(Firefox Android) Backspace at beginning of line error

[pablojan]

In FF Android backspace keystroke at beginning of new line generates a set of composition events (IME) mutating the DOM but no a proper key event [1].

In this situation the editor tries to undo DOM changes (DomMutationReverter) when detecting the DOM events (EditorEventHandler.handleEventInner:346). Result is a inconsistency of the document in-memory model.

[1] Composition events:

("DOMNodeRemoved","BR")
("DOMSubtreeModified","DIV")
("DOMNodeInserted","BR")
("DOMSubtreeModified","DIV")
("DOMNodeRemoved","DIV")
("DOMSubtreeModified","UL")
("DOMNodeRemoved","BR")
("DOMSubtreeModified","DIV")

[pablojan]

Here some code used to detect that event sequence:

  public static class DetectorState {
    String event;
    String target;
    
    public DetectorState(String e, String t) {
      this.event = e;
      this.target = t;
    }
    
  }
  private static DetectorState[] backspaceDetectorStateSpace = {
              new DetectorState("DOMNodeRemoved","BR"),
              new DetectorState("DOMSubtreeModified","DIV"),
              new DetectorState("DOMNodeInserted","BR"),
              new DetectorState("DOMSubtreeModified","DIV"),
              new DetectorState("DOMNodeRemoved","DIV"),
              new DetectorState("DOMSubtreeModified","UL"),
              new DetectorState("DOMNodeRemoved","BR"),
              new DetectorState("DOMSubtreeModified","DIV") };
  
  private int currentBackspaceDetectorState = 0;
      
...

      if (backspaceDetectorStateSpace[currentBackspaceDetectorState].event.equalsIgnoreCase(event.getType()) &&
          backspaceDetectorStateSpace[currentBackspaceDetectorState].target.equalsIgnoreCase(event.getTarget().getTagName())) {
        currentBackspaceDetectorState++;
      } else {
        currentBackspaceDetectorState = 0;
      }
           
      if (currentBackspaceDetectorState == 8) {
        currentBackspaceDetectorState = 0;
        EditorStaticDeps.logger.trace().log("Detected backspace mutation set");
        
        EditorStaticDeps.startIgnoreMutations();
        
        Point<ContentNode> caret;
        // refreshEditorWithCaret(event);
        caret = editorInteractor.getSelectionPoints().getAnchor();
        ContentNode node = caret.getContainer();
        ContentElement element = node.asElement();
        if (element == null)
          element = node.getParentElement();
        
        //node.getMutableDoc().deleteNode(element);
        // editorInteractor.rebiasSelection(CursorDirection.FROM_RIGHT);        
        // router.handleBackspace(node, event);
        
        EditorStaticDeps.endIgnoreMutations();
      }