[webkit-changes] [WebKit/WebKit] ecf63c: [Debug] ASSERTION FAILED: m_phase == ViewTransitio...

[Vitaly Dyachkov]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: ecf63ceef8cf9afc28b7bbbd1eb7ad0582929542
      https://github.com/WebKit/WebKit/commit/ecf63ceef8cf9afc28b7bbbd1eb7ad0582929542
  Author: Vitaly Dyachkov <vitaly at igalia.com>
  Date:   2023-12-12 (Tue, 12 Dec 2023)

  Changed paths:
    M LayoutTests/platform/glib/TestExpectations
    M LayoutTests/platform/mac/TestExpectations
    M Source/WebCore/dom/ViewTransition.cpp
    M Source/WebCore/dom/ViewTransition.h

  Log Message:
  -----------
  [Debug] ASSERTION FAILED: m_phase == ViewTransitionPhase::Done || m_phase == ViewTransitionPhase::PendingCapture
https://bugs.webkit.org/show_bug.cgi?id=265868

Reviewed by Tim Nguyen.

During each invocation of `Page::updateRendering()`, the `Document`
triggers the `setupViewTransition()` method of `m_activeViewTransition`
when it's in the `ViewTransitionPhase::PendingCapture` phase.

The `ViewTransition` first updates its state within the
`callUpdateCallback()` method, which is executed asynchronously.

This can lead to a situation where the active `ViewTransition` has been
set up, but its state remains `ViewTransitionPhase::PendingCapture`
when the `Document` checks it.

In such cases, the `Document` may call `setupViewTransition()` more
than once.

To address this issue, this patch introduces a
`ViewTransitionPhase::Capturing` state, indicating that the transition
setup is complete, but the callback has not been called yet.

Note that this phase is not part of the spec [1].

1. https://drafts.csswg.org/css-view-transitions/#viewtransition-phase

* Source/WebCore/dom/ViewTransition.cpp:
(WebCore::ViewTransition::callUpdateCallback):
(WebCore::ViewTransition::setupViewTransition):
* Source/WebCore/dom/ViewTransition.h:

Canonical link: https://commits.webkit.org/271959@main