Implement plugin cache invalidation with ESLint-style metadata by nvrakesh06 · Pull Request #17808 · prettier/prettier

nvrakesh06 · 2025-08-23T11:02:10Z

Description

This PR implements plugin cache invalidation for Prettier to fix issue #17260. The implementation uses a simplified ESLint-style approach where plugins export a meta object with name and version information for proper cache invalidation.

Implementation

ESLint-Style Plugin Metadata

Plugins export a meta object with name, version, and optionally namespace properties
Follows the same pattern as ESLint plugins for consistency and familiarity
Enables automatic cache invalidation when plugin versions change
Fully backward compatible - plugins without metadata behave identically to before

Plugin Metadata Format

export const meta = {
  name: "prettier-plugin-example",
  version: "1.2.3",
  namespace: "example" // optional
};

Simplified Cache Implementation

Cache functions extract plugins from options.plugins internally
Preserves original plugin order for deterministic behavior
Clean API without redundant parameter passing

Files Modified

docs/cli.md - Updated CLI documentation with simplified cache approach
docs/plugins.md - Updated plugin documentation with ESLint-style metadata approach
src/main/plugins/plugin-signature.js - Simplified plugin signature logic
src/cli/format.js - Clean cache function calls
src/cli/format-results-cache.js - Extract plugins from options internally
tests/integration/__tests__/cache-plugin-invalidation.js - Integration tests
tests/unit/format-results-cache.test.js - Cache unit tests
tests/unit/plugin-signature.test.js - Plugin signature unit tests

Benefits

Automatic Cache Invalidation: Plugin version changes properly invalidate cache
Backward Compatibility: Existing plugins continue to work without modifications
ESLint-style Approach: Familiar metadata pattern for plugin developers
Simplified Implementation: Clean API without complex fallback mechanisms
Order Preservation: Plugin order is preserved for deterministic behavior
Comprehensive Testing: Full test coverage for all scenarios

Checklist

I've added tests to confirm my change works.
(If changing the API or CLI) I've documented the changes I've made (in the docs/ directory).
(If the change is user-facing) I've added my changes to changelog_unreleased/*/XXXX.md file following changelog_unreleased/TEMPLATE.md.
I've read the contributing guidelines.

Fixes: Cache invalidation on plugin upgrade with optional metadata #17260

Implements opt-in plugin metadata support for cache invalidation. Plugins can export prettierPluginMeta with name/version to enable proper cache invalidation when plugin versions change. Fully backward compatible - plugins without metadata behave identically. Fixes prettier#17260

Extends the plugin cache invalidation to include a package.json fallback when plugins don't export explicit prettierPluginMeta. This hybrid approach provides: 1. Explicit metadata (fastest, most reliable) 2. Package.json fallback (automatic for npm plugins) 3. Legacy behavior (unchanged for compatibility) Most existing npm-published plugins will now get automatic cache invalidation without any changes required. - Adds package.json reading with directory traversal - Includes caching to avoid repeated I/O - Comprehensive test coverage for all fallback scenarios - Updated documentation for hybrid approach

netlify · 2025-08-23T11:03:45Z

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- Add dependency injection to plugin-signature module for testability - Replace Jest mocking with manual mocks using dependency injection - Export packageJsonCache for test cleanup - Clear cache between tests to prevent test interference - All 15 unit tests now pass successfully

pkg-pr-new · 2025-08-23T13:00:55Z

Open in StackBlitz

yarn add https://pkg.pr.new/prettier/prettier/@prettier/[email protected]

yarn add https://pkg.pr.new/prettier/prettier/@prettier/[email protected]

yarn add https://pkg.pr.new/prettier/[email protected]

commit: 4aa3052

- Change plugin metadata from prettierPluginMeta to meta object (ESLint-style) - Remove package.json fallback system - plugins must implement .meta - Preserve original plugin order instead of sorting for deterministic behavior - Extract plugins from options internally instead of passing separately - Update all tests and documentation to reflect simplified approach - Remove complex fallback logic and caching mechanisms Addresses PR comments: 1. Use ESLint-style explanation for plugin metadata 2. Plugins should implement .meta instead of relying on package.json fallback 3. Order matters - don't sort plugins 4. Shouldn't plugins already exist in options? (fisker)

nvrakesh06 · 2025-08-24T13:09:27Z

@fisker Updated based on your comments. Please review when you get a chance.

nvrakesh06 · 2025-09-05T06:56:26Z

@fisker Just following up on this PR for review. Thanks

fisker · 2025-09-23T21:21:14Z

+
+  return {
+    ...supportInfoToContextOptions(supportInfo),
+    loadedPlugins,


This should not be done here, we can add a function to do the hash calculation and wrap with withPlugins(), then the function will receive loaded plugins.

Ah, you already have createPluginSignature, export the wrapped version in index.js should work.

fisker · 2025-09-23T21:27:46Z

+  // Create compact signature: "name@version,name@version"
+  return pluginMetadata
+    .map(({ name, version }) => `${name}@${version}`)
+    .join(",");


Can't we simply replace the whole function with

function createPluginSignature(plugins) { return plugins.map(plugin => `${plugin.meta?.name}@${plugin.meta?.version}`); }

?

fisker · 2025-09-23T21:34:09Z

+export const meta = {
+  name: "prettier-plugin-example",
+  version: "1.2.3",
+  namespace: "example"


The namespace should be removed, since we are not going to use. Eslint add this so user can use namespace/foo-rule to reference the rule.

fisker · 2025-09-23T21:39:19Z

+      "--plugin",
+      "./test-plugin.js",
+      "test.js",
+    ]);


I think we can print differnt result to simplify the tests.

Something like this

export default { meta: { name: "test-plugin", version: "1.0.0" }, languages: [ { name: "test-lang", parsers: ["test-parser"], extensions: [".js"] } ], parsers: { "test-parser": { parse: (text) => ({ /* whatever */ }), astFormat: "test-ast" } }, printers: { "test-ast": { print: (path) => '1.0.0' } } }

fisker · 2025-10-15T23:40:02Z

Hello, @nvrakesh06

I want make a change here, instead of plugin.meta.{name,version}, I'd like to move them to the root.
Doing this because, we already have a name field in the plugin when loading plugins (#18082 is improving it), we can take advantage of that, also simplify the plugin loading process.

nvrakesh06 added 2 commits August 23, 2025 16:20

nvrakesh06 mentioned this pull request Aug 23, 2025

Cache invalidation on plugin upgrade with optional metadata #17260

Open

nvrakesh06 marked this pull request as ready for review August 23, 2025 12:09