Make transcluded special pages not disable cache in miser mode.

Previously {{Special:Foo}} would cause parser cache to be disabled,
now have a method in SpecialPage to control this behaviour and set
arbitrary caching times.

Note: This does not affect caching of direct views to the special page

The new default is now disabling cache if not in miser mode,
otherwise setting to 1 hour, except for Special:Recentchanges
and Special:Newpages which set to 5 minutes. These values are
possibly really low, but for now I think best to be close to the
old behaviour. We had 0 caching for these things for years, and
afaik it hasn't caused any big issues. Part of me wonders if
Special:Recentchanges should stay at 0, but that sounds crazy.

This change also causes transcluded special pages to not be
"per-user" if they are being cached (Specificly $wgUser et al
become 127.0.0.1).

Bug: 60561
Change-Id: Id9ce987adeaa69d886eb1c5cd74c01072583e84d

includes/parser/Parser.php

@@ -3125,6 +3125,7 @@ class Parser {
 					&& $this->mOptions->getAllowSpecialInclusion()
 					&& $this->ot['html']
 				) {
+					$specialPage = SpecialPageFactory::getPage( $title->getDBkey() );
 					// Pass the template arguments as URL parameters.
 					// "uselang" will have no effect since the Language object
 					// is forced to the one defined in ParserOptions.
@@ -3143,7 +3144,12 @@ class Parser {
 					$context = new RequestContext;
 					$context->setTitle( $title );
 					$context->setRequest( new FauxRequest( $pageArgs ) );
-					$context->setUser( $this->getUser() );
+					if ( $specialPage && $specialPage->maxIncludeCacheTime() === 0 ) {
+						$context->setUser( $this->getUser() );
+					} else {
+						// If this page is cached, then we better not be per user.
+						$context->setUser( User::newFromName( '127.0.0.1', false ) );
+					}
 					$context->setLanguage( $this->mOptions->getUserLangObj() );
 					$ret = SpecialPageFactory::capturePath( $title, $context );
 					if ( $ret ) {
@@ -3151,8 +3157,9 @@ class Parser {
 						$this->mOutput->addOutputPageMetadata( $context->getOutput() );
 						$found = true;
 						$isHTML = true;
-						// Severely reduce cache time to keep content dynamic
-						$this->mOutput->updateCacheExpiry( 30 );
+						if ( $specialPage && $specialPage->maxIncludeCacheTime() !== false ) {
+							$this->mOutput->updateCacheExpiry( $specialPage->maxIncludeCacheTime() );
+						}
 					}
 				} elseif ( MWNamespace::isNonincludable( $title->getNamespace() ) ) {
 					$found = false; # access denied

includes/specialpage/SpecialPage.php

@@ -175,6 +175,25 @@ class SpecialPage {
 		return $this->mIncludable;
 	}
 
+	/**
+	 * How long to cache page when it is being included.
+	 *
+	 * @note If cache time is not 0, then the current user becomes an anon
+	 *   if you want to do any per-user customizations, than this method
+	 *   must be overriden to return 0.
+	 * @since 1.26
+	 * @return int Time in seconds, 0 to disable caching altogether,
+	 *  false to use the parent page's cache settings
+	 */
+	public function maxIncludeCacheTime() {
+		global $wgMiserMode;
+		if ( !$wgMiserMode ) {
+			return 0;
+		} else {
+			return 60*60;
+		}
+	}
+
 	/**
 	 * Whether the special page is being evaluated via transclusion
 	 * @param bool $x

includes/specials/SpecialNewpages.php

@@ -478,4 +478,18 @@ class SpecialNewpages extends IncludableSpecialPage {
 	protected function getGroupName() {
 		return 'changes';
 	}
+
+	/**
+	 * How long to cache page when it is being included.
+	 *
+	 * @return int Time in seconds, 0 to disable caching altogether
+	 */
+	public function maxIncludeCacheTime() {
+		global $wgMiserMode;
+		if ( !$wgMiserMode ) {
+			return 0;
+		} else {
+			return 60*5;
+		}
+	}
 }

includes/specials/SpecialRecentchanges.php

@@ -794,4 +794,19 @@ class SpecialRecentChanges extends ChangesListSpecialPage {
 	public function isIncludable() {
 		return true;
 	}
+
+	/**
+	 * How long to cache page when it is being included.
+	 *
+	 * @return int|bool Time in seconds, 0 to disable caching altogether
+	 */
+	public function maxIncludeCacheTime() {
+		global $wgMiserMode;
+		if ( !$wgMiserMode ) {
+			return 0;
+		} else {
+			return 60*5;
+		}
+	}
+
 }