Node 24.8.0 has a regression in VM #59866

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1. targos commented on Sep 12, 2025

   

   targos

   on Sep 12, 2025

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   @legendecas
2. alexander-akait commented on Sep 12, 2025

   

   alexander-akait

   on Sep 12, 2025

   Last edited by alexander-akait

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   Found reproducible test example:

   const vm = require("vm");
   
   (async () => {
   	const module = new vm.SourceTextModule("console.log('Works')", {
   		initializeImportMeta(meta) {
   			// Note: this object is created in the top context. As such,
   			// Object.getPrototypeOf(import.meta.prop) points to the
   			// Object.prototype in the top context rather than that in
   			// the contextified object.
   			meta.prop = {};
   		}
   	});
       // Works fine with 24.7.0, broken with 24.8.0
   	if (module.instantiate) module.instantiate();
   	await module.link(() => {});
   	await module.evaluate();
   })();

   Not sure if this is expected or not? I known instantiate is not in official API, but we have tests cases from node v10 to v24 and this code works before
3. daeyeon

   added

   vmIssues and PRs related to the vm subsystem.Issues and PRs related to the vm subsystem.

   on Sep 12, 2025
4. joyeecheung commented on Sep 14, 2025

   

   joyeecheung

   on Sep 14, 2025

   Last edited by joyeecheung

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   Do you know why you were calling instantiate()? It's not an API until it was added in 24.8.0 #59000 - before that it was not undocumented, but just non-existent and therefore never called; now that there's a new API that's happened to be named instantiate(), the code is invoking it which it shouldn't (because link() already does instantiation. In the new API design, you either use linkRequests() + instantiate() which allows you to do it in two different steps, or you use link() that does things in one step).
5. joyeecheung commented on Sep 14, 2025

   

   joyeecheung

   on Sep 14, 2025

   Last edited by joyeecheung

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   It seems there was a different instantiate() method that existed during v10-v12.11.0 until removed by #29776 , and then in v24.8.0, a new but different instantiate() was added; I think for your use case, you can either

   1. change if (module.instantiate) to if (module.instantiate && process.version < "v13") (or other more robust way to check that it's the instantiate() method below 13)
   2. just remove that instantiate() branch if you are not particularly interested in supporting this use case for Node.js v10-v12.11.0 in 2025.

   👍React with 👍1Reacted by Chengzhong Wu
6. legendecas commented on Sep 14, 2025

   

   legendecas

   on Sep 14, 2025

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   It seems like webpack is still running tests against Node.js v10.x: https://github.com/webpack/webpack/actions/runs/17681438488/job/50256443191?pr=19901. I'd agree with Joyee that this will need a version guard to continue use the already removed experimental behavior.

   👍React with 👍1Reacted by hai-x
7. legendecas commented on Sep 17, 2025

   

   legendecas

   on Sep 17, 2025

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   As explained in #59866 (comment), this is not a regression that needs a fix in Node.js. Feel free to re-open if you think this is not the case.
8. legendecas

   closed this as not plannedon Sep 17, 2025