Automatically assign plugin-specific milestones

.github/workflows/add-pr-labels.yml

@@ -18,8 +18,18 @@ jobs:
       contents: read
       pull-requests: write
     steps:
+      - name: Check out the repository
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+
       - name: Apply plugin labels from changed paths
         uses: actions/labeler@b8dd2d9be0f68b860e7dae5dae7d772984eacd6d # v6.2.0
         with:
           configuration-path: .github/labeler-config.yml
           sync-labels: true
+
+      - name: Assign the primary plugin milestone
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
+        with:
+          script: |
+            const { assignPluginMilestone } = require('./bin/plugin/lib/assign-plugin-milestone');
+            await assignPluginMilestone({ github, context, core });

.github/workflows/js-lint.yml

@@ -60,6 +60,8 @@ jobs:
         run: npm ci
       - name: JS Lint
         run: npm run lint-js
+      - name: JS Unit Tests
+        run: npm run test-unit-js
       - name: JSON Schema Validation
         run: npm run lint-json
       - name: TypeScript compile

bin/plugin/lib/assign-plugin-milestone.js

@@ -0,0 +1,240 @@
+/**
+ * Pull request milestone assignment helpers.
+ *
+ * @since n.e.x.t
+ */
+
+/**
+ * Internal dependencies
+ */
+const { plugins } = require( '../../../plugins.json' );
+
+/** @typedef {import('@octokit/rest').Octokit} GitHub */
+
+/**
+ * @typedef PullRequestFileStats
+ *
+ * @property {string}  filename          File path after the change.
+ * @property {number}  additions         Number of added lines.
+ * @property {number}  deletions         Number of deleted lines.
+ * @property {string=} previous_filename File path before a rename.
+ */
+
+/**
+ * @typedef MilestoneReference
+ *
+ * @property {number} number Milestone number.
+ * @property {string} title  Milestone title.
+ */
+
+/**
+ * @typedef WorkflowContext
+ *
+ * @property {{ owner: string, repo: string }}                                            repo    Repository details.
+ * @property {{ pull_request?: { number: number, milestone?: MilestoneReference|null } }} payload Event payload.
+ */
+
+/**
+ * @typedef WorkflowLogger
+ *
+ * @property {(message: string) => void} info    Logs an informational message.
+ * @property {(message: string) => void} warning Logs a warning message.
+ */
+
+/**
+ * Returns the plugin slug for a repository path.
+ *
+ * @since n.e.x.t
+ *
+ * @param {string}   filePath    Repository-relative file path.
+ * @param {string[]} pluginSlugs Known plugin slugs.
+ * @return {string|null} Plugin slug, or null when the path is not for a plugin.
+ */
+function getPluginSlugForPath( filePath, pluginSlugs = plugins ) {
+	const matches = filePath.match( /^plugins\/([^/]+)\// );
+	if ( ! matches || ! pluginSlugs.includes( matches[ 1 ] ) ) {
+		return null;
+	}
+
+	return matches[ 1 ];
+}
+
+/**
+ * Counts changed lines for each plugin represented in a pull request.
+ *
+ * For cross-plugin renames, additions belong to the destination plugin and
+ * deletions belong to the source plugin.
+ *
+ * @since n.e.x.t
+ *
+ * @param {PullRequestFileStats[]} files       Pull request files.
+ * @param {string[]}               pluginSlugs Known plugin slugs.
+ * @return {Record<string, number>} Changed line totals keyed by plugin slug.
+ */
+function countPluginLineChanges( files, pluginSlugs = plugins ) {
+	/** @type {Record<string, number>} */
+	const lineChanges = {};
+
+	for ( const file of files ) {
+		const pluginSlug = getPluginSlugForPath( file.filename, pluginSlugs );
+		const previousPluginSlug = file.previous_filename
+			? getPluginSlugForPath( file.previous_filename, pluginSlugs )
+			: null;
+
+		if ( file.previous_filename && pluginSlug !== previousPluginSlug ) {
+			if ( pluginSlug ) {
+				lineChanges[ pluginSlug ] =
+					( lineChanges[ pluginSlug ] || 0 ) + file.additions;
+			}
+			if ( previousPluginSlug ) {
+				lineChanges[ previousPluginSlug ] =
