chore(eslint): add md and mdx language block linting

[paulpopus]

Adds a new custom linting rule in .md and .mdx files so that code blocks can only use languages supported by our prism renderer.

We need this because if you put for example csv as a language, it will be allowed to be committed without errors or warnings but it will crash building the website effectively blocking new deployments.

Here it is in action:

Screen.Recording.2026-01-21.at.15.34.07.mov

[Copilot]

Pull request overview

This PR introduces custom ESLint linting for code blocks in Markdown and MDX documentation files to prevent build failures caused by unsupported syntax highlighting languages.

Changes:

• Adds a new ESLint rule valid-code-block-languages that validates code fence language identifiers against a whitelist of supported languages
• Creates a minimal text parser for MDX/MD files to enable ESLint processing without requiring full AST parsing
• Configures ESLint to validate docs/**/*.mdx and docs/**/*.md files with the new rule

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
packages/eslint-plugin/index.mjs	Registers the new valid-code-block-languages rule in the plugin exports
packages/eslint-plugin/customRules/valid-code-block-languages.js	Implements the code block language validation rule with supported language whitelist and auto-fix for known unsupported languages
packages/eslint-plugin/customRules/mdx-text-parser.js	Provides a minimal ESLint parser that treats MDX/MD files as plain text for linting purposes
eslint.config.js	Configures ESLint to apply the new rule to documentation files using the custom parser
.vscode/settings.json	Enables ESLint validation for MDX and Markdown files in VS Code

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[github-actions]

📦 esbuild Bundle Analysis for payload

This analysis was generated by esbuild-bundle-analyzer. 🤖

Meta File	Out File	Size (raw)	Note
packages/next/meta_index.json	esbuild/index.js	950.34 KB	🆕 Added
packages/payload/meta_index.json	esbuild/index.js	1.32 MB	🆕 Added
packages/payload/meta_shared.json	esbuild/exports/shared.js	168.53 KB	🆕 Added
packages/richtext-lexical/meta_client.json	esbuild/exports/client_optimized/index.js	281.79 KB	🆕 Added
packages/ui/meta_client.json	esbuild/exports/client_optimized/index.js	1.17 MB	🆕 Added
packages/ui/meta_shared.json	esbuild/exports/shared_optimized/index.js	16.32 KB	🆕 Added

Largest paths

These visualization shows top 20 largest paths in the bundle.

Meta file: packages/next/meta_index.json, Out file: esbuild/index.js

Path	Size
../../node_modules	${{\color{Goldenrod}{ ████████████████████▌ }}}$ 82.4%, 779.13 KB
dist/views/Version	${{\color{Goldenrod}{ █▎ }}}$ 5.4%, 51.27 KB
dist/views/Dashboard	${{\color{Goldenrod}{ ▍ }}}$ 1.8%, 17.16 KB
dist/views/Document	${{\color{Goldenrod}{ ▍ }}}$ 1.7%, 16.18 KB
dist/views/List	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 11.28 KB
dist/views/Root	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 9.03 KB
dist/views/Versions	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 6.16 KB
dist/views/API	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 6.08 KB
dist/elements/Nav	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 5.96 KB
dist/views/Account	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 5.46 KB
dist/elements/DocumentHeader	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 4.81 KB
dist/views/Login	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 4.40 KB
dist/views/ForgotPassword	${{\color{Goldenrod}{ }}}$ 0.3%, 3.09 KB
dist/layouts/Root	${{\color{Goldenrod}{ }}}$ 0.3%, 2.91 KB
dist/views/CreateFirstUser	${{\color{Goldenrod}{ }}}$ 0.3%, 2.81 KB
dist/templates/Default	${{\color{Goldenrod}{ }}}$ 0.3%, 2.63 KB
dist/views/BrowseByFolder	${{\color{Goldenrod}{ }}}$ 0.3%, 2.61 KB
dist/views/CollectionFolders	${{\color{Goldenrod}{ }}}$ 0.3%, 2.44 KB
dist/views/ResetPassword	${{\color{Goldenrod}{ }}}$ 0.3%, 2.40 KB
dist/views/Logout	${{\color{Goldenrod}{ }}}$ 0.2%, 1.94 KB
(other)	${{\color{Goldenrod}{ ████▍ }}}$ 17.6%, 166.53 KB

