feat(build-tools): migrate to ESLint 9 flat config with shared eslint-config-fluid #26150
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- Upgrade ESLint from 8.57.0 to 9.18.0 - Upgrade typescript-eslint from v6 to v8.20.0 - Add @eslint/js and eslint-config-prettier v10 - Remove @fluidframework/eslint-config-fluid dependency - Remove eslint-config-oclif and eslint-config-oclif-typescript Create shared base configuration (eslint.config.base.mjs) at workspace root with reusable building blocks for all packages. Migrate all 5 packages from .eslintrc.cjs to eslint.config.mjs: - build-tools - build-infrastructure - build-cli - version-tools - bundle-size-tools Clean up obsolete eslint-disable directives for rules that no longer exist (import-x/*, tsdoc/syntax, n/no-process-exit, @rushstack/*).
Move all ESLint-related dependencies to the workspace root package.json and enhance the shared base config with plugin configurations: - Remove duplicate eslint, typescript-eslint, @eslint/js, and eslint-config-prettier from all package devDependencies - Add eslint-plugin-jsdoc, eslint-plugin-unicorn, and eslint-plugin-chai-friendly to root - Add pnpm override to force ESLint 9.x (jssm-viz-cli brings in 8.x) - Enhance eslint.config.base.mjs with jsdocConfig, unicornConfig, and chaiFriendlyConfig exports - Update createConfig() with optional jsdoc and unicorn flags - Simplify build-cli config from 107 to 30 lines using createConfig() - Update build-infrastructure to use shared chaiFriendlyConfig Net reduction of 262 lines across configs and lockfile.
Signed-off-by: Tyler Butler <tylerbu@microsoft.com>
Rename ESLint flat config files from JavaScript (.mjs) to TypeScript (.mts) for consistency with PR microsoft#26070. Add jiti dependency to enable runtime transpilation of TypeScript config files. Also includes the ESLint 9 flat config detection fix from PR microsoft#26147.
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Pull request overview
This pull request migrates the build-tools repository from ESLint 8 to ESLint 9 with the new flat config format. The changes include:
- Upgrading ESLint from 8.57.0 to 9.39.2 and typescript-eslint from v6 to v8.52.0
- Adding new ESLint-related dependencies (@eslint/js, eslint-config-prettier v10, eslint-plugin-jsdoc, eslint-plugin-unicorn, eslint-plugin-chai-friendly)
- Removing deprecated packages (@fluidframework/eslint-config-fluid, eslint-config-oclif, eslint-config-oclif-typescript)
- Creating a shared base configuration (eslint.config.base.mts) and migrating all packages to eslint.config.mts
- Consolidating ESLint dependencies to the workspace root
- Cleaning up obsolete eslint-disable directives
Reviewed changes
Copilot reviewed 151 out of 152 changed files in this pull request and generated 1 comment.
Show a summary per file
| File | Description |
|---|---|
| build-tools/pnpm-lock.yaml | Updated dependencies: ESLint 9.39.2, typescript-eslint 8.52.0, added new plugins, removed deprecated configs |
| build-tools/packages/*/package.json | Removed individual ESLint dependencies, updated build-tools-bin versions |
| build-tools/packages/*/.eslintrc.cjs | Deleted legacy ESLint configuration files |
| build-tools/packages/*/eslint.config.mts | Added new flat config files for each package |
| build-tools/packages//src/**/.ts | Removed obsolete eslint-disable comments, fixed unused variable patterns |
| build-tools/packages/build-tools/src/fluidBuild/tasks/taskUtils.ts | Updated to detect both ESLint 9 flat config and legacy eslintrc files |
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Remove disabled rules from jsdoc, unicorn, and import-x configs to enable stricter linting. Only unicorn/prevent-abbreviations and unicorn/filename-case remain disabled as they require extensive codebase changes. Rules now enabled: - jsdoc: require-jsdoc, require-param, require-returns, check-param-names, tag-lines - unicorn: no-null, no-array-for-each, prefer-string-replace-all, no-array-reduce, prefer-at, prefer-top-level-await, switch-case-braces, no-useless-undefined, prefer-ternary, no-process-exit, import-style, prefer-type-error, no-array-push-push, no-nested-ternary, consistent-function-scoping, prefer-string-raw, consistent-existence-index-check, consistent-destructuring, no-await-expression-member - import-x: no-named-as-default-member, no-default-export
Fix low-count ESLint violations across the build-tools workspace: - Replace .replace(/x/g, ...) with .replaceAll() (unicorn/prefer-string-replace-all) - Change import * as path to import path (unicorn/import-style) - Remove useless undefined arguments (unicorn/no-useless-undefined) - Fix JSDoc @param names to match actual parameters (jsdoc/check-param-names) - Add inline disables for idiomatic usage patterns: - async.mapLimit, semver.parse, sortJson.overwrite (import-x/no-named-as-default-member) - prompts default export (import-x/no-named-as-default) - Remove unused eslint-disable directives for import-x/no-default-export - Change @module to @packageDocumentation for TSDoc compatibility (tsdoc/syntax)
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build-tools/packages/build-cli/src/commands/publish/tarballs.ts
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…at config Simplify build-tools ESLint configuration by importing from the shared @fluidframework/eslint-config-fluid package's flat.mts module. Changes: - Add eslint-config-fluid to the build-tools pnpm workspace - Rewrite eslint.config.base.mts to import minimalDeprecated from shared config - Simplify per-package ESLint configs to spread baseConfig with overrides - Add syncpack rules to ignore eslint-config-fluid's version policies - Disable stricter rules from shared config that require code changes The shared config provides consistent linting rules across the Fluid Framework monorepo. Build-tools-specific overrides are applied for rules that don't apply to internal tooling packages.
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The eslint-config-fluid package was appearing twice in workspace enumeration because it was listed in both the root and build-tools pnpm-workspace.yaml files. Changes: - Remove eslint-config-fluid from build-tools/pnpm-workspace.yaml - Use link: protocol instead of workspace:* for eslint-config-fluid dependency - Add eslint as devDependency to build-tools packages (policy requirement) - Add common/build/ directory to Build layer in layerInfo.json
Add ignore rules for eslint-config-fluid package and dependency in both semverGroups and versionGroups. The package is maintained in the parent workspace and uses link: protocol for cross-workspace reference.
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Summary
Migrate build-tools to ESLint 9 flat config format, using the shared
@fluidframework/eslint-config-fluidpackage for consistent linting rules across the Fluid Framework monorepo.Key Changes
ESLint 9 Migration:
.eslintrc.cjstoeslint.config.mtsflat config formatShared Configuration:
@fluidframework/eslint-config-fluidto the build-tools workspaceminimalDeprecatedconfig from the sharedflat.mtsmoduleeslint.config.base.mtsthat extends shared config with build-tools-specific overridesBuild-tools Overrides:
Infrastructure: