Greptile Summary

This PR restores Erlang WASM engine parity by committing the pre-validated tree-sitter-erlang.wasm binary directly alongside a .gitignore negation rule, sidestepping the malicious npm package (GHSA-rphw-c8qj-jv84) that was removed in #1478.

• .gitignore correctly places !grammars/tree-sitter-erlang.wasm after the grammars/*.wasm wildcard — the ordering ensures git tracks only this one file.
• build-wasm.ts comment is well-maintained with fully self-contained rebuild instructions; the Erlang entry is kept out of the grammars array so a normal build:wasm run never overwrites the committed binary.
• The committed WASM was manually validated against the project's own criteria (magic bytes, single grammar export, import allowlist), but no checksum file or CI step persists that validation for future changes to the file.

Confidence Score: 5/5

Safe to merge — the change commits a pre-validated binary and tightly scopes git tracking to that single file, with no build logic changes that affect other grammars.

The .gitignore negation is correctly ordered, the build script comment is accurate, and the Erlang entry is intentionally omitted from the grammars array so normal builds cannot accidentally overwrite the committed file. The only open question is whether a future binary swap would be caught automatically, but that is a forward-looking hardening gap rather than a defect in the current change.

grammars/tree-sitter-erlang.wasm — pre-built binary with no companion checksum; worth a second set of eyes if the team wants ongoing tamper-detection.

Important Files Changed

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[npm run build:wasm] --> B{Erlang entry in grammars array?}
    B -- No\n(current state) --> C[Committed grammars/tree-sitter-erlang.wasm\nuntouched — used as-is]
    B -- Yes\n(during rebuild) --> D[build-wasm.ts runs\nnpx tree-sitter build --wasm]
    D --> E[validateGrammar:\nmagic bytes ✓\nsingle tree_sitter_erlang export ✓\nno disallowed imports ✓]
    E -- Pass --> F[New WASM overwrites committed file]
    E -- Fail --> G[WASM deleted, error logged]
    C --> H[WASM engine loads Erlang grammar\nParity with native engine restored]
    F --> H

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flowchart TD
    A[npm run build:wasm] --> B{Erlang entry in grammars array?}
    B -- No\n(current state) --> C[Committed grammars/tree-sitter-erlang.wasm\nuntouched — used as-is]
    B -- Yes\n(during rebuild) --> D[build-wasm.ts runs\nnpx tree-sitter build --wasm]
    D --> E[validateGrammar:\nmagic bytes ✓\nsingle tree_sitter_erlang export ✓\nno disallowed imports ✓]
    E -- Pass --> F[New WASM overwrites committed file]
    E -- Fail --> G[WASM deleted, error logged]
    C --> H[WASM engine loads Erlang grammar\nParity with native engine restored]
    F --> H

Reviews (3): Last reviewed commit: "fix: remove executable bit from tree-sit..." | Re-trigger Greptile

Addressed Greptile feedback:

• P2 (executable bit): Removed executable bit from grammars/tree-sitter-erlang.wasm using git update-index --chmod=-x (100755 → 100644). WASM is a data file and must not be executable.
• P2 (rebuild comment): Expanded the inline rebuild instructions in scripts/build-wasm.ts to include the actual array entry, making them fully self-contained.

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