Normative: Do not read from empty [[CycleRoot]] in GatherAvailableAncestors#3769
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nicolo-ribaudo wants to merge 2 commits into
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Normative: Do not read from empty [[CycleRoot]] in GatherAvailableAncestors#3769nicolo-ribaudo wants to merge 2 commits into
nicolo-ribaudo wants to merge 2 commits into
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nicolo-ribaudo
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The rendered spec for this PR is available as a single page at https://tc39.es/ecma262/pr/3769 and as multiple pages at https://tc39.es/ecma262/pr/3769/multipage . |
heimskr
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Mar 18, 2026
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For what it's worth, this spec change is indeed equivalent to my fix in V8. |
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linusg
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We might want to make sure there's a test that catches this, otherwise LGTM.
guybedford
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Read through carefully and I agree this correctly distinguishes early sync errors from the cycle root error handling.
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Fixes #3766. See #3766 (comment) for a more detailed analysis.
Marking this as normative as we did for #3583, but (same as for that PR) this is aligning the spec with the commitee's desired behavior and thus does not need explicit consensus.
I checked V8's ans SM's implementations after writing this patch, and it seems like SM does exactly what this spec change does. V8 has a different but equivalent approach (it checks that the [[CycleRoot]] is not empty, and asserts that it being empty implies that the module errored, cc @o-).
cc @heimskr for your WebKit module loader rewrite.