feat(linter): add typescript/prefer-readonly rule by camc314 · Pull Request #19446 · oxc-project/oxc

camc314 · 2026-02-16T17:16:15Z

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camc314 · 2026-02-16T17:16:35Z

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codspeed-hq · 2026-02-16T17:29:44Z

Merging this PR will not alter performance

✅ 22 untouched benchmarks
⏩ 28 skipped benchmarks¹

_{Comparing c/02-14-feat_linter_add_typescript_prefer-readonly_rule (71d8179) with c/02-14-feat_linter_add_typescript_no-unnecessary-qualifier_rule (09cbfbb)²}

28 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩
No successful run was found on c/02-14-feat_linter_add_typescript_no-unnecessary-qualifier_rule (9b17d44) during the generation of this report, so 4d617ba was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

camc314 · 2026-02-16T19:24:14Z

Merge activity

Feb 16, 7:24 PM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Feb 16, 7:36 PM UTC: camc314 added this pull request to the Graphite merge queue.
Feb 16, 7:45 PM UTC: Merged by the Graphite merge queue.

Copilot

Pull request overview

Adds support for the TypeScript ESLint prefer-readonly rule to the linter’s TypeScript (tsgolint/type-aware) rule set, including configuration schema wiring and fixture/snapshot coverage.

Changes:

Introduces a new typescript/prefer-readonly rule definition with onlyInlineLambdas configuration support.
Registers the rule in the TypeScript rules module list and generated rule enum/runner plumbing.
Adds/updates fixtures and snapshots to exercise the rule in both the base tsgolint suite and the rule-options suite.

Reviewed changes

Copilot reviewed 11 out of 13 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
crates/oxc_linter/src/rules/typescript/prefer_readonly.rs	New rule definition + config schema/serialization for tsgolint integration.
crates/oxc_linter/src/rules.rs	Exposes the new `prefer_readonly` module under the TypeScript rules namespace.
crates/oxc_linter/src/generated/rules_enum.rs	Adds the rule to the generated enum, IDs, dispatch, config schema plumbing, and RULES list.
crates/oxc_linter/src/generated/rule_runner_impls.rs	Registers a `RuleRunner` impl for the new rule (consistent with other tsgolint rules).
apps/oxlint/src/snapshots/fixtures__tsgolint_rule_options_--type-aware@oxlint.snap	Updates snapshot output to include the new rule’s diagnostic and updated counts.
apps/oxlint/src/snapshots/fixtures__tsgolint_--type-aware@oxlint.snap	Updates snapshot output to include the new rule’s diagnostic and updated counts.
apps/oxlint/fixtures/tsgolint_rule_options/test.ts	Adds a fixture case for `onlyInlineLambdas`.
apps/oxlint/fixtures/tsgolint_rule_options/.oxlintrc.json	Enables `typescript/prefer-readonly` with `onlyInlineLambdas: true` for the options fixture suite.
apps/oxlint/fixtures/tsgolint/prefer-readonly.ts	Adds a dedicated fixture file for the rule.
apps/oxlint/fixtures/tsgolint/.oxlintrc.json	Enables `typescript/prefer-readonly` in the tsgolint fixture suite.

