core(source-maps): guard against out-of-bounds sourceIndex#16969
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connorjclark merged 1 commit intoApr 17, 2026
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looks good, thanks! CI failures are unrelated. |
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Good fix.. Appreciate the contribution @ducky-duke ! |
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Summary
When a source map has an empty or malformed
sourcesarray,this.#sourceInfos[sourceIndex]isundefined, causing:This crash is caught by the
try/catchin#ensureMappingsProcessed, so the scan continues — but it logs a noisy error and prevents theDuplicatedJavaScriptinsight from running for the affected page.Changes
core/lib/cdt/generated/SourceMap.js: Add optional chaining (?.) to boththis.#sourceInfos[sourceIndex].sourceURLaccess sites inparseMap(lines 384 and 407).build/build-cdt-lib.js:rawCodeToReplaceentry so the fix survives CDT source re-rolls.replaceAllinstead ofreplacein the raw-code replacement loop to ensure all occurrences of a pattern are substituted (previously only the first match was replaced).Reproduction
Run Lighthouse on any page that serves a source map with an empty
sourcesarray or where the VLQ-decoded source index exceeds the bounds of thesourcesarray.