[code-style] IJPL-179136 include the just-computed settings object in CodeStyleSettingsChangeEvent

CodeStyleSettingsChangeEvent sent to notify listeners that a value has just finished computing now includes the just-computed CodeStyleSettings object.

Listeners should use this object instead of fetching settings again via `CodeStyle.getSettings(project, vfile)` or similar file-specific calls.

GitOrigin-RevId: 57705c6faf8190858fe3dc962bb498935ae1c1e8

platform/code-style-api/api-dump-experimental.txt

@@ -6,6 +6,8 @@ f:com.intellij.formatting.Indent$Type
 - *sf:OUTDENT_SPACES:com.intellij.formatting.Indent$Type
 c:com.intellij.openapi.editor.EditorModificationUtilEx
 - *s:calcAfterLineEnd(com.intellij.openapi.editor.Editor,I,com.intellij.openapi.editor.LogicalPosition,com.intellij.openapi.editor.VisualPosition):I
+f:com.intellij.psi.codeStyle.CodeStyleSettingsChangeEvent
+- *:getSettings():com.intellij.psi.codeStyle.CodeStyleSettings
 *:com.intellij.psi.codeStyle.CommentStyleSettings
 - a:isBlockCommentIncludesSpace():Z
 - a:isLineCommentFollowedWithSpace():Z

platform/code-style-api/src/com/intellij/psi/codeStyle/CodeStyleSettingsChangeEvent.java

@@ -13,11 +13,18 @@ import org.jetbrains.annotations.Nullable;
 public final class CodeStyleSettingsChangeEvent {
   private final @NotNull  Project     myProject;
   private final @Nullable VirtualFile myFile;
+  private final @Nullable CodeStyleSettings mySettings;
 
   @ApiStatus.Internal
   public CodeStyleSettingsChangeEvent(@NotNull Project project, @Nullable VirtualFile file) {
+    this(project, file, null);
+  }
+
+  @ApiStatus.Internal
+  public CodeStyleSettingsChangeEvent(@NotNull Project project, @Nullable VirtualFile file, @Nullable CodeStyleSettings settings) {
     myFile = file;
     myProject = project;
+    mySettings = settings;
   }
 
   /**
@@ -33,4 +40,19 @@ public final class CodeStyleSettingsChangeEvent {
   public @NotNull Project getProject() {
     return myProject;
   }
+
+  /**
+   * Non-null value if the reason for the event is that async computation of code style settings just finished.
+   * Non-null value also implies {@link #getVirtualFile()} is not null.
+   * <p>
+   * If non-null, the value should be used directly when handling the event instead of
+   * {@link com.intellij.application.options.CodeStyle#getSettings(Project, VirtualFile)},
+   * or similar file-specific calls.
+   *
+   * @return The current code style settings for {@link #getVirtualFile()}
+   */
+  @ApiStatus.Experimental
+  public @Nullable CodeStyleSettings getSettings() {
+    return mySettings;
+  }
 }

platform/code-style-api/src/com/intellij/psi/codeStyle/CodeStyleSettingsManager.java

@@ -386,12 +386,17 @@ public class CodeStyleSettingsManager implements PersistentStateComponentWithMod
     getMessageBus().connect().subscribe(CodeStyleSettingsListener.TOPIC, listener);
   }
 
-  public void fireCodeStyleSettingsChanged(@NotNull VirtualFile file) {
+  @ApiStatus.Internal
+  public void fireCodeStyleSettingsChanged(@NotNull VirtualFile file, @Nullable CodeStyleSettings settings) {
     if (getProject() != null) {
-      fireCodeStyleSettingsChanged(new CodeStyleSettingsChangeEvent(getProject(), file));
+      fireCodeStyleSettingsChanged(new CodeStyleSettingsChangeEvent(getProject(), file, settings));
     }
   }
 
+  public void fireCodeStyleSettingsChanged(@NotNull VirtualFile file) {
+    fireCodeStyleSettingsChanged(file, null);
+  }
+
   public void fireCodeStyleSettingsChanged() {
     if (getProject() != null) {
       fireCodeStyleSettingsChanged(new CodeStyleSettingsChangeEvent(getProject(), null));

platform/code-style-impl/src/com/intellij/application/options/codeStyle/cache/CodeStyleCachedValueProvider.kt

@@ -283,7 +283,8 @@ internal class CodeStyleCachedValueProvider(val fileSupplier: Supplier<VirtualFi
          */
         if (!TooFrequentCodeStyleComputationWatcher.getInstance(project).isTooHighEvictionRateDetected()
             && !Registry.`is`("disable.codeStyleSettingsChanged.events.on.settings.cached")) {
-          settingsManager.fireCodeStyleSettingsChanged(file)
+          val eventSettings = if (Registry.`is`("code.style.cache.change.events.include.settings")) currentResult else null
+          settingsManager.fireCodeStyleSettingsChanged(file, eventSettings)
         }
       }
       computation.reset()

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

@@ -118,6 +118,9 @@
                  description="Maximum size of the code style settings cache (>= 1)."
                  key="code.style.cache.maximum.size"
                  restartRequired="true" />
+    <registryKey defaultValue="true"
+                 description="Include code style settings in change events if the reason is computation of the settings has just finished."
+                 key="code.style.cache.change.events.include.settings" />"
     <!-- endregion -->
 
     <projectService serviceInterface="com.intellij.util.indexing.IndexableFilesIndex"