return IconWithToolTip.create(icon, new IconDescriptionLoader(path));
   }
 
   @NotNull
@@ -125,4 +135,42 @@ public final class CoreIconManager implements IconManager {
       this.icon = icon;
     }
   }
+
+  private static class IconDescriptionLoader implements Supplier<String> {
+    private final String myPath;
+    private String myResult;
+    private boolean myCalculated;
+
+    private IconDescriptionLoader(String path) {
+      myPath = path;
+    }
+
+    @Override
+    public String get() {
+      if (!myCalculated) {
+        myResult = findIconDescription();
+        myCalculated = true;
+      }
+      return myResult;
+    }
+
+    private String findIconDescription() {
+      String basePath = StringUtil.trimStart(StringUtil.trimEnd(myPath, ".svg"), "/");
+      String key = "icon." + basePath.replace('/', '.') + ".tooltip";
+      Ref<String> result = new Ref<>();
+      IconDescriptionBundleEP.EP_NAME.processWithPluginDescriptor((ep, descriptor) -> {
+        ClassLoader classLoader = descriptor == null ? null : descriptor.getPluginClassLoader();
+        if (classLoader == null) classLoader = getClass().getClassLoader();
+        ResourceBundle bundle = DynamicBundle.INSTANCE.getResourceBundle(ep.qualifiedName, classLoader);
+        String description = AbstractBundle.messageOrNull(bundle, key);
+        if (description != null) {
+          result.set(description);
+        }
+      });
+      if (result.get() == null && Registry.is("ide.icon.tooltips.trace.missing")) {
+        LOG.info("Icon tooltip requested but not found for " + myPath);
+      }
+      return result.get();
+    }
+  }
 }

platform/core-ui/src/ui/IconDescriptionBundleEP.java

@@ -0,0 +1,12 @@
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.ui;
+
+import com.intellij.openapi.extensions.ExtensionPointName;
+import com.intellij.util.xmlb.annotations.Attribute;
+
+public class IconDescriptionBundleEP {
+  public static final ExtensionPointName<IconDescriptionBundleEP> EP_NAME = ExtensionPointName.create("com.intellij.iconDescriptionBundle");
+
+  @Attribute("qualifiedName")
+  public String qualifiedName;
+}

platform/core-ui/src/ui/IconWithToolTip.java

@@ -0,0 +1,29 @@
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.ui;
+
+import org.jetbrains.annotations.Nullable;
+
+import javax.swing.*;
+import java.util.function.Supplier;
+
+/**
+ * Icon which supports providing a tooltip.
+ */
+public interface IconWithToolTip extends Icon {
+  /**
+   * Returns the tooltip for the icon.
+   * @param composite if true, this tooltip will be combined with other tooltips (from other layers of a layered icon or parts of a row icon).
+   *                  For some icons, it only makes sense to show a tooltip if the icon is composite.
+   * @return
+   */
+  @Nullable
+  String getToolTip(boolean composite);
+
+  static IconWithToolTip create(Icon icon, Supplier<String> tooltip) {
+    return new IconWrapperWithToolTip(icon, tooltip);
+  }
+
+  static IconWithToolTip tooltipOnlyIfComposite(Icon icon) {
+    return new IconWrapperWithToolTipComposite(icon);
+  }
+}

platform/core-ui/src/ui/IconWrapperWithToolTip.java

@@ -0,0 +1,49 @@
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.ui;
+
+import org.jetbrains.annotations.NotNull;
+
+import javax.swing.*;
+import java.awt.*;
+import java.util.function.Supplier;
+
+public class IconWrapperWithToolTip implements IconWithToolTip, RetrievableIcon {
+  private final Icon myIcon;
+  private final Supplier<String> myToolTip;
+
+  public IconWrapperWithToolTip(Icon icon, Supplier<String> toolTip) {
+    myIcon = icon;
+    myToolTip = toolTip;
+  }
+
+  @Override
+  public void paintIcon(Component c, Graphics g, int x, int y) {
+    myIcon.paintIcon(c, g, x, y);
+  }
+
+  @Override
+  public int getIconWidth() {
+    return myIcon.getIconWidth();
+  }
+
+  @Override
+  public int getIconHeight() {
+    return myIcon.getIconHeight();
+  }
+
+  @Override
+  public String getToolTip(boolean composite) {
+    return myToolTip.get();
+  }
+
+  @Override
+  public String toString() {
+    return "IconWrapperWithTooltip:" + myIcon;
+  }
+
+  @Override
+  public @NotNull Icon retrieveIcon() {
+    return myIcon;
+  }
+}
+