+					( lineChanges[ previousPluginSlug ] || 0 ) + file.deletions;
+			}
+			continue;
+		}
+
+		if ( pluginSlug ) {
+			lineChanges[ pluginSlug ] =
+				( lineChanges[ pluginSlug ] || 0 ) +
+				file.additions +
+				file.deletions;
+		}
+	}
+
+	return lineChanges;
+}
+
+/**
+ * Returns the plugin with the unique highest changed-line total.
+ *
+ * @since n.e.x.t
+ *
+ * @param {Record<string, number>} lineChanges Changed lines keyed by plugin slug.
+ * @return {string|null} Primary plugin slug, or null for no changes or a tie.
+ */
+function getPrimaryPluginSlug( lineChanges ) {
+	const rankedPlugins = Object.entries( lineChanges )
+		.filter( ( [ , changedLines ] ) => changedLines > 0 )
+		.sort(
+			( [ firstSlug, firstLines ], [ secondSlug, secondLines ] ) =>
+				secondLines - firstLines ||
+				firstSlug.localeCompare( secondSlug )
+		);
+
+	if (
+		! rankedPlugins.length ||
+		( rankedPlugins[ 1 ] &&
+			rankedPlugins[ 0 ][ 1 ] === rankedPlugins[ 1 ][ 1 ] )
+	) {
+		return null;
+	}
+
+	return rankedPlugins[ 0 ][ 0 ];
+}
+
+/**
+ * Selects the most appropriate open milestone for a plugin.
+ *
+ * The generic "n.e.x.t" milestone is preferred. A versioned milestone is
+ * selected only when it is the sole open candidate for the plugin.
+ *
+ * @since n.e.x.t
+ *
+ * @param {MilestoneReference[]} milestones Open repository milestones.
+ * @param {string}               pluginSlug Plugin slug.
+ * @return {MilestoneReference|null} Selected milestone, or null when ambiguous.
+ */
+function selectPluginMilestone( milestones, pluginSlug ) {
+	const pluginMilestones = milestones.filter( ( milestone ) =>
+		milestone.title.startsWith( `${ pluginSlug } ` )
+	);
+	const nextMilestone = pluginMilestones.find(
+		( milestone ) => milestone.title === `${ pluginSlug } n.e.x.t`
+	);
+
+	if ( nextMilestone ) {
+		return nextMilestone;
+	}
+
+	return pluginMilestones.length === 1 ? pluginMilestones[ 0 ] : null;
+}
+
+/**
+ * Assigns a pull request to the milestone for its primary plugin.
+ *
+ * @since n.e.x.t
+ *
+ * @param {Object}          options         Assignment options.
+ * @param {GitHub}          options.github  Authenticated GitHub client.
+ * @param {WorkflowContext} options.context Workflow event context.
+ * @param {WorkflowLogger}  options.core    Workflow logger.
+ * @return {Promise<void>} Promise resolving when assignment is complete.
+ */
+async function assignPluginMilestone( { github, context, core } ) {
+	const pullRequest = context.payload.pull_request;
+	if ( ! pullRequest ) {
+		throw new Error(
+			'The workflow event does not contain a pull request.'
+		);
+	}
+
+	const files = await github.paginate( github.rest.pulls.listFiles, {
+		...context.repo,
+		pull_number: pullRequest.number,
+		per_page: 100,
+	} );
+	const lineChanges = countPluginLineChanges( files );
+	const pluginSlug = getPrimaryPluginSlug( lineChanges );
+
+	if ( ! pluginSlug ) {
+		core.info(
+			`No unique primary plugin found. Changed lines by plugin: ${ JSON.stringify(
+				lineChanges
+			) }`
+		);
+		return;
+	}
+
+	if ( pullRequest.milestone?.title.startsWith( `${ pluginSlug } ` ) ) {
+		core.info(
+			`Pull request is already assigned to ${ pullRequest.milestone.title }.`
+		);
+		return;
+	}
+
+	const milestones = await github.paginate(
+		github.rest.issues.listMilestones,
+		{
+			...context.repo,
+			state: 'open',
+			per_page: 100,
+		}
+	);
+	const milestone = selectPluginMilestone( milestones, pluginSlug );
+
+	if ( ! milestone ) {
+		core.warning(
+			`No unambiguous open milestone found for ${ pluginSlug }; leaving the milestone unchanged.`
+		);
+		return;
+	}
+
+	await github.rest.issues.update( {
+		...context.repo,
+		issue_number: pullRequest.number,
+		milestone: milestone.number,
+	} );
+	core.info(
+		`Assigned ${
+			milestone.title
+		} based on changed lines: ${ JSON.stringify( lineChanges ) }`
+	);
+}
+
+module.exports = {
+	assignPluginMilestone,
+	countPluginLineChanges,
+	getPluginSlugForPath,
+	getPrimaryPluginSlug,
+	selectPluginMilestone,
+};

