[no-misused-promises] checksVoidReturn=true doesn't catch the error when variadic arguments are used (like `...handlers: Array<() => void>`) #4015

dko-slapdash · 2021-10-16T00:07:39Z

This issue affects e.g. express used with new route handlers which are required to be non-async in their TS typings. I think in case of variadic arguments, the plugin verifies just the 1st argument and, if it's okay, doesn't even check the rest of the arguments.

I have tried restarting my IDE and the issue persists.
I have updated to the latest version of the packages.
I have read the FAQ and my problem is not listed.

Repro

{
  "rules": {
     "@typescript-eslint/no-misused-promises": "error",
  }
}

function get2(_h1: () => void, _h2: () => void) {}

function get(..._handlers: Array<() => void>) {}

get2(
  () => {},
  async () => {} // <-- fails, which is what we want
);

get(
  () => {},
  async () => {}  // <-- this must fail too, but it does not
);

Expected Result

Both get() and get2() calls must raise an eslint error.

Actual Result

Only get2() is treated as incorrect, and get() is fine - although it should fail too:

Additional Info

Versions

package	version
`@typescript-eslint/eslint-plugin`	`5.0.0`
`@typescript-eslint/parser`	`5.0.0`
`TypeScript`	`4.4.4`
`ESLint`	`8.0.1`
`node`	`16.11.1`

The text was updated successfully, but these errors were encountered:

dko-slapdash · 2021-10-16T01:22:16Z

Here is BTW what I have to do to work-around this eslint issue with variadic parameters:

(Originally in express-serve-static-core, they're defined as methods with variadic ...handlers: Array<RequestHandler<P, ResBody, ReqBody, ReqQuery, Locals>>).

This allows to write something like

import asyncHandler from "express-async-handler";
...
app.get(
  AppRoutes.connectApp.pattern,
  asyncHandler(requireAuth),
  asyncHandler(connectAppRoute)
);

and have peace in mind that, if we accidentally forget asyncHandler wrapper for connectAppRoute, no-misused-promises will warn us.

Fixes typescript-eslint#4015 This extends 'no-misued-promises' with support for checking variadic arguments passed to a 'rest' parameter. If a function is declared with an argument like '...handlers: Array<() => void>', we now check if the type argument to `Array` is a void-returning function, and if so, check if any of the variadic arguments return a Promise.

…5731) * feat(eslint-plugin): Check 'rest' parameters in no-misused-promises Fixes #4015 This extends 'no-misued-promises' with support for checking variadic arguments passed to a 'rest' parameter. If a function is declared with an argument like '...handlers: Array<() => void>', we now check if the type argument to `Array` is a void-returning function, and if so, check if any of the variadic arguments return a Promise. * Address review comments * Fix spelling * Address additional review comments * nit: split up tests a bit, and add comments about () Co-authored-by: Josh Goldberg <git@joshuakgoldberg.com>

This PR contains the following updates: | Package | Type | Update | Change | |---|---|---|---| | [@typescript-eslint/eslint-plugin](https://github.com/typescript-eslint/typescript-eslint) | devDependencies | minor | [`5.39.0` -> `5.40.0`](https://renovatebot.com/diffs/npm/@typescript-eslint%2feslint-plugin/5.39.0/5.40.0) | | [@typescript-eslint/parser](https://github.com/typescript-eslint/typescript-eslint) | devDependencies | minor | [`5.39.0` -> `5.40.0`](https://renovatebot.com/diffs/npm/@typescript-eslint%2fparser/5.39.0/5.40.0) | --- ### Release Notes <details> <summary>typescript-eslint/typescript-eslint (@typescript-eslint/eslint-plugin)</summary> ### [`v5.40.0`](https://github.com/typescript-eslint/typescript-eslint/blob/HEAD/packages/eslint-plugin/CHANGELOG.md#5400-httpsgithubcomtypescript-eslinttypescript-eslintcomparev5390v5400-2022-10-10) [Compare Source](typescript-eslint/typescript-eslint@v5.39.0...v5.40.0) ##### Bug Fixes - **eslint-plugin:** \[consistent-indexed-object-style] handle interface generic ([#5746](typescript-eslint/typescript-eslint#5746)) ([7a8a0a3](typescript-eslint/typescript-eslint@7a8a0a3)) - **eslint-plugin:** \[no-unnecessary-condition] handle void ([#5766](typescript-eslint/typescript-eslint#5766)) ([ac8f06b](typescript-eslint/typescript-eslint@ac8f06b)) ##### Features - **eslint-plugin:** Check 'rest' parameters in no-misused-promises ([#5731](typescript-eslint/typescript-eslint#5731)) ([6477f38](typescript-eslint/typescript-eslint@6477f38)), closes [#4015](typescript-eslint/typescript-eslint#4015) - **utils:** add dependency constraint filtering for `RuleTester` ([#5750](typescript-eslint/typescript-eslint#5750)) ([121f4c0](typescript-eslint/typescript-eslint@121f4c0)) </details> <details> <summary>typescript-eslint/typescript-eslint (@typescript-eslint/parser)</summary> ### [`v5.40.0`](https://github.com/typescript-eslint/typescript-eslint/blob/HEAD/packages/parser/CHANGELOG.md#5400-httpsgithubcomtypescript-eslinttypescript-eslintcomparev5390v5400-2022-10-10) [Compare Source](typescript-eslint/typescript-eslint@v5.39.0...v5.40.0) **Note:** Version bump only for package [@typescript-eslint/parser](https://github.com/typescript-eslint/parser) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about these updates again. --- - [ ] If you want to rebase/retry this PR, click this checkbox. --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Co-authored-by: cabr2-bot <cabr2.help@gmail.com> Reviewed-on: https://codeberg.org/Calciumdibromid/CaBr2/pulls/1580 Reviewed-by: Epsilon_02 <epsilon_02@noreply.codeberg.org> Co-authored-by: Calciumdibromid Bot <cabr2_bot@noreply.codeberg.org> Co-committed-by: Calciumdibromid Bot <cabr2_bot@noreply.codeberg.org>

