ECMA-426 DecodeSourceMapSources reads a content slot only while its index
is within sourcesContent, so a shorter array leaves trailing sources
without content and a longer array adds no sources. Local application
analysis and browser collection rejected any length mismatch and dropped
every original from the map.
The content helper now checks only entry types. Browser collection drops
its separate check because the leaf schema already validates every
supplied entry, and the raw records are still budgeted before parsing.
Fixes#2821
Pass typed map objects into the codec and reuse validated TraceMap instances for regular and indexed lookups. Remove whole-map serialization, duplicate leaf decoding, an array-copy wrapper, and the unused offset-validation mode in artifact declaration collection.
Validation: source-map and browser consumer suites (126 tests), declaration tests, and artifact reconstruction boundaries pass. Section overlap checks and raw source declarations remain intact.
Share the ECMA-426 JSON parse view across fetched maps and local point tracing while retaining exact response text, bytes, and digest. Handle BOM and HTTP newline variants without treating unterminated prefixes as valid JSON.
Validation: 89 source-map tests passed; source/runtime build and check:fast passed. Real Chrome 154 CLI and stdio MCP browser verification passed on macOS ARM64.
Riley Gramlich
Yann Roberto
morluto
cyanseek
ysopwnable