1597472 - Audit nsIDocShellTreeItem usage in nsDocumentViewer::SetDocumentInternal in layout/base/nsDocumentViewer.cpp

Status: NEW

(Core :: Layout, defect, P5)

Description

[Kannan Vijayan [:djvj]]

In file layout/base/nsDocumentViewer.cpp

Just removes all children from the parent in the DocShell tree.

Cannot remove as long as DocShell tree is still in codebase. This logic be removed once all uses of the docshell tree are eliminated.

Comment 1

[Chris Peterson [:cpeterson]]

Kannan says replacing nsIDocShellTreeItem calls should block enabling Fission in Nightly (M6).

Comment 2

[Chris Peterson [:cpeterson]]

Moving to Layout triage.

Please audit this use of the nsIDocShellTreeItem interface. With Fission enabled, Documents and nsDocShells for related frames, such as subframes and parent documents, may not be available within the current process and the corresponding nsIDocShellTreeItem methods will return null

If this code works as-is with Fission, we don't need to remove this usage of nsIDocShellTreeItem until when we remove nsIDocShellTreeItem entirely (bug 1607591) after we ship Fission MVP.

Fission documentation about replacing nsIDocShellTree Item:
https://wiki.mozilla.org/Project_Fission/DocShell_Tree_Replace

:farre's presentation with examples of replacing nsIDocShellTreeItem with BrowsingContext, WindowContext, SyncedContexts, and BrowsingContextGroup:
https://docs.google.com/presentation/d/1K4j6ngty64TZjJNS5qH-MBoOm3TI2dJedVsbH8jUhKE/edit#slide=id.g6e35225e5d_1_264

Comment 3

[Release mgmt bot [:sylvestre / :calixte / :marco for bugbug]]

The priority flag is not set for this bug.
:jwatt, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 4

[Chris Peterson [:cpeterson]]

Auditing whether this use of nsIDocShellTreeItem breaks when Fission is enabled blocks Fission Nightly.

Comment 5

[Nika Layzell [:nika] (ni? for response)]

This is an internal implementation detail of how nsIDocShellTreeItem manages its children list, and so doesn't need to be changed as part of fission.