Fix getMaxWorkers on termux
#7154
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rplopes
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| @@ -12,7 +12,7 @@ import type {Argv} from 'types/Argv'; | |||
| import os from 'os'; | |||
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| export default function getMaxWorkers(argv: Argv): number { | |||
| if (argv.runInBand) { | |||
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I think it makes more sense to put the check before we do .length (line 20). In this case, we want maxWorkers to override the fallback of 1
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Sure, makes sense. I'll push an updated version.
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Summary
Jest is using
getMaxWorkersto figure out how many CPUs to use in parallel to run the test suite. However, it's using node'sos.cpus(), which unfortunately might not return an answer if the corresponding system information is not available.That's what happens under termux, a popular terminal emulator for Android. Using termux, we get:
This small detail is crashing jest, since it's trying to read
lengthfrom an undefined object:The proposed solution is to default the result of
getMaxWorkersto 1 whenos.cpus()is undefined. This is enough to fix the crash.Test plan
Coverage for
getMaxWorkerswas updated to reflect the new changes.In addition, to verify the goal of the PR was achieved, one can run jest on termux in any version of Android, termux and node. The code without this fix should crash, and with this fix it should run successfully.