Meta file: packages/payload/meta_index.json, Out file: esbuild/index.js

Path	Size
../../node_modules	${{\color{Goldenrod}{ ████████████████▉ }}}$ 67.8%, 887.23 KB
dist/fields/hooks	${{\color{Goldenrod}{ ▊ }}}$ 3.3%, 43.58 KB
dist/collections/operations	${{\color{Goldenrod}{ ▊ }}}$ 3.0%, 39.75 KB
dist/versions/migrations	${{\color{Goldenrod}{ ▎ }}}$ 1.4%, 18.50 KB
dist/auth/operations	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 15.74 KB
dist/globals/operations	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 13.17 KB
dist/fields/config	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 12.84 KB
dist/queues/operations	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 12.80 KB
dist/utilities/configToJSONSchema.js	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 12.07 KB
dist/fields/validations.js	${{\color{Goldenrod}{ ▏ }}}$ 0.8%, 10.54 KB
dist/bin/generateImportMap	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 8.77 KB
dist/collections/config	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 8.35 KB
dist/index.js	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 7.69 KB
dist/uploads/fetchAPI-multipart	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 7.67 KB
dist/database/migrations	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 7.54 KB
dist/config/orderable	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 6.83 KB
dist/collections/endpoints	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 6.22 KB
dist/config/sanitize.js	${{\color{Goldenrod}{ }}}$ 0.4%, 5.58 KB
dist/auth/strategies	${{\color{Goldenrod}{ }}}$ 0.4%, 5.50 KB
dist/auth/endpoints	${{\color{Goldenrod}{ }}}$ 0.4%, 5.42 KB
(other)	${{\color{Goldenrod}{ ████████ }}}$ 32.2%, 422.19 KB

Meta file: packages/payload/meta_shared.json, Out file: esbuild/exports/shared.js

Path	Size
../../node_modules	${{\color{Goldenrod}{ ███████████████████▎ }}}$ 77.1%, 127.13 KB
dist/fields/validations.js	${{\color{Goldenrod}{ █▌ }}}$ 6.4%, 10.54 KB
dist/config/orderable	${{\color{Goldenrod}{ ▍ }}}$ 1.9%, 3.13 KB
dist/fields/baseFields	${{\color{Goldenrod}{ ▍ }}}$ 1.7%, 2.79 KB
dist/utilities/deepCopyObject.js	${{\color{Goldenrod}{ ▍ }}}$ 1.5%, 2.54 KB
dist/auth/cookies.js	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 1.55 KB
dist/utilities/flattenTopLevelFields.js	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 1.42 KB
dist/fields/config	${{\color{Goldenrod}{ ▏ }}}$ 0.8%, 1.28 KB
dist/utilities/getVersionsConfig.js	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 1.04 KB
dist/utilities/flattenAllFields.js	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 943 B
dist/folders/utils	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 916 B
dist/utilities/unflatten.js	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 779 B
dist/utilities/sanitizeUserDataForEmail.js	${{\color{Goldenrod}{ }}}$ 0.4%, 713 B
dist/utilities/getFieldPermissions.js	${{\color{Goldenrod}{ }}}$ 0.4%, 651 B
dist/collections/config	${{\color{Goldenrod}{ }}}$ 0.3%, 570 B
dist/bin/generateImportMap	${{\color{Goldenrod}{ }}}$ 0.3%, 561 B
dist/auth/sessions.js	${{\color{Goldenrod}{ }}}$ 0.3%, 525 B
dist/fields/getFieldPaths.js	${{\color{Goldenrod}{ }}}$ 0.3%, 485 B
dist/utilities/getSafeRedirect.js	${{\color{Goldenrod}{ }}}$ 0.3%, 423 B
dist/utilities/deepMerge.js	${{\color{Goldenrod}{ }}}$ 0.3%, 413 B
(other)	${{\color{Goldenrod}{ █████▋ }}}$ 22.9%, 37.77 KB

Meta file: packages/richtext-lexical/meta_client.json, Out file: esbuild/exports/client_optimized/index.js

Path	Size
dist/features/blocks	${{\color{Goldenrod}{ ███▏ }}}$ 12.6%, 35.15 KB
dist/lexical/plugins	${{\color{Goldenrod}{ ██▉ }}}$ 11.5%, 32.00 KB
dist/lexical/ui	${{\color{Goldenrod}{ ██▏ }}}$ 8.7%, 24.36 KB
dist/features/experimental_table	${{\color{Goldenrod}{ ██▏ }}}$ 8.5%, 23.70 KB
dist/packages/@lexical	${{\color{Goldenrod}{ █▋ }}}$ 6.8%, 18.99 KB
dist/features/link	${{\color{Goldenrod}{ █▋ }}}$ 6.5%, 18.23 KB
dist/features/toolbars	${{\color{Goldenrod}{ █▌ }}}$ 6.4%, 17.75 KB
dist/features/upload	${{\color{Goldenrod}{ █▏ }}}$ 4.9%, 13.77 KB
dist/features/textState	${{\color{Goldenrod}{ █ }}}$ 4.0%, 11.08 KB
dist/features/relationship	${{\color{Goldenrod}{ ▊ }}}$ 3.2%, 9.03 KB
dist/lexical/utils	${{\color{Goldenrod}{ ▊ }}}$ 3.0%, 8.49 KB
dist/features/debug	${{\color{Goldenrod}{ ▋ }}}$ 2.7%, 7.39 KB
dist/utilities/fieldsDrawer	${{\color{Goldenrod}{ ▋ }}}$ 2.6%, 7.15 KB
dist/features/converters	${{\color{Goldenrod}{ ▋ }}}$ 2.5%, 7.05 KB
dist/lexical/config	${{\color{Goldenrod}{ ▍ }}}$ 1.8%, 5.08 KB
dist/features/lists	${{\color{Goldenrod}{ ▍ }}}$ 1.8%, 5.00 KB
dist/features/format	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 3.46 KB
dist/lexical/LexicalEditor.js	${{\color{Goldenrod}{ ▎ }}}$ 1.1%, 3.17 KB
dist/lexical/theme	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 2.62 KB
dist/features/indent	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 2.50 KB
(other)	${{\color{Goldenrod}{ █████████████████████▊ }}}$ 87.4%, 243.38 KB

