SettingsBuilder: allow maintenance scripts to manipulate config

Maintenance scripts often need to manipulate configuration settings.
This introduces a way to do this cleanly via SettingsBuilder,
removing the need to rely on global variables.

Bug: T294739
Bug: T294742
Bug: T300128
Change-Id: Ibf443fd564bbbf388cce8ab4dabba55ebca0dfa4

1 files changed, 86 insertions, 5 deletions

diff --git a/includes/Settings/SettingsBuilder.php b/includes/Settings/SettingsBuilder.php
index dfdd230312ba..a55eb6e9e4ae 100644
--- a/includes/Settings/SettingsBuilder.php
+++ b/includes/Settings/SettingsBuilder.php
@@ -37,6 +37,9 @@ class SettingsBuilder {
 	/** @var ConfigBuilder */
 	private $configSink;
 
+	/** @var Config */
+	private $config;
+
 	/** @var SettingsSource[] */
 	private $currentBatch;
 
@@ -47,6 +50,16 @@ class SettingsBuilder {
 	private $phpIniSink;
 
 	/**
+	 * Configuration that applies to SettingsBuilder itself.
+	 * Initialized by the constructor, may be overwritten by regular
+	 * config values. Merge strategies are currently not implemented
+	 * but can be added if needed.
+	 *
+	 * @var array
+	 */
+	private $settingsConfig;
+
+	/**
 	 * When we're done applying all settings.
 	 *
 	 * @var bool
@@ -76,6 +89,10 @@ class SettingsBuilder {
 		$this->configSink = $configSink;
 		$this->configSchema = new ConfigSchemaAggregator();
 		$this->phpIniSink = $phpIniSink;
+		$this->settingsConfig = [
+			'ExtensionDirectory' => "$baseDir/extensions",
+			'StyleDirectory' => "$baseDir/skins",
+		];
 		$this->reset();
 	}
 
@@ -153,7 +170,7 @@ class SettingsBuilder {
 	 * @return StatusValue
 	 */
 	public function validate(): StatusValue {
-		$config = $this->configSink->build();
+		$config = $this->getConfig();
 		$validator = new Validator();
 		$result = StatusValue::newGood();
 
@@ -183,9 +200,12 @@ class SettingsBuilder {
 	/**
 	 * Return a Config object with all the default settings loaded so far.
 	 *
+	 * @note This will implicitly call apply()
+	 *
 	 * @return Config
 	 */
 	public function getDefaultConfig(): Config {
+		$this->apply();
 		return new HashConfig( $this->configSchema->getDefaults() );
 	}
 
@@ -201,7 +221,12 @@ class SettingsBuilder {
 	 * @throws SettingsBuilderException
 	 */
 	public function apply(): self {
+		if ( !$this->currentBatch ) {
+			return $this;
+		}
+
 		$this->assertNotFinished();
+		$this->config = null;
 
 		$allSettings = $this->loadRecursive( $this->currentBatch );
 
@@ -267,6 +292,16 @@ class SettingsBuilder {
 	 * @param array $settings
 	 */
 	private function applySettings( array $settings ) {
+		// First extract config variables that change the behavior of SettingsBuilder.
+		// No merge strategies are applied, defaults are set in the constructor.
+		if ( isset( $settings['config'] ) ) {
+			foreach ( $this->settingsConfig as $key => $dummy ) {
+				if ( array_key_exists( $key, $settings['config'] ) ) {
+					$this->settingsConfig[$key] = $settings['config'][$key];
+				}
+			}
+		}
+
 		foreach ( $settings['config'] ?? [] as $key => $value ) {
 			$this->configSink->set(
 				$key,
@@ -298,10 +333,8 @@ class SettingsBuilder {
 		//       not just queued. We can't do this right now, because we need to preserve
 		//       interoperability with wfLoadExtension() being called from LocalSettings.php.
 
-		$config = $this->configSink->build();
-
 		if ( isset( $settings['extensions'] ) ) {
-			$extDir = $config->get( 'ExtensionDirectory' );
+			$extDir = $this->settingsConfig['ExtensionDirectory'];
 			foreach ( $settings['extensions'] ?? [] as $ext ) {
 				$path = "$extDir/$ext/extension.json"; // see wfLoadExtension
 				$this->extensionRegistry->queue( $path );
@@ -309,7 +342,7 @@ class SettingsBuilder {
 		}
 
 		if ( isset( $settings['skins'] ) ) {
-			$skinDir = $config->get( 'StyleDirectory' );
+			$skinDir = $this->settingsConfig['StyleDirectory'];
 			foreach ( $settings['skins'] ?? [] as $skin ) {
 				$path = "$skinDir/$skin/skin.json"; // see wfLoadSkin
 				$this->extensionRegistry->queue( $path );
@@ -317,6 +350,54 @@ class SettingsBuilder {
 		}
 	}
 
+	/**
+	 * Sets the value of a config variable.
+	 * This is a shorthand for loadArray().
+	 * @unstable
+	 *
+	 * @param string $key the name of the config setting
+	 * @param mixed $value The value to set
+	 *
+	 * @return $this
+	 */
+	public function setConfigValue( string $key, $value ): self {
+		$this->loadArray( [ 'config' => [ $key => $value ] ] );
+		return $this;
+	}
+
+	/**
+	 * Sets the value of multiple config variables.
+	 * This is a shorthand for loadArray().
+	 * @unstable
+	 *
+	 * @param array $values An associative array mapping names to values.
+	 *
+	 * @return $this
+	 */
+	public function setConfigValues( array $values ): self {
+		$this->loadArray( [ 'config' => $values ] );
+		return $this;
+	}
+
+	/**
+	 * Returns the config loaded so far. Implicitly triggers apply() when needed.
+	 *
+	 * @note This will implicitly call apply()
+	 *
+	 * @unstable
+	 * @return Config
+	 */
+	public function getConfig(): Config {
+		if ( $this->config && !$this->currentBatch ) {
+			return $this->config;
+		}
+
+		$this->apply();
+		$this->config = $this->configSink->build();
+
+		return $this->config;
+	}
+
 	private function reset() {
 		$this->currentBatch = [];
 	}