• Daniel Clark's avatar
    Fix top-level await crash from synthetic module being evaluated twice · f033e2a1
    Daniel Clark authored
    With top-level await, when Evaluate is performed on an already-evaluated
    synthetic module, Module::InnerEvaluate returns undefined.  This breaks
    top-level await's assumption that the returned value is always a
    promise.
    
    In order to make SyntheticModule's behavior consistent with
    SourceTextModule, the top_level_capability field is moved up to Module
    and SyntheticModule::Evaluate places the promise returned from the
    host's evaluation steps in that field.  Now SourceTextModule and
    SyntheticModule can share the same code to handle the case where the
    module is either kErrored or kEvaluated, so the code for this
    is moved up to Module.
    
    Thus, SyntheticModule is now guaranteed to return the
    promise from the evaluation steps even on subsequent Evaluate() calls.
    
    Unfortunately Node hasn't yet updated their EvaluationStepsCallback
    to return a Promise, so we can't yet assume that the returned value
    is a Promise without breaking Node.  So, this change also adds a clause
    to check for this condition and create a new resolved Promise if one
    was not provided by the callback steps.  This could eventually be
    removed once Node's callback steps are updated for top-level await.
    
    Change-Id: I2d6ae918abfeba9e3a757838502d4df92946edaa
    Bug: v8:11398
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2673794Reviewed-by: 's avatarCamillo Bruni <cbruni@chromium.org>
    Reviewed-by: 's avatarDominik Inführ <dinfuehr@chromium.org>
    Commit-Queue: Dan Clark <daniec@microsoft.com>
    Cr-Commit-Position: refs/heads/master@{#72629}
    f033e2a1
synthetic-module.cc 5.66 KB