fix: prevent deadlock on single-core systems and with empty arrays in utils/parallel

[shiavm006]

Description

What is the purpose of this pull request?

This pull request:

fixes a deadlock bug in @stdlib/utils/parallel where the function would hang indefinitely on single-core systems (numCPUs = 1) because defaults would set workers = 0. a deadlock bug when called with empty arrays (parallel([])) where clamping logic would reduce workers to 0.
fixes a deadlock bug when explicitly passing {workers: 0, concurrency: 0} options and updated defaults.js to use @stdlib/math/base/special/fast/max to ensure minimum of 1 worker/concurrency as suggested by maintainer ,adds safeguard in main.js to prevent workers/concurrency from dropping below 1 after clamping logic , tests covering all three edge cases.

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

• No related issue (discussed with maintainer @kgryte via direct message)

Questions

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No.

Other

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This fix was discussed with maintainer @kgryte who suggested using @stdlib/math/base/special/fast/max for the defaults.js fix. The safeguard in main.js was added to handle edge cases where clamping could still result in 0 workers even with the defaults fix.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the [contributing guidelines][contributing].

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@stdlib-js/reviewers
[contributing]: https://github.com/stdlib-js/stdlib/blob/develop/CONTRIBUTING.md

[shiavm006]

cc @kgryte i verified it locally ya u can check it out like can disscuss on changes and implement that same

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
utils/parallel	$\color{green}1363/1363$ $\color{green}+0.00%$	$\color{red}148/149$ $\color{green}+0.00%$	$\color{green}35/35$ $\color{green}+0.00%$	$\color{green}1363/1363$ $\color{green}+0.00%$

The above coverage report was generated for the changes in this PR.

[shiavm006]

@kgryte what u think about it

[kgryte]

LGTM