chore: Enable @typescript-eslint/no-explicit-any as an error rule

[MajorLift]

Description

The ongoing TypeScript conversion effort will be most effective if any usage can be minimized in incoming code. A helpful step in achieving this is to enable @typescript-eslint/no-explicit-any as an error rule.

To minimize disruption to existing code, all 385 existing violations have been annotated with an eslint-disable-next-line directive and TODO comment. Errors for this rule will only be triggered by new instances of any.

This approach has previously been successfully applied to the core monorepo.

Disclaimer

This is a major change, so please feel free to voice any concerns. Code review and updates to documentation may be sufficient to encourage best practices for the time being.

That said, if minimizing any usage through these other means sounds like a good idea, that might be a strong sign that enabling this linter rule aligns with the coding standards that we already have in place.

Related issues

• Closes style: Enable @typescript-eslint/no-explicit-any as an error rule #23530

Manual testing steps

Screenshots/Recordings

Pre-merge author checklist

• I’ve followed MetaMask Coding Standards.
• I've clearly explained what problem this PR is solving and how it is solved.
• I've linked related issues
• I've included manual testing steps
• I've included screenshots/recordings if applicable
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.
• I’ve properly set the pull request status:
  • In case it's not yet "ready for review", I've set it to "draft".
  • In case it's "ready for review", I've changed it from "draft" to "non-draft".

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.13%. Comparing base (d405dcc) to head (2976bca).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop   #23531   +/-   ##
========================================
  Coverage    69.13%   69.13%           
========================================
  Files         1160     1160           
  Lines        44260    44260           
  Branches     11839    11839           
========================================
  Hits         30596    30596           
  Misses       13664    13664           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[brad-decker]

@Gudahtt / @mcmire / @davidmurdoch is this how you would suggest handling enabling this rule to prevent future breaks? My concern is the TODO's will get lost. Though the only alternative I know is to ignore rules by file.

[mcmire]

@brad-decker Sure, good question.

The motivation for enabling this rule is to prevent further uses of any, which (despite the name) completely disables typechecking for the variable in question. We noticed that we had a lot of instances of any on core, and the approach we took to solve it was to add eslint-disable lines. Then, we did a search to count the number of instances of the TODO: Replace `any` with type comment across the project per file. We grouped files by area and then created a ticket on our Zenhub board for each area. Since then we've been working through those tickets to replace any with a better type and remove the eslint-disable comments.

This approach has worked for us, but if there is another approach that you think would work for you, we can certainly follow it.

[metamaskbot]

Builds ready [2976bca]

• builds: chrome, firefox
• builds (beta): chrome
• builds (flask): chrome, firefox
• builds (MMI): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• mv3: Background Module Init Stats
• mv3: UI Init Stats
• mv3: Module Load Stats
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• code coverage: Report
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5
  • common: 0, 1, 2, 3, 4, 5, 6
  • content-script: 0
  • contentscript: contentscript
  • disable-console: disable-console
  • policy-load: policy-load
  • sentry-install: sentry-install
  • ui: 0, 1, 10, 11, 12, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (952 ± 504 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	78	230	137	48	23
		domContentLoaded	16	104	42	26	13
		load	55	2651	952	1049	504
		domInteractive	16	104	42	26	13

Bundle size diffs [🚨 Warning! Bundle size has increased!]

• background: 29 Bytes (0.00%)
• ui: 0 Bytes (0.00%)
• common: 0 Bytes (0.00%)