EA-122213 - assert: IndexAccessValidator.checkAccessingIndexDuringOtherIndexProcessing

java/java-indexing-impl/src/com/intellij/psi/impl/search/JavaFilesSearchScope.java

@@ -34,6 +34,6 @@ public class JavaFilesSearchScope extends GlobalSearchScope {
     if (file.isDirectory())
       return false;
     FileViewProvider viewProvider = myPsiManager.findViewProvider(file);
-    return viewProvider != null && viewProvider.getLanguages().contains(JavaLanguage.INSTANCE);
+    return viewProvider != null && viewProvider.hasLanguage(JavaLanguage.INSTANCE);
   }
 }

platform/core-api/src/com/intellij/psi/FileViewProvider.java

@@ -89,6 +89,14 @@ public interface FileViewProvider extends Cloneable, UserDataHolderEx {
   @NotNull
   Set<Language> getLanguages();
 
+  /**
+   * Check if given language is supported.
+   * Implementations may provide more effective way to check without getting all languages.
+   */
+  default boolean hasLanguage(@NotNull Language language) {
+    return getLanguages().contains(language);
+  }
+
   /**
    * @param target target language
    * @return PsiFile for given language, or {@code null} if the language not present