# Oxlint ### 💥 BREAKING CHANGES - 4315594 oxlint: [**BREAKING**] Deprecate `"always"` and `"as-needed"` options of the radix rule (#19408) (Sysix) - d4c7af3 linter: [**BREAKING**] Remove `allowRuleToRunWithoutStrictNullChecksIKnowWhatIAmDoing` option (#19451) (camc314) ### 🚀 Features - 82ca5c3 linter: Add typescript/dot-notation rule (#19442) (camc314) - 6db0811 linter: Implement eslint-plugin-vitest/no-importing-vitest-globals (#18694) (Said Atrahouch) - c7fe8ae linter: Implement eslint-plugin-vitest/prefer-import-in-mock (#17966) (Said Atrahouch) - 0abb39a linter: Implement eslint-vitest-jest-plugin/prefer-mock-return-shorthand (#18002) (Said Atrahouch) - 2b95537 linter: Implement `n/no-path-concat` rule (#19502) (Mikhail Baev) - 735d0e4 linter: Implement typescript/no-useless-default-assignment (#19488) (camc314) - 31c3a93 linter: Add typescript/no-unnecessary-type-parameters rule (#19450) (camc314) - c948090 linter: Add typescript/consistent-return rule (#19449) (camc314) - 9f87df0 linter: Add typescript/prefer-string-starts-ends-with rule (#19448) (camc314) - 04536be linter: Add typescript/prefer-regexp-exec rule (#19447) (camc314) - 56a7feb linter: Add typescript/prefer-readonly rule (#19446) (camc314) - a1cea63 linter: Add typescript/no-unnecessary-qualifier rule (#19445) (camc314) - e3144d2 linter: Add typescript/prefer-find rule (#19444) (camc314) - 13c7408 linter: Add typescript/prefer-readonly-parameter-types rule (#19443) (camc314) - 9b17d44 linter: Add typescript/strict-void-return rule (#19441) (camc314) - ed821b4 linter: Add typescript/consistent-type-exports rule (#19440) (camc314) ### 🐛 Bug Fixes - daad7bc linter/array-callback-return: Check `allowVoid` option (#19506) (Said Atrahouch) - 638cf94 linter: Add help text to eslint rule diagnostics (#19508) (Kyle Tse) - 79fc6d7 linter: Move no-use-before-define to eslint plugin (#19438) (camc314) - c832a9f linter: Add `onScrollEnd` and `onScrollEndCapture` to `react/no-unknown-property`. (#19536) (connorshea) - 999a0db linter: Add help text to `symbol-description` diagnostics (#19538) (Anthony Amaro) - f064482 linter: Add help text to eslint rule diagnostics (#19539) (Anthony Amaro) - fd11073 linter/react/no-unknown-property: Add missing `fetchPriority` prop (#19525) (João Pedro Schmitz) - a9bb604 linter/no-shadow: Align initializer shadow handling with typescript-eslint (#19462) (camc314) - 32e6eb9 linter: Handle typed arrays/array buffers in `prefer-spread` rule. (#19478) (connorshea) - e309f84 linter: Handle additional cases in `typescript/consistent-generic-constructors` rule. (#19477) (connorshea) - 71db91a linter/array-callback-return: Check `fromAsync`, update test cases (#19483) (Said Atrahouch) - 2a12d74 linter: Handle optional chaining in `no-array-method-this-argument` rule. (#19476) (connorshea) - f65310b linter: Handle optional chaining in `prefer-object-from-entries` rule. (#19475) (connorshea) - 840acf4 linter: Handle optional chain in `no-unnecessary-array-flat-depth` rule. (#19471) (connorshea) - 85a19e9 linter: Skip string literal imports in `consistent-assert` rule. (#19474) (connorshea) ### ⚡ Performance - 6155ac4 linter/constructor-super: Use node_id over nodes loop (#19489) (camc314) - a02496d linter/consistent-index-object-style: Resolve circular type refs semantically (#19490) (camc314) # Oxfmt ### 🚀 Features - 652c346 oxfmt/lsp: Support `untitled://` schema (#19287) (Sysix) ### 🐛 Bug Fixes - 6c61b70 oxfmt: Fix outdated `sortImports.groups` doc comments (#19513) (leaysgur) Co-authored-by: camc314 <18101008+camc314@users.noreply.github.com>

github-actions bot added A-linter Area - Linter A-cli Area - CLI C-enhancement Category - New feature or request labels Feb 16, 2026

camc314 self-assigned this Feb 16, 2026

camc314 force-pushed the c/02-14-feat_linter_add_typescript_prefer-readonly_rule branch from a405c01 to 4ea2e55 Compare February 16, 2026 19:19

camc314 force-pushed the c/02-14-feat_linter_add_typescript_no-unnecessary-qualifier_rule branch from 7b778d5 to 405e629 Compare February 16, 2026 19:19

camc314 force-pushed the c/02-14-feat_linter_add_typescript_prefer-readonly_rule branch from 4ea2e55 to c740bcf Compare February 16, 2026 19:21

camc314 force-pushed the c/02-14-feat_linter_add_typescript_no-unnecessary-qualifier_rule branch from 405e629 to 09cbfbb Compare February 16, 2026 19:21

camc314 force-pushed the c/02-14-feat_linter_add_typescript_prefer-readonly_rule branch from c740bcf to 71d8179 Compare February 16, 2026 19:23

camc314 marked this pull request as ready for review February 16, 2026 19:24

Copilot AI review requested due to automatic review settings February 16, 2026 19:24

camc314 added the 0-merge Merge with Graphite Merge Queue label Feb 16, 2026

Copilot started reviewing on behalf of camc314 February 16, 2026 19:25 View session

Copilot AI reviewed Feb 16, 2026

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camc314 force-pushed the c/02-14-feat_linter_add_typescript_no-unnecessary-qualifier_rule branch from 09cbfbb to 919f836 Compare February 16, 2026 19:30

camc314 force-pushed the c/02-14-feat_linter_add_typescript_prefer-readonly_rule branch from 71d8179 to 619fecc Compare February 16, 2026 19:30

feat(linter): add typescript/prefer-readonly rule (#19446)

56a7feb

graphite-app bot force-pushed the c/02-14-feat_linter_add_typescript_no-unnecessary-qualifier_rule branch from 919f836 to a1cea63 Compare February 16, 2026 19:37

graphite-app bot force-pushed the c/02-14-feat_linter_add_typescript_prefer-readonly_rule branch from 619fecc to 56a7feb Compare February 16, 2026 19:38

graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Feb 16, 2026

Base automatically changed from c/02-14-feat_linter_add_typescript_no-unnecessary-qualifier_rule to main February 16, 2026 19:44

graphite-app bot merged commit 56a7feb into main Feb 16, 2026
22 checks passed

graphite-app bot deleted the c/02-14-feat_linter_add_typescript_prefer-readonly_rule branch February 16, 2026 19:45

Boshen mentioned this pull request Feb 19, 2026

release(apps): oxlint v1.49.0 && oxfmt v0.34.0 #19553

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feat(linter): add typescript/prefer-readonly rule#19446

feat(linter): add typescript/prefer-readonly rule#19446
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