platform/core-ui/src/ui/IconWrapperWithToolTipComposite.java

@@ -0,0 +1,47 @@
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.ui;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import javax.swing.*;
+import java.awt.*;
+
+public class IconWrapperWithToolTipComposite implements IconWithToolTip, RetrievableIcon {
+  private final Icon myIcon;
+
+  public IconWrapperWithToolTipComposite(Icon icon) {
+    myIcon = icon;
+  }
+
+  @Override
+  public @Nullable String getToolTip(boolean composite) {
+    if (!composite) return null;
+    return myIcon instanceof IconWithToolTip ? ((IconWithToolTip)myIcon).getToolTip(true) : null;
+  }
+
+  @Override
+  public void paintIcon(Component c, Graphics g, int x, int y) {
+    myIcon.paintIcon(c, g, x, y);
+  }
+
+  @Override
+  public int getIconWidth() {
+    return myIcon.getIconWidth();
+  }
+
+  @Override
+  public int getIconHeight() {
+    return myIcon.getIconHeight();
+  }
+
+  @Override
+  public @NotNull Icon retrieveIcon() {
+    return myIcon;
+  }
+
+  @Override
+  public String toString() {
+    return "IconWrapperWithTooltipComposite:" + myIcon.toString();
+  }
+}

platform/core-ui/src/ui/LayeredIcon.java

@@ -10,6 +10,7 @@ import com.intellij.util.IconUtil;
 import com.intellij.util.ui.JBCachingScalableIcon;
 import org.intellij.lang.annotations.MagicConstant;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
 import java.awt.*;
@@ -18,7 +19,7 @@ import java.util.Arrays;
 import static com.intellij.ui.scale.ScaleType.OBJ_SCALE;
 import static com.intellij.ui.scale.ScaleType.USR_SCALE;
 
-public class LayeredIcon extends JBCachingScalableIcon<LayeredIcon> implements DarkIconProvider, CompositeIcon {
+public class LayeredIcon extends JBCachingScalableIcon<LayeredIcon> implements DarkIconProvider, CompositeIcon, IconWithToolTip {
   private static final Logger LOG = Logger.getInstance("#com.intellij.ui.LayeredIcon");
   private final Icon[] myIcons;
   private Icon[] myScaledIcons;
@@ -309,4 +310,48 @@ public class LayeredIcon extends JBCachingScalableIcon<LayeredIcon> implements D
   public String toString() {
     return "Layered icon "+getIconWidth()+"x"+getIconHeight()+". myIcons=" + Arrays.asList(myIcons);
   }
+
+  @Override
+  public String getToolTip(boolean composite) {
+    return combineIconTooltips(myIcons);
+  }
+
+  @Nullable
+  static String combineIconTooltips(Icon[] icons) {
+    // If a layered icon contains only a single non-null layer and other layers are null, its tooltip is not a composite one.
+    Icon singleIcon = null;
+    for (Icon icon : icons) {
+      if (icon != null) {
+        if (singleIcon != null) {
+          return buildCompositeTooltip(icons);
+        }
+        singleIcon = icon;
+      }
+    }
+    if (singleIcon != null) {
+      return singleIcon instanceof IconWithToolTip ? ((IconWithToolTip) singleIcon).getToolTip(false) : null;
+    }
+    return null;
+  }
+
+  @Nullable
+  private static String buildCompositeTooltip(Icon[] icons) {
+    StringBuilder result = null;
+    for (int i = 0; i < icons.length; i++) {
+      // first layer is the actual object (noun), other layers are modifiers (adjectives), so put first object in last position
+      Icon icon = i == icons.length - 1 ? icons[0] : icons[i + 1];
+      if (icon instanceof IconWithToolTip) {
+        String toolTip = ((IconWithToolTip)icon).getToolTip(true);
+        if (toolTip != null) {
+          if (result == null) {
+            result = new StringBuilder(toolTip);
+          }
+          else {
+            result.append(" ").append(toolTip);
+          }
+        }
+      }
+    }
+    return result != null ? result.toString() : null;
+  }
 }

platform/core-ui/src/ui/RowIcon.java

@@ -17,7 +17,7 @@ import java.util.List;
 import static com.intellij.ui.scale.ScaleType.OBJ_SCALE;
 import static java.lang.Math.ceil;
 