dko-slapdash added package: eslint-plugin-tslint Issues related to @typescript-eslint/eslint-plugin-tslint triage Waiting for team members to take a look labels Oct 16, 2021

dko-slapdash mentioned this issue Oct 16, 2021

Is this library needed when using express-async-handler or express-async-router? davidbanham/express-async-errors#36

Closed

bradzacher added bug Something isn't working package: eslint-plugin Issues related to @typescript-eslint/eslint-plugin and removed package: eslint-plugin-tslint Issues related to @typescript-eslint/eslint-plugin-tslint triage Waiting for team members to take a look labels Oct 18, 2021

JoshuaKGoldberg added the accepting prs Go ahead, send a pull request that resolves this issue label Oct 25, 2021

bradzacher mentioned this issue Feb 7, 2022

[no-misused-promises] Suggestion: check more AST positions #4523

Closed

3 tasks

Aaron1011 mentioned this issue Oct 3, 2022

feat(eslint-plugin): Check 'rest' parameters in no-misused-promises #5731

Merged

3 tasks

JoshuaKGoldberg closed this as completed in #5731 Oct 7, 2022

sync-by-unito bot mentioned this issue Oct 17, 2022

build(deps-dev): bump @typescript-eslint/eslint-plugin from 5.30.6 to 5.40.0 SmartTokenLabs/token-negotiator#424

Merged

sync-by-unito bot mentioned this issue Oct 25, 2022

build(deps-dev): bump @typescript-eslint/eslint-plugin from 5.36.1 to 5.41.0 numbersprotocol/capture-lite#2211

Closed

sync-by-unito bot mentioned this issue Nov 1, 2022

build(deps-dev): bump @typescript-eslint/eslint-plugin from 5.36.1 to 5.42.0 numbersprotocol/capture-lite#2265

Closed

github-actions bot locked as resolved and limited conversation to collaborators Nov 7, 2022

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

[no-misused-promises] checksVoidReturn=true doesn't catch the error when variadic arguments are used (like `...handlers: Array<() => void>`) #4015

[no-misused-promises] checksVoidReturn=true doesn't catch the error when variadic arguments are used (like `...handlers: Array<() => void>`) #4015

dko-slapdash commented Oct 16, 2021 •

edited

Loading

dko-slapdash commented Oct 16, 2021 •

edited

Loading

[no-misused-promises] checksVoidReturn=true doesn't catch the error when variadic arguments are used (like ...handlers: Array<() => void>) #4015

[no-misused-promises] checksVoidReturn=true doesn't catch the error when variadic arguments are used (like ...handlers: Array<() => void>) #4015

Comments

dko-slapdash commented Oct 16, 2021 • edited Loading

dko-slapdash commented Oct 16, 2021 • edited Loading

[no-misused-promises] checksVoidReturn=true doesn't catch the error when variadic arguments are used (like `...handlers: Array<() => void>`) #4015

[no-misused-promises] checksVoidReturn=true doesn't catch the error when variadic arguments are used (like `...handlers: Array<() => void>`) #4015

dko-slapdash commented Oct 16, 2021 •

edited

Loading

dko-slapdash commented Oct 16, 2021 •

edited

Loading