feat(eslint-plugin): [no-misused-promises] warn when spreading promises

[papermana]

PR Checklist

• Addresses an existing open issue: fixes Enhancement: [no-misused-promises] Warn when spreading a promise #5049
• That issue was marked as accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

This PR adds a new option for no-misused-promises, turned on by default. It will show an error if the code spreads a non-awaited promise (which is almost certainly unintended).

Object.assign could also be supported as an improvement.

[typescript-eslint]

Thanks for the PR, @papermana!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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✅ Successfully ran 47 targets

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[codecov]

Codecov Report

Merging #5053 (b41256c) into main (bc90ce0) will increase coverage by 2.27%.
The diff coverage is 100.00%.

❗ Current head b41256c differs from pull request most recent head f390959. Consider uploading reports for the commit f390959 to get more accurate results

@@            Coverage Diff             @@
##             main    #5053      +/-   ##
==========================================
+ Coverage   91.53%   93.80%   +2.27%     
==========================================
  Files         343      286      -57     
  Lines       10750     9815     -935     
  Branches     3147     2936     -211     
==========================================
- Hits         9840     9207     -633     
+ Misses        588      328     -260     
+ Partials      322      280      -42     

Flag	Coverage Δ
unittest	93.80% <100.00%> (+2.27%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ges/eslint-plugin/src/rules/no-misused-promises.ts	98.35% <100.00%> (+0.09%)	⬆️
packages/eslint-plugin/src/util/misc.ts	94.00% <0.00%> (-2.43%)	⬇️
packages/utils/src/json-schema.ts
packages/utils/src/ts-eslint/index.ts
packages/utils/src/eslint-utils/nullThrows.ts
packages/type-utils/src/predicates.ts
packages/type-utils/src/isUnsafeAssignment.ts
packages/type-utils/src/getTypeArguments.ts
packages/type-utils/src/typeFlagUtils.ts
packages/utils/src/ast-utils/misc.ts
... and 49 more

[JoshuaKGoldberg]

Looks great so far. Thanks for sending this in! Just requesting changes to get a bit more test coverage, particularly around array spreads.

[JoshuaKGoldberg]

Fantastic, thanks @papermana! 🙌