Meta file: packages/ui/meta_client.json, Out file: esbuild/exports/client_optimized/index.js

Path	Size
../../node_modules	${{\color{Goldenrod}{ ████████████▍ }}}$ 49.7%, 578.99 KB
dist/elements/FolderView	${{\color{Goldenrod}{ ▋ }}}$ 2.5%, 29.29 KB
dist/elements/BulkUpload	${{\color{Goldenrod}{ ▌ }}}$ 2.4%, 27.61 KB
dist/elements/WhereBuilder	${{\color{Goldenrod}{ ▍ }}}$ 1.5%, 17.09 KB
dist/views/Edit	${{\color{Goldenrod}{ ▎ }}}$ 1.4%, 16.74 KB
dist/fields/Relationship	${{\color{Goldenrod}{ ▎ }}}$ 1.4%, 15.79 KB
dist/elements/Table	${{\color{Goldenrod}{ ▎ }}}$ 1.4%, 15.77 KB
dist/forms/Form	${{\color{Goldenrod}{ ▎ }}}$ 1.3%, 15.26 KB
dist/fields/Upload	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 14.20 KB
dist/fields/Blocks	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 13.70 KB
dist/elements/QueryPresets	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 10.32 KB
dist/elements/PublishButton	${{\color{Goldenrod}{ ▏ }}}$ 0.8%, 9.03 KB
dist/providers/Folders	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 8.45 KB
dist/elements/LivePreview	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 8.38 KB
dist/elements/ListHeader	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 7.90 KB
dist/elements/HTMLDiff	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 7.81 KB
dist/fields/Array	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 7.73 KB
dist/views/CollectionFolder	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 7.38 KB
dist/elements/ReactSelect	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 7.34 KB
dist/views/List	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 7.02 KB
(other)	${{\color{Goldenrod}{ ████████████▌ }}}$ 50.3%, 586.55 KB

Meta file: packages/ui/meta_shared.json, Out file: esbuild/exports/shared_optimized/index.js

Path	Size
dist/graphics/Logo	${{\color{Goldenrod}{ █████ }}}$ 20.0%, 3.12 KB
../../node_modules	${{\color{Goldenrod}{ ████▎ }}}$ 17.0%, 2.65 KB
dist/graphics/Icon	${{\color{Goldenrod}{ ██▍ }}}$ 9.8%, 1.52 KB
dist/utilities/formatDocTitle	${{\color{Goldenrod}{ ██▏ }}}$ 8.5%, 1.32 KB
dist/providers/TableColumns	${{\color{Goldenrod}{ █▍ }}}$ 5.5%, 862 B
dist/utilities/groupNavItems.js	${{\color{Goldenrod}{ █▎ }}}$ 5.2%, 814 B
dist/utilities/getGlobalData.js	${{\color{Goldenrod}{ █▏ }}}$ 4.9%, 762 B
dist/utilities/api.js	${{\color{Goldenrod}{ █▏ }}}$ 4.8%, 756 B
dist/elements/Translation	${{\color{Goldenrod}{ ▊ }}}$ 3.2%, 493 B
dist/utilities/handleTakeOver.js	${{\color{Goldenrod}{ ▋ }}}$ 2.8%, 440 B
dist/utilities/traverseForLocalizedFields.js	${{\color{Goldenrod}{ ▋ }}}$ 2.6%, 399 B
dist/elements/withMergedProps	${{\color{Goldenrod}{ ▌ }}}$ 2.2%, 339 B
dist/utilities/getVisibleEntities.js	${{\color{Goldenrod}{ ▌ }}}$ 2.1%, 329 B
dist/utilities/getNavGroups.js	${{\color{Goldenrod}{ ▍ }}}$ 1.9%, 301 B
dist/elements/WithServerSideProps	${{\color{Goldenrod}{ ▍ }}}$ 1.5%, 232 B
dist/utilities/handleGoBack.js	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 180 B
dist/fields/mergeFieldStyles.js	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 159 B
dist/utilities/handleBackToDashboard.js	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 152 B
dist/forms/Form	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 147 B
dist/utilities/abortAndIgnore.js	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 146 B
(other)	${{\color{Goldenrod}{ ████████████████████ }}}$ 80.0%, 12.51 KB

Details

Next to the size is how much the size has increased or decreased compared with the base branch of this PR.

• ‼️: Size increased by 20% or more. Special attention should be given to this.
• ⚠️: Size increased in acceptable range (lower than 20%).
• ✅: No change or even downsized.
• 🗑️: The out file is deleted: not found in base branch.
• 🆕: The out file is newly found: will be added to base branch.

[AlessioGr]

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