Add temporary feature flag for logout confirmation

Add a temporary feature flag that is going to be covering the work
around implementing a logout confirmation.

Bug: T357484
Change-Id: I3ee8f52976cb956e24f32115c02903c5c4f358c3

docs/config-schema.yaml

@@ -7997,3 +7997,9 @@ config-schema:
         description: |-
             Whether to use Codex in Special:Block form.
             This is a temporary feature flag.
+    ShowLogoutConfirmation:
+        default: false
+        type: boolean
+        description: |-
+            Whether to display a confirmation screen during user log out.
+            This is a temporary feature flag.

docs/config-vars.php

@@ -4434,3 +4434,9 @@ $wgEditRecoveryExpiry = null;
  * @see MediaWiki\MainConfigSchema::UseCodexSpecialBlock
  */
 $wgUseCodexSpecialBlock = null;
+
+/**
+ * Config variable stub for the ShowLogoutConfirmation setting, for use by phpdoc and IDEs.
+ * @see MediaWiki\MainConfigSchema::ShowLogoutConfirmation
+ */
+$wgShowLogoutConfirmation = null;

includes/MainConfigNames.php

@@ -4450,4 +4450,10 @@ class MainConfigNames {
 	 */
 	public const UseCodexSpecialBlock = 'UseCodexSpecialBlock';
 
+	/**
+	 * Name constant for the ShowLogoutConfirmation setting, for use with Config::get()
+	 * @see MainConfigSchema::ShowLogoutConfirmation
+	 */
+	public const ShowLogoutConfirmation = 'ShowLogoutConfirmation';
+
 }

includes/MainConfigSchema.php

@@ -12795,6 +12795,14 @@ class MainConfigSchema {
 		'type' => 'boolean',
 	];
 
+	/**
+	 * Whether to display a confirmation screen during user log out.
+	 * This is a temporary feature flag.
+	 */
+	public const ShowLogoutConfirmation = [
+		'default' => false,
+		'type' => 'boolean',
+	];
 	// endregion -- End Miscellaneous
 
 }

includes/config-schema.php

@@ -2512,6 +2512,7 @@ return [
 			'EnableEditRecovery' => false,
 			'EditRecoveryExpiry' => 2592000,
 			'UseCodexSpecialBlock' => false,
+			'ShowLogoutConfirmation' => false,
 		],
 		'type' => [
 			'ConfigRegistry' => 'object',
@@ -2988,6 +2989,7 @@ return [
 			'EnableEditRecovery' => 'boolean',
 			'EditRecoveryExpiry' => 'integer',
 			'UseCodexSpecialBlock' => 'boolean',
+			'ShowLogoutConfirmation' => 'boolean',
 		],
 		'mergeStrategy' => [
 			'TiffThumbnailType' => 'replace',