chore: migrate eslint 9 → 10

[Snoww3d]

Context

Dependabot PR #340 bumps eslint from 9.39.2 to 10.0.0 but CI fails (frontend tests, lint, and Docker build all broken).

What needs to happen

ESLint 10 is a major version with breaking changes. Likely needs:

• Config format updates (eslint.config.js)
• Plugin compatibility checks (@typescript-eslint, react-refresh)
• Potential rule API changes

References

• Dependabot PR: chore(deps-dev): bump eslint from 9.39.2 to 10.0.0 in /frontend/jwst-frontend #340
• ESLint 10 migration guide

[Snoww3d]

Status Update — Feb 2026

eslint 10 migration is blocked by eslint-plugin-react.

What happened

• Dependabot opened PR chore(deps-dev): bump eslint from 9.39.2 to 10.0.1 in /frontend/jwst-frontend #418 for eslint 9→10
• Investigation found that eslint-plugin-react@7.37.5 (latest) has a runtime crash with eslint 10 — it calls context.getFilename() which was removed (now context.filename)
• This isn't a workaround-able deprecation warning — the plugin literally crashes on load
• PR chore(deps-dev): bump eslint from 9.39.2 to 10.0.1 in /frontend/jwst-frontend #418 has been closed

Upstream tracking

• ESLint v10 compatibility jsx-eslint/eslint-plugin-react#3977

What we did do

• Merged PR chore: bump eslint-plugin-react-hooks from 5.2.0 to 7.0.1 #414: bumped eslint-plugin-react-hooks from 5.2.0 → 7.0.1 (works fine with eslint 9)

Next steps

• Monitor the upstream issue for a compatible eslint-plugin-react release
• Once available, reopen eslint 10 migration

[Snoww3d]

Deep Research — ESLint 10 Ecosystem Readiness (Feb 22, 2026)

Our plugin stack vs ESLint 10

Plugin	Our Version	ESLint 10?	Details
@eslint/js	^9.17.0	✅ Yes	Part of eslint core
@typescript-eslint/*	^8.56.0	✅ Yes	PR #12057 merged Feb 13
eslint-plugin-react	^7.37.2	❌ Crashes	PR #3979 open, under review, no timeline
eslint-plugin-react-hooks	^7.0.1	⚠️ Runtime OK, peerDep wrong	PR #35720 merged Feb 13, awaiting npm publish
eslint-plugin-react-refresh	^0.5.0	❓ Unknown	No tracking issue found

Why eslint-plugin-react crashes

ESLint 10 removed deprecated context methods (context.getFilename() → context.filename, context.getSourceCode() → context.sourceCode, etc.). The plugin uses context.getFilename() in its internal version detection utility — not in rule create() functions — so the @eslint/compat fixupPluginRules() shim does not fix it.

Maintainer position (ljharb, Feb 7): "we're explicitly not compatible with eslint 10. until the peer dep range is updated, one should not attempt to use eslint 10 with this plugin"

PR #3979 is open with change requests. No merge timeline.

ESLint 10 itself

Primarily a cleanup release — removes APIs deprecated in v9, drops legacy .eslintrc config entirely. No must-have new features. ESLint 9 continues active maintenance (v9.39.x, Feb 2026).

Two paths forward

Path A: Wait (current plan) — Stay on eslint 9. Monitor upstream. Zero effort, zero risk.

Path B: Replace eslint-plugin-react with @eslint-react/eslint-plugin — A modern rewrite (v2.12.0+ supports eslint 10, 4-7x faster, actively maintained). Requires eslint config rewrite since rule names differ. Unblocks eslint 10 without waiting on upstream.

Upstream issues to monitor

• eslint-plugin-react #3977 — tracking issue
• eslint-plugin-react PR #3979 — fix PR (open, change requests)
• eslint-plugin-react-hooks PR #35720 — peerDep fix (merged, awaiting npm publish)
• typescript-eslint PR #12057 — eslint 10 support (merged)