A future enhancement could be to use os.availableParallelism (requires v18.14+), since it's recommended over using os.cpus().length.

Looks like you need an upstream update:

git remote add upstream [email protected]:rollup/plugins.git
git fetch upstream
git merge upstream/master
git push

That should get you set so that Windows Node 20 action passes.

Alright I updated your fork for you from upstream/master and looks like there's a failure on Windows directly related to WASM. Please have a look.

Alright I updated your fork for you from upstream/master and looks like there's a failure on Windows directly related to WASM. Please have a look.

Aren't V8 errors either bugs in node itself or OOMs usually?

Not sure in this case. It doesn't happen on the Ubuntu builds. The existing code doesn't throw this error, so it's possible the changes have surfaced a bug.

Maybe this change is worth a try?

diff --git a/packages/terser/test/test.js b/packages/terser/test/test.js
index 9dabacd..fd36d58 100644
--- a/packages/terser/test/test.js
+++ b/packages/terser/test/test.js
@@ -360,7 +360,9 @@ test.serial('terser preserve vars in nameCache when provided', async (t) => {
 });
 
 test.serial('minify when os.cpus().length === 0', async (t) => {
-  const original = os.cpus;
+  const originalAP = os.availableParallelism;
+  const originalCPUS = os.cpus;
+  os.availableParallelism = null;
   os.cpus = () => [];
   try {
     const bundle = await rollup({
@@ -373,6 +375,7 @@ test.serial('minify when os.cpus().length === 0', async (t) => {
     t.is(output.code, '"use strict";window.a=5,window.a<3&&console.log(4);\n');
     t.falsy(output.map);
   } finally {
-    os.cpus = original;
+    os.availableParallelism = originalAP;
+    os.cpus = originalCPUS;
   }
 });

It passes locally on Node 21.5.0.

@shellscape I can't tell if the tests ran after @easrng last commit. If not, would it be possible to run them again?

@easrng @dasa there are some conflicts that will need to be resolved before I can force the tests to run again. you can fix the pnpm-lock conflict by running pnpm i in the repo root.