1059825 - |content is null| in _setupSwipeGesture

Status: RESOLVED DUPLICATE of bug 1067128

(Firefox :: General, defect)

Description

[(no longer active)]

TypeError: content is null browser.js:8056

  /**
   * Sets up swipe gestures. This includes setting up swipe animations for the
   * gesture, if enabled.
   *
   * @param aEvent
   *        The swipe gesture start event.
   * @return true if swipe gestures could successfully be set up, false
   *         othwerwise.
   */
  _setupSwipeGesture: function GS__setupSwipeGesture(aEvent) {
    if (!this._swipeNavigatesHistory(aEvent)) {
      return false;
    }

    let isVerticalSwipe = false;
    if (aEvent.direction == aEvent.DIRECTION_UP) {
      if (content.pageYOffset > 0) {
        return false;
      }
      isVerticalSwipe = true;
    } else if (aEvent.direction == aEvent.DIRECTION_DOWN) {
      if (content.pageYOffset < content.scrollMaxY) {  // <<< THIS IS WHERE THE ERROR HAPPENS
        return false;
      }
      isVerticalSwipe = true;
    }
    if (isVerticalSwipe) {
      // Vertical overscroll has been temporarily disabled until bug 939480 is
      // fixed.
      return false;
    }

    let canGoBack = gHistorySwipeAnimation.canGoBack();
    let canGoForward = gHistorySwipeAnimation.canGoForward();
    let isLTR = gHistorySwipeAnimation.isLTR;

    if (canGoBack) {
      aEvent.allowedDirections |= isLTR ? aEvent.DIRECTION_LEFT :
                                          aEvent.DIRECTION_RIGHT;
    }
    if (canGoForward) {
      aEvent.allowedDirections |= isLTR ? aEvent.DIRECTION_RIGHT :
                                          aEvent.DIRECTION_LEFT;
    }

    gHistorySwipeAnimation.startAnimation(isVerticalSwipe);

    this._doUpdate = function GS__doUpdate(aEvent) {
      gHistorySwipeAnimation.updateAnimation(aEvent.delta);
    };

    this._doEnd = function GS__doEnd(aEvent) {
      gHistorySwipeAnimation.swipeEndEventReceived();

      this._doUpdate = function (aEvent) {};
      this._doEnd = function (aEvent) {};
    }

    return true;
  },

Comment 1

[Mike Conley (:mconley) (:⚙️) (PTO Dec 22 - Jan 2)]

Are you getting this error while swiping, or during start-up?

Comment 2

[(no longer active)]

(In reply to Mike Conley (:mconley) - Needinfo me! from comment #1)
> Are you getting this error while swiping, or during start-up?

While scrolling.  I'll demo it to you in person.

Comment 3

[a1695754]

I'm guessing this is the same bug that completely breaks trackpad scrolling in Firefox after a single swipe and until you reopen the Firefox window again? 

If so then this should be prioritized. Right now one of the most important interface pieces of Firefox on Mac laptops is broken on Nightly, it's worse than if Enter suddenly stopped working in the AwesomeBar.