[COOP] "check if enforcing report-only COOP would require a browsing context group switch" algorithm doesn't seem to match WPT tests

[cdumez]

I am referring to this algorithm.

The last subtest of html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin.https.html, does not expect a report when navigating a popup same-origin with COOP-ReportOnly=same-origin; report-to="${popupReportOnlyEndpoint.name}". The active document COOP (not reportOnly) is "same-origin".

The algorithm says:

If the result of checking if COOP values require a browsing context group switch given isInitialAboutBlank, responseOrigin, activeDocumentNavigationOrigin, responseCOOP's report-only value and activeDocumentCOOPReportOnly's report-only value is false, then return false.

responseCOOP's report-only value is 'same-origin' and activeDocumentCOOPReportOnly's report-only value is 'unsafe-none'. They don't match so this should trigger a switch and we shouldn't return false here.

If the result of checking if COOP values require a browsing context group switch given isInitialAboutBlank, responseOrigin, activeDocumentNavigationOrigin, responseCOOP's value and activeDocumentCOOPReportOnly's report-only value is true, then return true.

responseCOOP's value is 'unsafe-none' and activeDocumentCOOPReportOnly's report-only value is 'unsafe-none' and we are same-origin. As a result, I wouldn't expect a switch here and we shouldn't return true here.

If the result of checking if COOP values require a browsing context group switch given isInitialAboutBlank, responseOrigin, activeDocumentNavigationOrigin, responseCOOP's report-only value and activeDocumentCOOPReportOnly's value is true, then return true.

responseCOOP's report-only value is 'same-origin' and activeDocumentCOOPReportOnly's value is 'unsafe-none'. They don't match, therefore, I would expect a switch and we should return true.

As a result of returning true here, I think a report should be sent. Am I missing something? Is the subtest wrong or is there an issue with the algorithm in the spec?

[cdumez]

cc @camillelamy.

[cdumez]

Oh, when I implemented this part of the spec, then this subtest started passing:

If browsingContext's group's browsing context set's size is greater than 1, then:
Queue a violation report...

I was missing the check of the browsing context group size.