RESOLVED FIXED313615
[Site Isolation] Enable same-site in-process BFCache under Site Isolation 
https://bugs.webkit.org/show_bug.cgi?id=313615
Summary [Site Isolation] Enable same-site in-process BFCache under Site Isolation
Basuke Suzuki
Reported 2026-04-28 21:46:03 PDT
Under Site Isolation, BackForwardCache::addIfCacheable(HistoryItem&, Page*) unconditionally returns false, blocking ALL in-process BFCache even for same-site navigations with no cross-site iframes. For pages with no RemoteFrame descendants (no cross-site iframes), in-process BFCache should work exactly as without SI — there are no RemotePageProxy objects in the BCG, no iframe processes to coordinate. Step 1: Relax the SI guard to allow same-site BFCache when no cross-site iframes exist. Step 2 (future): UIProcess coordination for iframe process suspension during same-site BFCache with cross-site iframes. rdar://175820428
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Radar WebKit Bug Importer
Comment 1 2026-05-05 21:46:12 PDT
<rdar://problem/176327855>
Basuke Suzuki
Comment 2 2026-05-08 17:01:24 PDT
Pull request: https://github.com/WebKit/WebKit/pull/64584
EWS
Comment 3 2026-05-09 07:40:13 PDT
Committed 312946@main (90d12c87eba1): <https://commits.webkit.org/312946@main> Reviewed commits have been landed. Closing PR #64584 and removing active labels.
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