Type Alias CauslEngineIdentity

CauslEngineIdentity:
    | { bridge: BridgeId; engine: "rust-wasm"; mode: "rust-ssot" }
    | { bridge: BridgeId; engine: "typescript"; mode: "js-ssot" }
    | {
        bridge: undefined;
        engine: "typescript";
        mode: "ts-floor";
        tsFloorReason: CauslTsFloorReason;
    }

A frozen observation of which engine executed a particular Graph (#295).

Type declaration

  • { bridge: BridgeId; engine: "rust-wasm"; mode: "rust-ssot" }
    • Readonlybridge: BridgeId

      The canonicalised FFI bridge the artefact was instantiated through. Always present on this arm.

    • Readonlyengine: "rust-wasm"

      The Rust core in the wasm artefact executed this graph.

    • Readonlymode: "rust-ssot"

      Built through this subpath with the Rust core canonical.

  • { bridge: BridgeId; engine: "typescript"; mode: "js-ssot" }
    • Readonlybridge: BridgeId

      The canonicalised FFI bridge. Present — and load-bearing — despite engine reading 'typescript': an artefact was instantiated, and this graph paid for it.

    • Readonlyengine: "typescript"

      The TS closure executed this graph's adopter-visible commits — even though an artefact WAS instantiated and is running as a shadow. This is the case a process-wide preload predicate gets wrong.

    • Readonlymode: "js-ssot"

      Built through this subpath, pinned to the §18A.7 TS floor opt. Unreachable since 0.5.0 (#280 removed the opt); the arm stays declared until 0.6.0 so an adopter's exhaustive match keeps compiling.

  • {
        bridge: undefined;
        engine: "typescript";
        mode: "ts-floor";
        tsFloorReason: CauslTsFloorReason;
    }
    • Readonlybridge: undefined

      No artefact was instantiated, so there is no bridge to name.

    • Readonlyengine: "typescript"

      The TS closure executed this graph.

    • Readonlymode: "ts-floor"

      No wasm artefact was instantiated for this graph.

    • ReadonlytsFloorReason: CauslTsFloorReason

      Why this graph is on the floor, to the precision this subpath can establish; see CauslTsFloorReason.

Remarks

An observation, not a claim: every field is stamped at construction from the values the construct actually applied, not re-derived later from process state that may since have changed.

A DISCRIMINATED UNION, not a flat record, because two invariants hold that a flat record can only assert in prose:

  • engine is a pure function of mode — 'rust-ssot' is the only mode whose adopter-visible commits run in Rust.
  • bridge is present exactly when an artefact was instantiated, which is exactly when mode !== 'ts-floor'.

As prose those are comments a later edit falsifies silently; as arms they are checked on every build, and if (id.mode === 'ts-floor') / if (id.engine === 'rust-wasm') narrow bridge for the caller instead of making them assert it. The shape is free to adopt now and expensive later: every consumer that has written id.bridge! is a consumer the union would have to break.

It also made #280 a deletion rather than a semantic change: that issue removed the floor opt, which here is one arm gone inert whole, with the compiler naming every call site that still matches on it.

Future widenings — #296's build identifier first among them — land at the TAIL of EVERY arm, never by reordering or renaming, so a consumer that destructures { engine } today is unaffected.

Settings

Member Visibility