Skip to content

[[CycleRoot]] is expected on all evaluated modules, but it's not set on modules that throw synchronously #3582

Open
@nicolo-ribaudo

Description

@nicolo-ribaudo

Test case:

// entrypoint.js
await import("./foo.js").catch(() => {});
await import("./foo.js");
// foo.js
throw 1;

When we call module.Evaluate() for the first dynamic import:

  • Step 8 of Evaluate() calls InnerModuleEvaluation(module)
  • Step 13.a of InnerModuleEvaluation does ? module.ExecuteModule()
    • module.ExecuteModule() returns an abrupt completion, so we return early without going to step 16.b.viii (which is the only place in the spec that sets module.[[CycleRoot]])
  • Step 9 of Evaluate sets module.[[Status]] to ~evaluated~ and module.[[EvaluationError]] to the throw completion.

When we call module.Evaluate() for the second dynamic import:

  • Step 3 of Evaluate() does "If module.[[Status]] is either ~evaluating-async~ or ~evaluated~, set module to module.[[CycleRoot]]".
  • [[CycleRoot]] was never set on module, so it's ~empty~.
  • Step for tries to read [[TopLevelCapability]] from it, which doesn't make sense because it's not a module record.

Step-by-step debugger for the first import: https://nicolo-ribaudo.github.io/es-module-evaluation/#s=QQo%3D&c=&a=Cg%3D%3D&f=QQ%3D%3D

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions