ADR-0017: CoffeeScript and LiveScript run through a Node sidecar

• Status: Accepted
• Date: 2026-09-20
• Derives from: design.md § What each extractor has to get right, § Open questions (the sidecar); dependency-cruiser coverage § Extraction and resolution
• Constrains: architecture.md § Extractors
• Implemented by: Wave 3 plan

Context

dependency-cruiser supports CoffeeScript and LiveScript through their transpilers. No Rust parser exists for either, none of the oracle repositories uses them, and nothing may be dropped from the superset.

Decision

• --sidecar node spawns dependency-cruiser for .coffee, .litcoffee, .ls, .cjsx and .csx files and merges the resulting edges into the graph document, marked sidecar: true.
• Without the flag, such a file makes the run untrustworthy (exit 2, ADR-0008) with a named reason, never a silent skip.
• This is the only place the tool spawns Node, and the coverage tab says so. The specs that exercise it sit in conformance/excluded.json until the sidecar lands in wave 3, after which that list must be empty.

Consequences

• The superset claim holds without a native parser for two languages with no active oracle.
• The sidecar is exercised only by dependency-cruiser's own fixtures, which is documented.

Alternatives considered

• Drop the two languages. Rejected: "nothing is dropped" is the promise.
• Port the transpilers. Rejected: cost with no user.