(protobuf) Fix EnumLookup hash-area sizing - #773
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`EnumLookup.Big.construct()` called `findSize(byId.size())` on the line after `byId` was created and before it was populated, so the result was always `findSize(0)` == 8 regardless of enum size. Every protobuf enum therefore got an 8-slot primary + 4-slot secondary hash area. A 100-value enum pushed ~88 entries into the linearly-scanned spill area, and grew the backing arrays 4 slots at a time while building it. Sizing from `entries` gives 128 primary slots and 19 spills for the same enum. Correctness was never affected -- the spill scan finds everything -- but the cost is paid on every enum-valued field write. Adds a regression test, plus two package-private accessors on `EnumLookup.Big` so the hash-area sizing can be asserted. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Split out of #772.
byIdis created on the line above and populated in the loop below, so this is alwaysfindSize(0)== 8. Every protobuf enum, regardless of size, got an 8-slot primary + 4-slot secondary hash area. A 100-value enum pushed ~88 entries into the linearly-scanned spill area, and grew the backing arrays 4 slots at a time while building it.Sizing from
entriesinstead gives 128 primary slots and 19 spills for the same enum.Correctness was never affected — the spill scan finds everything — so this is purely lookup and construction cost, paid on every enum-valued field write.
Pre-dates the 2.x -> 3.x rename and is present on
2.21too; targeting3.xfor now, happy to redo against2.21and merge forward if you prefer.Test
EnumLookupTest— a 100-value enum resolves every entry by name and by index, and the primary hash area is 128 slots rather than 8. Needed two package-private accessors (hashArea(),spillCount()) onEnumLookup.Big.Full
protobufmodule test suite passes.🤖 Generated with Claude Code