-public class RowIcon extends JBCachingScalableIcon<RowIcon> implements com.intellij.ui.icons.RowIcon {
+public class RowIcon extends JBCachingScalableIcon<RowIcon> implements com.intellij.ui.icons.RowIcon, IconWithToolTip {
   private final com.intellij.ui.icons.RowIcon.Alignment myAlignment;
 
   private int myWidth;
@@ -202,4 +202,9 @@ public class RowIcon extends JBCachingScalableIcon<RowIcon> implements com.intel
   public String toString() {
     return "Row icon. myIcons=" + Arrays.asList(myIcons);
   }
+
+  @Override
+  public String getToolTip(boolean composite) {
+    return LayeredIcon.combineIconTooltips(myIcons);
+  }
 }

platform/core-ui/src/util/IconUtil.java

@@ -188,7 +188,7 @@ public class IconUtil {
     }
     FileType fileType = vFile.getFileType();
     if (vFile.isDirectory() && !(fileType instanceof DirectoryFileType)) {
-      return PlatformIcons.FOLDER_ICON;
+      return IconWithToolTip.tooltipOnlyIfComposite(PlatformIcons.FOLDER_ICON);
     }
     return fileType.getIcon();
   }

platform/lang-impl/src/com/intellij/ide/bookmarks/Bookmark.java

@@ -38,6 +38,7 @@ import com.intellij.psi.PsiFile;
 import com.intellij.psi.PsiManager;
 import com.intellij.reference.SoftReference;
 import com.intellij.ui.ColorUtil;
+import com.intellij.ui.IconWithToolTip;
 import com.intellij.ui.JBColor;
 import com.intellij.ui.RetrievableIcon;
 import com.intellij.util.IconUtil;
@@ -484,7 +485,7 @@ public final class Bookmark implements Navigatable, Comparable<Bookmark> {
     }
   }
 
-  private static class MyCheckedIcon extends JBCachingScalableIcon<MyCheckedIcon> implements RetrievableIcon {
+  private static class MyCheckedIcon extends JBCachingScalableIcon<MyCheckedIcon> implements RetrievableIcon, IconWithToolTip {
     @NotNull
     @Override
     public Icon retrieveIcon() {
@@ -515,6 +516,11 @@ public final class Bookmark implements Navigatable, Comparable<Bookmark> {
     public MyCheckedIcon copy() {
       return new MyCheckedIcon();
     }
+
+    @Override
+    public String getToolTip(boolean composite) {
+      return IdeBundle.message("tooltip.bookmarked");
+    }
   }
 
   private static boolean darkBackground() {

platform/lang-impl/src/com/intellij/ui/DeferredIconImpl.java

@@ -36,7 +36,7 @@ import java.util.Set;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Future;
 
-public final class DeferredIconImpl<T> extends JBCachingScalableIcon<DeferredIconImpl<T>> implements DeferredIcon, RetrievableIcon {
+public final class DeferredIconImpl<T> extends JBCachingScalableIcon<DeferredIconImpl<T>> implements DeferredIcon, RetrievableIcon, IconWithToolTip {
   private static final Logger LOG = Logger.getInstance(DeferredIconImpl.class);
   private static final int MIN_AUTO_UPDATE_MILLIS = 950;
   private static final RepaintScheduler ourRepaintScheduler = new RepaintScheduler();
@@ -320,6 +320,14 @@ public final class DeferredIconImpl<T> extends JBCachingScalableIcon<DeferredIco
     return myScaledDelegateIcon.getIconHeight();
   }
 
