Possibility to mark a file type as secondary so it's not returned by Language.getAssociatedFileType()

GitOrigin-RevId: 94fa97faccc17f778db16dda380cf029b71a175f

platform/core-api/src/com/intellij/lang/Language.java

@@ -161,13 +161,19 @@ public abstract class Language extends UserDataHolderBase {
   @ApiStatus.Internal
   public LanguageFileType findMyFileType(FileType[] types) {
     for (final FileType fileType : types) {
-      if (fileType instanceof LanguageFileType && ((LanguageFileType)fileType).getLanguage() == this) {
-        return (LanguageFileType)fileType;
+      if (fileType instanceof LanguageFileType) {
+        final LanguageFileType languageFileType = (LanguageFileType)fileType;
+        if (languageFileType.getLanguage() == this && !languageFileType.isSecondary()) {
+          return languageFileType;
+        }
       }
     }
     for (final FileType fileType : types) {
-      if (fileType instanceof LanguageFileType && isKindOf(((LanguageFileType)fileType).getLanguage())) {
-        return (LanguageFileType)fileType;
+      if (fileType instanceof LanguageFileType) {
+        final LanguageFileType languageFileType = (LanguageFileType)fileType;
+        if (isKindOf(languageFileType.getLanguage()) && !languageFileType.isSecondary()) {
+          return languageFileType;
+        }
       }
     }
     return null;

platform/core-api/src/com/intellij/openapi/fileTypes/LanguageFileType.java

@@ -29,13 +29,25 @@ import java.nio.charset.Charset;
  */
 public abstract class LanguageFileType implements FileType{
   private final Language myLanguage;
+  private final boolean mySecondary;
 
   /**
    * Creates a language file type for the specified language.
    * @param language The language used in the files of the type.
    */
   protected LanguageFileType(@NotNull final Language language) {
+    this(language, false);
+  }
+
+  /**
+   * Creates a language file type for the specified language.
+   * @param language The language used in the files of the type.
+   * @param secondary If true, this language file type will never be returned as the associated file type for the language.
+   *                  (Used when a file type is reusing the language of another file type, e.g. XML).
+   */
+  protected LanguageFileType(@NotNull final Language language, boolean secondary) {
     myLanguage = language;
+    mySecondary = secondary;
   }
 
   /**
@@ -57,6 +69,10 @@ public abstract class LanguageFileType implements FileType{
     return false;
   }
 
+  public boolean isSecondary() {
+    return mySecondary;
+  }
+
   @Override
   public String getCharset(@NotNull VirtualFile file, @NotNull final byte[] content) {
     return null;

platform/platform-impl/src/com/intellij/openapi/fileTypes/impl/FileTypeBean.java

@@ -63,8 +63,8 @@ public class FileTypeBean extends AbstractExtensionPointBean {
   public String fileNamesCaseInsensitive;
 
   /**
-   * For file types that extend {@link LanguageFileType}, this must be set to the ID of the language
-   * returned by {@link LanguageFileType#getLanguage()}.
+   * For file types that extend {@link LanguageFileType} and are the primary file type for the corresponding language, this must be set
+   * to the ID of the language returned by {@link LanguageFileType#getLanguage()}
    */
   @Attribute("language")
   public String language;

python/src/META-INF/python-core-common.xml

@@ -21,7 +21,7 @@
               extensions="py;pyw;"
               implementationClass="com.jetbrains.python.PythonFileType"
               fieldName="INSTANCE"/>
-    <fileType name="Qt UI file" language="XML" extensions="ui" implementationClass="com.jetbrains.pyqt.QtUIFileType" fieldName="INSTANCE"/>
+    <fileType name="Qt UI file" extensions="ui" implementationClass="com.jetbrains.pyqt.QtUIFileType" fieldName="INSTANCE"/>
     <fileType name="XML" language="XML" extensions="qrc"/>
     <fileTypeDetector implementation="com.jetbrains.python.PyFileTypeDetector"/>
     <editorHighlighterProvider filetype="Python" implementationClass="com.jetbrains.python.PyEditorHighlighterProvider"/>

python/src/com/jetbrains/pyqt/QtFileType.java

@@ -32,7 +32,7 @@ public abstract class QtFileType extends LanguageFileType implements INativeFile
   private final String myDefaultExtension;
 
   QtFileType(String name, String description, String defaultExtension) {
-    super(XMLLanguage.INSTANCE);
+    super(XMLLanguage.INSTANCE, true);
     myName = name;
     myDescription = description;
     myDefaultExtension = defaultExtension;