feat(lexicon): validate value on set

lib/private/AppConfig.php

@@ -795,11 +795,19 @@ private function setTypedValue(
 		int $type,
 	): bool {
 		$this->assertParams($app, $key);
-		if (!$this->matchAndApplyLexiconDefinition($app, $key, $lazy, $type)) {
+		/** @var ?Entry $lexiconEntry */
+		$lexiconEntry = null;
+		if (!$this->matchAndApplyLexiconDefinition($app, $key, $lazy, $type, lexiconEntry: $lexiconEntry)) {
 			return false; // returns false as database is not updated
 		}
 		$this->loadConfig(null, $lazy ?? true);
 
+		// lexicon entry might have requested a check on the value
+		$confirmationClosure = $lexiconEntry?->onSetConfirmation();
+		if ($confirmationClosure !== null && !$confirmationClosure($value)) {
+			return false;
+		}
+
 		$sensitive = $this->isTyped(self::VALUE_SENSITIVE, $type);
 		$inserted = $refreshCache = false;
 

lib/private/Config/UserConfig.php

@@ -1100,12 +1100,20 @@ private function setTypedValue(
 		}
 
 		$this->assertParams($userId, $app, $key);
-		if (!$this->matchAndApplyLexiconDefinition($userId, $app, $key, $lazy, $type, $flags)) {
+		/** @var ?Entry $lexiconEntry */
+		$lexiconEntry = null;
+		if (!$this->matchAndApplyLexiconDefinition($userId, $app, $key, $lazy, $type, $flags, lexiconEntry: $lexiconEntry)) {
 			// returns false as database is not updated
 			return false;
 		}
 		$this->loadConfig($userId, $lazy);
 
+		// lexicon entry might have requested a check on the value
+		$confirmationClosure = $lexiconEntry?->onSetConfirmation();
+		if ($confirmationClosure !== null && !$confirmationClosure($value)) {
+			return false;
+		}
+
 		$inserted = $refreshCache = false;
 		$origValue = $value;
 		$sensitive = $this->isFlagged(self::FLAG_SENSITIVE, $flags);
@@ -1937,6 +1945,7 @@ private function matchAndApplyLexiconDefinition(
 		ValueType &$type = ValueType::MIXED,
 		int &$flags = 0,
 		?string &$default = null,
+		?Entry &$lexiconEntry = null,
 	): bool {
 		$configDetails = $this->getConfigDetailsFromLexicon($app);
 		if (array_key_exists($key, $configDetails['aliases']) && !$this->ignoreLexiconAliases) {
@@ -1953,18 +1962,18 @@ private function matchAndApplyLexiconDefinition(
 			return true;
 		}
 
-		/** @var Entry $configValue */
-		$configValue = $configDetails['entries'][$key];
+		/** @var Entry $lexiconEntry */
+		$lexiconEntry = $configDetails['entries'][$key];
 		if ($type === ValueType::MIXED) {
 			// we overwrite if value was requested as mixed
-			$type = $configValue->getValueType();
-		} elseif ($configValue->getValueType() !== $type) {
+			$type = $lexiconEntry->getValueType();
+		} elseif ($lexiconEntry->getValueType() !== $type) {
 			throw new TypeConflictException('The user config key ' . $app . '/' . $key . ' is typed incorrectly in relation to the config lexicon');
 		}
 
-		$lazy = $configValue->isLazy();
-		$flags = $configValue->getFlags();
-		if ($configValue->isDeprecated()) {
+		$lazy = $lexiconEntry->isLazy();
+		$flags = $lexiconEntry->getFlags();
+		if ($lexiconEntry->isDeprecated()) {
 			$this->logger->notice('User config key ' . $app . '/' . $key . ' is set as deprecated.');
 		}
 
@@ -1976,7 +1985,7 @@ private function matchAndApplyLexiconDefinition(
 
 		// only look for default if needed, default from Lexicon got priority if not overwritten by admin
 		if ($default !== null) {
-			$default = $this->getSystemDefault($app, $configValue) ?? $configValue->getDefault($this->presetManager->getLexiconPreset()) ?? $default;
+			$default = $this->getSystemDefault($app, $lexiconEntry) ?? $lexiconEntry->getDefault($this->presetManager->getLexiconPreset()) ?? $default;
 		}
 
 		// returning false will make get() returning $default and set() not changing value in database

lib/public/Config/Lexicon/Entry.php

@@ -35,8 +35,10 @@ class Entry {
 	 * @param string|null $rename source in case of a rename of a config key.
 	 * @param int $options additional bitflag options {@see self::RENAME_INVERT_BOOLEAN}
 	 * @param string $note additional note and warning related to the use of the config key.
+	 * @param (Closure(string $value): bool)|null $onSetConfirm callback to be called when a config value is set. {@see onSetConfirmation()} for more details.
 	 *
 	 * @since 32.0.0
+	 * @since 34.0.0 added $onSetConfirm
 	 * @psalm-suppress PossiblyInvalidCast
 	 * @psalm-suppress RiskyCast
 	 */
@@ -51,6 +53,7 @@ public function __construct(
 		private readonly ?string $rename = null,
 		private readonly int $options = 0,
 		private readonly string $note = '',
+		private readonly ?Closure $onSetConfirm = null,
 	) {
 		// key can only contain alphanumeric chars and underscore "_"
 		if (preg_match('/[^[:alnum:]_]/', $key)) {
@@ -195,6 +198,20 @@ public function getNote(): string {
 		return $this->note;
 	}
 
+	/**
+	 * Returns an optional callback to be called when a config value is set.
+	 * If not null, the callback will be called before the config value is set.
+	 * Callable must accept a string-typed parameter containing the new value.
+	 * String-typed parameter can be referenced and modified to a new value from the Callable.
+	 * Callback must return a boolean indicating if the set operation should be allowed.
+	 *
+	 * @return (Closure(string $value): bool)|null
+	 * @since 34.0.0
+	 */
+	public function onSetConfirmation(): ?Closure {
+		return $this->onSetConfirm;
+	}
+
 	/**
 	 * returns if config key is set as lazy
 	 *