+  @Override
+  public String getToolTip(boolean composite) {
+    if (myScaledDelegateIcon instanceof IconWithToolTip) {
+      return ((IconWithToolTip) myScaledDelegateIcon).getToolTip(composite);
+    }
+    return null;
+  }
+
   public boolean isDone() {
     if (myAutoUpdatable && myDone && myLastCalcTime > 0 && System.currentTimeMillis() - myLastCalcTime > Math.max(MIN_AUTO_UPDATE_MILLIS, 10 * myLastTimeSpent)) {
       myDone = false;

platform/platform-api/resources/messages/IdeBundle.properties

@@ -2082,4 +2082,48 @@ button.convert.anyway=Convert anyway
 button.reload.anyway=Reload anyway
 dialog.title.file.0.can.t.be.reloaded=File ''{0}'' can''t be reloaded in the ''{1}'' encoding.{2}
 dialog.title.file.0.most.likely.isn.t.stored=File ''{0}'' most likely isn''t stored in the ''{1}'' encoding.{2}
-dumb.service.indexing.paused.due.to=Indexing paused due to {0}
+dumb.service.indexing.paused.due.to=Indexing paused due to {0}
+tooltip.bookmarked=bookmarked
+
+icon.fileTypes.archive.tooltip=archive file
+
+icon.modules.excludedGeneratedRoot.tooltip=excluded generated sources root
+icon.modules.excludeRoot.tooltip=excluded directory
+icon.modules.generatedFolder.tooltip=generated folder
+icon.modules.generatedSourceRoot.tooltip=generated sources root
+icon.modules.generatedTestRoot.tooltip=generated test sources root
+icon.modules.output.tooltip=output root
+icon.modules.resourcesRoot.tooltip=resources root
+icon.modules.sourceRoot.tooltip=sources root
+icon.modules.testResourcesRoot.tooltip=test resources root
+icon.modules.testRoot.tooltip=test sources root
+icon.modules.unloadedModule.tooltip=unloaded module
+
+icon.nodes.abstractClass.tooltip=abstract class
+icon.nodes.abstractException.tooltip=abstract exception
+icon.nodes.abstractMethod.tooltip=abstract method
+icon.nodes.annotationtype.tooltip=annotation type
+icon.nodes.anonymousClass.tooltip=anonymous class
+icon.nodes.c_plocal.tooltip=package-local
+icon.nodes.c_private.tooltip=private
+icon.nodes.c_protected.tooltip=protected
+icon.nodes.c_public.tooltip=public
+icon.nodes.class.tooltip=class
+icon.nodes.classInitializer.tooltip=class initializer
+icon.nodes.enum.tooltip=enum
+icon.nodes.excludedFromCompile.tooltip=excluded from compilation
+icon.nodes.field.tooltip=field
+icon.nodes.finalMark.tooltip=final
+icon.nodes.folder.tooltip=folder
+icon.nodes.ideaModule.tooltip=IntelliJ module file
+icon.nodes.interface.tooltip=interface
+icon.nodes.junitTestMark.tooltip=unit test
+icon.nodes.locked.tooltip=read-only
+icon.nodes.method.tooltip=method
+icon.nodes.Module.tooltip=module
+icon.nodes.moduleGroup.tooltip=module group
+icon.nodes.package.tooltip=package
+icon.nodes.ppJdk.tooltip=JDK
+icon.nodes.ppLib.tooltip=external library
+icon.nodes.runnableMark.tooltip=runnable
+icon.nodes.staticMark.tooltip=static

platform/platform-api/src/com/intellij/ui/SimpleColoredComponent.java

@@ -8,6 +8,7 @@ import com.intellij.openapi.ui.GraphicsConfig;
 import com.intellij.openapi.util.Comparing;
 import com.intellij.openapi.util.NlsContexts;
 import com.intellij.openapi.util.SystemInfo;
+import com.intellij.openapi.util.registry.Registry;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.ui.paint.EffectPainter;
 import com.intellij.ui.scale.JBUIScale;
@@ -24,6 +25,7 @@ import javax.swing.*;
 import javax.swing.border.Border;
 import javax.swing.tree.TreeCellRenderer;
 import java.awt.*;
+import java.awt.event.MouseEvent;
 import java.awt.font.FontRenderContext;
 import java.awt.font.TextAttribute;
 import java.awt.font.TextLayout;
@@ -1078,6 +1080,17 @@ public class SimpleColoredComponent extends JComponent implements Accessible, Co
     }
   }
 
