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cjs: find-my-way@9 init throws 'Cannot convert undefined or null to object' — blocks #6559 e2e #6587
Description
Found while landing #6559 (PR #6584): find-my-way@9 compiles natively (compilePackages) but throws TypeError: Cannot convert undefined or null to object at load — before any route is registered or any runtime-generated code runs.
Uncharacterized beyond the failure point: something during module init passes undefined/null into an Object.* operation (likely Object.keys/assign/setPrototypeOf over a value perry resolves differently at CJS init — needs a bisect into find-my-way's init graph: handler-storage maps, http-methods table, or its Object.create(null) trees).
Repro: the #[ignore]d e2e in crates/perry/tests/issue_6559_real_libs_e2e.rs (PERRY_REQUIRE_NPM_E2E=1 … -- --ignored).
Blocks: #6559 real-library acceptance (router leg), kimi-code target #6565 (fastify routing = find-my-way). Interpreter side already proven against find-my-way's captured matcher codegen incl. new NullObject() on a host class (PR #6584 fixtures).
Activity
fix(runtime): instanceof primitive LHS returns false uniformly (CodeR…
fix(runtime): instanceof with null/undefined LHS returns false, not t…
proggeramlug commentedon Jul 18, 2026
Resolved by #6598 (merged to
mainas 49db1ac).Root cause:
OrdinaryHasInstance(ECMA-262 7.3.21) with anull/undefinedleft operand threwTypeError: Cannot convert undefined or null to objectinstead of returningfalse. find-my-way@9'sFindMyWay(opts)is called withoutnew, so itsRouterbody evaluatesthis instanceof Routerwiththis === undefined; because the RHS is a function value, it routed throughjs_instanceof_dynamic's prototype-walk tail (ordinary_has_instance_prototype_walk), which calledgetPrototypeOf(undefined)and aborted module init before any route was registered.Fix: the prototype walk now short-circuits to
falsefor every non-object LHS (null/undefined/boolean/int32/string/bigint/symbol), per step 3 ("If Type(O) is not Object, return false"), andSymbol() instanceof Objectis nowfalse. Verified byte-identical to Node across 26 instanceof cases;real_find_my_way_routerincrates/perry/tests/issue_6559_real_libs_e2e.rsis un-ignored and green.Note: one minor CodeRabbit suggestion — set
PERRY_REQUIRE_NPM_E2E=1for thee2e-scopedCI job so that e2e can't silently skip — was not included in #6598 and remains as optional CI hardening.