Bug 238460

Summary: AX: Don't detach children in AXIsolatedTree::applyPendingChanges for nodes being updated (removed and added)
Product: WebKit Reporter: Tyler Wilcock <tyler_w>
Component: AccessibilityAssignee: Tyler Wilcock <tyler_w>
Status: RESOLVED FIXED    
Severity: Normal CC: aboxhall, andresg_22, apinheiro, cfleizach, dmazzoni, ews-watchlist, jcraig, jdiggs, samuel_white, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
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Patch
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Description Tyler Wilcock 2022-03-28 10:52:08 PDT 
In AXIsolatedTree::updateNode, we perform the update by queuing the node to be removed, and then queueing it to be added.

When performing the removal in AXIsolatedTree::applyPendingChanges, we call AXCoreObject::detach, which unconditionally calls AXCoreObject::detachRemoteParts. Specifically, AXIsolatedObject::detachRemoteParts detaches all the object's children from the itself (by setting their m_parentID to zero). Then, when we start applying m_pendingAppends, we re-add the object, but never re-attach the children, resulting in a broken tree.
Comment 1 Radar WebKit Bug Importer 2022-03-28 10:52:19 PDT 
<rdar://problem/90932915>
Comment 2 Tyler Wilcock 2022-03-28 11:06:38 PDT 
Created attachment 455930 [details]
Patch
Comment 3 Tyler Wilcock 2022-03-28 19:07:16 PDT 
Created attachment 455979 [details]
Patch
Comment 4 Andres Gonzalez 2022-03-29 04:30:47 PDT 
(In reply to Tyler Wilcock from comment #3)
> Created attachment 455979 [details]
> Patch

--- a/Source/WebCore/accessibility/isolatedtree/AXIsolatedTree.cpp
+++ a/Source/WebCore/accessibility/isolatedtree/AXIsolatedTree.cpp

@@ -307,7 +307,7 @@ void AXIsolatedTree::updateNode(AXCoreObject& axObject)

-    m_pendingNodeRemovals.append(axID);
+    m_pendingNodeRemovals.append(std::make_pair(axID, AccessibilityDetachmentType::ElementChanged));

Can we use an initializer list for the pair?

    m_pendingNodeRemovals.append({ axID, AccessibilityDetachmentType::ElementChanged });

@@ -545,10 +545,11 @@ void AXIsolatedTree::applyPendingChanges()

+        auto axID = removal.first;

Don't need this local variable.
Comment 5 Tyler Wilcock 2022-03-29 08:38:19 PDT 
Created attachment 456028 [details]
Patch
Comment 6 EWS 2022-03-29 17:35:36 PDT 
Committed r292086 (249013@main): <https://commits.webkit.org/249013@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 456028 [details].