+  @Override
+  public String getToolTipText(MouseEvent event) {
+    if (myIcon instanceof IconWithToolTip && findFragmentAt(event.getX()) == FRAGMENT_ICON && Registry.is("ide.icon.tooltips")) {
+      String iconToolTip = ((IconWithToolTip)myIcon).getToolTip(false);
+      if (iconToolTip != null) {
+        return iconToolTip;
+      }
+    }
+    return super.getToolTipText(event);
+  }
+
   @Override
   public AccessibleContext getAccessibleContext() {
     if (accessibleContext == null) {

platform/platform-resources/src/META-INF/LangExtensions.xml

@@ -1276,6 +1276,8 @@
     <codeInsight.lineMarkerProvider implementationClass="com.intellij.codeInsight.documentation.render.DocRenderDummyLineMarkerProvider"/>
 
     <psi.treeChangeListener implementation="com.intellij.openapi.fileEditor.impl.FileEditorPsiTreeChangeListener"/>
+
+    <iconDescriptionBundle qualifiedName="messages.IdeBundle"/>
   </extensions>
   <applicationListeners>
     <listener class="com.intellij.ide.script.IdeStartupScripts" topic="com.intellij.openapi.project.ProjectManagerListener"/>

platform/platform-resources/src/META-INF/PlatformExtensionPoints.xml

@@ -380,5 +380,6 @@
       <with attribute="implementationClass" implements="com.intellij.openapi.options.OptionEditorProvider"/>
     </extensionPoint>
 
+    <extensionPoint name="iconDescriptionBundle" beanClass="com.intellij.ui.IconDescriptionBundleEP" dynamic="true"/>
   </extensionPoints>
 </idea-plugin>

platform/platform-tests/testSrc/com/intellij/ui/IconUtilTest.java

@@ -281,7 +281,7 @@ public class IconUtilTest extends HeavyPlatformTestCase {
       UIUtil.dispatchAllInvocationEvents();
 
       List<Icon> icons = autopsyIconsFrom(icon);
-      assertOneElement(ContainerUtil.filter(icons, ic -> ic == PlatformIcons.LOCKED_ICON));
+      assertOneElement(ContainerUtil.filter(icons, ic -> ic == IconTestUtil.unwrapRetrievableIcon(PlatformIcons.LOCKED_ICON)));
     }
     finally {
       WriteCommandAction.runWriteCommandAction(getProject(),

platform/testFramework/src/com/intellij/ui/IconTestUtil.java

@@ -0,0 +1,22 @@
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.ui;
+
+import com.intellij.openapi.util.IconLoader;
+import org.jetbrains.annotations.Nullable;
+
+import javax.swing.*;
+
+public class IconTestUtil {
+  @Nullable
+  public static String getIconPath(Icon icon) {
+    icon = unwrapRetrievableIcon(icon);
+    return ((IconLoader.CachedImageIcon)icon).getOriginalPath();
+  }
+
+  public static Icon unwrapRetrievableIcon(Icon icon) {
+    while (icon instanceof RetrievableIcon) {
+      icon = ((RetrievableIcon)icon).retrieveIcon();
+    }
+    return icon;
+  }
+}

platform/util/resources/misc/registry.properties

@@ -1805,4 +1805,10 @@ indexing.progress.indicator.power.description=Indexing progress indicator speed-
 ide.background.tasks=true
 ide.background.tasks.description=Start backgroundable tasks in background without showing modal dialog with progress bar
 
+ide.icon.tooltips=true
+ide.icon.tooltips.description=Show tooltips on icons explaining their meaning
+ide.icon.tooltips.trace.missing=false
+ide.icon.tooltips.trace.missing.description=Log a message when an icon tooltip is requested but isn't available
+
+
 # TODO please use EP com.intellij.registryKey for plugin/product specific keys