bin/plugin/lib/assign-plugin-milestone.test.js

@@ -0,0 +1,113 @@
+/**
+ * Tests for pull request milestone assignment helpers.
+ *
+ * @since n.e.x.t
+ */
+
+const assert = require( 'node:assert/strict' );
+const { test } = require( 'node:test' );
+
+const {
+	countPluginLineChanges,
+	getPluginSlugForPath,
+	getPrimaryPluginSlug,
+	selectPluginMilestone,
+} = require( './assign-plugin-milestone' );
+
+test( 'gets a known plugin slug from a repository path', () => {
+	assert.equal(
+		getPluginSlugForPath( 'plugins/auto-sizes/hooks.php' ),
+		'auto-sizes'
+	);
+	assert.equal( getPluginSlugForPath( 'plugins/unknown/hooks.php' ), null );
+	assert.equal( getPluginSlugForPath( 'README.md' ), null );
+} );
+
+test( 'counts additions and deletions by plugin', () => {
+	assert.deepEqual(
+		countPluginLineChanges( [
+			{
+				filename: 'plugins/auto-sizes/hooks.php',
+				additions: 4,
+				deletions: 2,
+			},
+			{
+				filename: 'plugins/auto-sizes/readme.txt',
+				additions: 1,
+				deletions: 1,
+			},
+			{
+				filename: 'plugins/embed-optimizer/load.php',
+				additions: 3,
+				deletions: 0,
+			},
+			{ filename: 'README.md', additions: 100, deletions: 100 },
+		] ),
+		{
+			'auto-sizes': 8,
+			'embed-optimizer': 3,
+		}
+	);
+} );
+
+test( 'splits a cross-plugin rename between its source and destination', () => {
+	assert.deepEqual(
+		countPluginLineChanges( [
+			{
+				filename: 'plugins/embed-optimizer/moved.php',
+				previous_filename: 'plugins/auto-sizes/moved.php',
+				additions: 5,
+				deletions: 7,
+			},
+		] ),
+		{
+			'auto-sizes': 7,
+			'embed-optimizer': 5,
+		}
+	);
+} );
+
+test( 'selects only a unique primary plugin', () => {
+	assert.equal(
+		getPrimaryPluginSlug( { 'auto-sizes': 8, 'embed-optimizer': 3 } ),
+		'auto-sizes'
+	);
+	assert.equal(
+		getPrimaryPluginSlug( { 'auto-sizes': 8, 'embed-optimizer': 8 } ),
+		null
+	);
+	assert.equal( getPrimaryPluginSlug( {} ), null );
+} );
+
+test( 'prefers the generic next milestone for a plugin', () => {
+	assert.deepEqual(
+		selectPluginMilestone(
+			[
+				{ number: 1, title: 'auto-sizes 3.0.0' },
+				{ number: 2, title: 'auto-sizes n.e.x.t' },
+			],
+			'auto-sizes'
+		),
+		{ number: 2, title: 'auto-sizes n.e.x.t' }
+	);
+} );
+
+test( 'selects a sole versioned milestone and rejects ambiguous versions', () => {
+	assert.deepEqual(
+		selectPluginMilestone(
+			[ { number: 1, title: 'optimization-detective 1.1.0' } ],
+			'optimization-detective'
+		),
+		{ number: 1, title: 'optimization-detective 1.1.0' }
+	);
+	assert.equal(
+		selectPluginMilestone(
+			[
+				{ number: 1, title: 'optimization-detective 1.0.0-beta6' },
+				{ number: 2, title: 'optimization-detective 1.1.0' },
+			],
+			'optimization-detective'
+		),
+		null
+	);
+} );

package.json

@@ -69,6 +69,7 @@
 		"test-e2e": "wp-scripts test-playwright --config tools/e2e/playwright.config.ts",
 		"test-e2e:debug": "wp-scripts test-playwright --config tools/e2e/playwright.config.ts --ui",
 		"test-e2e:auto-sizes": "wp-scripts test-playwright --config tools/e2e/playwright.config.ts --project=auto-sizes",
+		"test-unit-js": "node --test",
 		"lint-php": "composer lint:all",
 		"test-php": "wp-env --config=.wp-env.test.json run wordpress --env-cwd=/var/www/html/wp-content/plugins/performance composer test:plugins",
 		"test-php-watch": "./bin/test-php-watch.sh",