Properly configure the php.ini for PCOV.

This ensures that `pcov.initial.files` is set to `10000` and `pcov.directory` is configured dynamically based on the value of `LOCAL_DIR`.

Author: desrosj

tools/local-env/php-config.ini

@@ -5,3 +5,9 @@ post_max_size = 1G
 xdebug.start_with_request=trigger
 xdebug.discover_client_host=true
 xdebug.client_host=host.docker.internal
+
+# Pre-sizes the internal file tracking array for the thousands of files under
+# `src/` or `build/`, avoiding reallocation churn during test warmup.
+#
+# The default of 64 is far too low here.
+pcov.initial.files=10000

tools/local-env/scripts/docker.js

@@ -20,6 +20,25 @@ if ( [ 'exec', 'run' ].includes( dockerCommand[0] ) && ! process.stdin.isTTY ) {
 	dockerCommand.splice( 1, 0, '--no-TTY' );
 }
 
+/*
+ * `pcov.directory` restricts instrumentation to `src/`, so PCOV does not record hits for `vendor/`, `tests/`, or
+ * WordPress test fixtures that PHPUnit would discard at report time anyway.
+ */
+if ( process.env.LOCAL_PHP_PCOV === 'true' && dockerCommand.includes( '--coverage-clover' ) ) {
+	const phpunitIdx = dockerCommand.findIndex( ( arg ) => typeof arg === 'string' && arg.endsWith( 'phpunit' ) );
+	if ( phpunitIdx !== -1 ) {
+		const localDir = process.env.LOCAL_DIR || 'src';
+		dockerCommand.splice(
+			phpunitIdx,
+			1,
+			'php',
+			'-d',
+			`pcov.directory=/var/www/${ localDir }`,
+			dockerCommand[ phpunitIdx ]
+		);
+	}
+}
+
 // Add a --defaults flag to any db command WP-CLI command. See https://core.trac.wordpress.org/ticket/63876.
 if ( dockerCommand.includes( 'cli' ) && dockerCommand.includes( 'db' ) && ! dockerCommand.includes( '--defaults' ) ) {
 	dockerCommand.push( '--defaults' );