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vm: behavior with --abort-on-uncaught-exception #13258
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I agree, this looks like a bug.
This seems like something that could be handled in
ShouldAbortOnUncaughtException().I’m not sure – why doesn’t V8 see the
try { … } catch {}block here? And how would we tell whether the exception would be caught or not?My understanding of the code I linked (and I could definitely be wrong) is that the
try...catchwould be seen and catch the error, but it aborts before getting back to that point because it is an external handler. It might even be considered a V8 bug, but the comment in that code block seems deliberate./cc @nodejs/v8
I’m not sure – why doesn’t V8 see the try { … } catch {} block here?
new vm.Script(...)callsContextifyScript::New(). It has av8::TryCatch(an EXTERNAL handler, per the comment Colin linked to) that V8 sees as the top handler.I'd say this is a bug but I don't have a good suggestion off the top of my head on how to fix it.
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The TryCatch is there in order to decorate SyntaxError exceptions. Simply removing it is going to break more than it fixes and moving it to after the call to
v8::ScriptCompiler::CompileUnboundScript()won't work. -
Naively removing the CAUGHT_BY_EXTERNAL check from V8 breaks
--abort_on_uncaught_exceptionbecause there is always a TryCatch on the stack in node. -
That bottom TryCatch can't be removed because that breaks
process.on('uncaughtException')and a host of other things.
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Even if we can't fix this in the general case, do you think it's worth adding an option to the
vmfunctions to control this behavior?As this is very brittle to changes, I'd prefer not to add the option. As Ben said, most solutions would break more than fix. Do you have a use case for it? Would it be enough to note the bug in the documentation?
I'm definitely in favor of at least documenting this.
I don't personally have a need for the option. However, running with
--abort-on-uncaught-exceptionis a somewhat common practice in production, and this bug kind of makes thevmmodule incompatible with that. That said, I don't recall ever seeing this reported before.Reacted by Aaron Hogue and Anna Henningsen- added a commit that references this issue
on Dec 21, 2017 - added a commit that references this issue
on Jul 27, 2026
In the following code, the
vm.Script()constructor throws an exception. When node is run normally, the exception is caught and node exits cleanly. However, when run with--abort-on-uncaught-exception, the exception is treated as uncaught.Before attempting to fix this, I wanted to make sure there is agreement that this is a bug. This seems like something that could be handled in
ShouldAbortOnUncaughtException().Related: nodejs/node-report#60