Respond to some messages from Phan on PHP 8.1

* ForkController, OrderedStreamingForkController: indeed pcntl_fork()
  can't return false.
* RL\Image: Specify type instead of using suppression, since the issue
  name changes.
* VueComponentParser: Accept complaint about nullable nodeValue.
* Disable PHP 8.0 polyfill stubs when running on PHP 8.0+ to avoid
  duplicate interface errors.
* Add Socket stub and use it in LegacyHandler instead of multiple
  existing suppressions.
* MemcachedPeclBagOStuff: accept complaint recommending !$result over
  $result === false when the type is boolean.
* MemcachedPeclBagOStuff: fix probable bug, ignoring errors from
  Memcached::getMulti(). Phan noticed that $res=false was unreachable,
  but it should probably be reachable.
* DatabaseMysqli: accept complaint that $this->conn->errno is already
  known to be an int. It was probably a hack for some previous version
  of Phan.
* BcryptPassword, MWOldPassword, MWSaltedPassword: accept complaint that
  the !is_string() checks are unnecessary, after code review of PHP.
* Pbkdf2PasswordUsingHashExtension: note that contrary to Phan's
  suggestion, this check is necessary.
* DefaultPreferencesFactory: remove an existing hack for
  array_diff_key(), no longer necessary on 7.4 and causes an error on
  8.1. Use coalesce instead of cast for the remaining
  array_intersect_key() hack since it better shows that we are casting
  away null.
* FullSearchResultWidget: fix likely bug involving strict comparison
  between a float and an int.
* SpecialWatchlist: accept complaint that $selectedHours is
  unconditionally a float, being the return value of round(), and thus
  the cast is unnecessary.
* Add stub for AllowDynamicProperties, resolving an error in User.php.
* Xml: accept complaint that $encMonth is already known to be an int.

Six errors remain. These need suppressions or otherwise conflict with
PHP 7.4 support.

Bug: T322278
Change-Id: Ie375bbc8ccf22330b9a169e8da98f2bbe26ec8b9

.phan/config.php

@@ -30,6 +30,8 @@ $cfg['file_list'] = array_merge(
 	class_exists( PEAR::class ) ? [] : [ '.phan/stubs/mail.php' ],
 	defined( 'PASSWORD_ARGON2ID' ) ? [] : [ '.phan/stubs/password.php' ],
 	class_exists( ValueError::class ) ? [] : [ '.phan/stubs/ValueError.php' ],
+	class_exists( Socket::class ) ? [] : [ '.phan/stubs/Socket.php' ],
+	class_exists( AllowDynamicProperties::class ) ? [] : [ '.phan/stubs/AllowDynamicProperties.php' ],
 	[
 		// This makes constants and globals known to Phan before processing all other files.
 		// You can check the parser order with --dump-parsed-file-list
@@ -51,6 +53,20 @@ $cfg['exclude_file_list'] = array_merge(
 	]
 );
 
+if ( PHP_VERSION_ID >= 80000 ) {
+	// Exclude PHP 8.0 polyfills if PHP 8.0+ is running
+	$cfg['exclude_file_list'] = array_merge(
+		$cfg['exclude_file_list'],
+		[
+			'vendor/symfony/polyfill-php80/Resources/stubs/Attribute.php',
+			'vendor/symfony/polyfill-php80/Resources/stubs/PhpToken.php',
+			'vendor/symfony/polyfill-php80/Resources/stubs/Stringable.php',
+			'vendor/symfony/polyfill-php80/Resources/stubs/UnhandledMatchError.php',
+			'vendor/symfony/polyfill-php80/Resources/stubs/ValueError.php',
+		]
+	);
+}
+
 $cfg['analyzed_file_extensions'] = array_merge(
 	$cfg['analyzed_file_extensions'] ?? [ 'php' ],
 	[ 'inc' ]

.phan/stubs/AllowDynamicProperties.php

@@ -0,0 +1,6 @@
+<?php
+
+// Stub for PHP 8.2's AllowDynamicProperties class
+#[Attribute]
+class AllowDynamicProperties {
+}

.phan/stubs/Socket.php

@@ -0,0 +1,5 @@
+<?php
+
+// Stub for PHP 8.1's Socket class
+final class Socket {
+}

includes/Maintenance/ForkController.php

@@ -189,7 +189,7 @@ class ForkController {
 		for ( $i = 0; $i < $numProcs; $i++ ) {
 			// Do the fork
 			$pid = pcntl_fork();
-			if ( $pid === -1 || $pid === false ) {
+			if ( $pid === -1 ) {
 				echo "Error creating child processes\n";
 				exit( 1 );
 			}

includes/Maintenance/OrderedStreamingForkController.php

@@ -94,7 +94,7 @@ class OrderedStreamingForkController extends ForkController {
 			$sockets = stream_socket_pair( STREAM_PF_UNIX, STREAM_SOCK_STREAM, STREAM_IPPROTO_IP );
 			// Do the fork
 			$pid = pcntl_fork();
-			if ( $pid === -1 || $pid === false ) {
+			if ( $pid === -1 ) {
 				echo "Error creating child processes\n";
 				exit( 1 );
 			}

includes/ResourceLoader/Image.php

@@ -357,7 +357,7 @@ class Image {
 		// Reattach all direct children of the `<svg>` root node to the `<g>` wrapper
 		while ( $root->firstChild ) {
 			$node = $root->firstChild;
-			// @phan-suppress-next-line PhanUndeclaredProperty False positive
+			'@phan-var \DOMElement $node'; /** @var \DOMElement $node */
 			if ( !$titleNode && $node->nodeType === XML_ELEMENT_NODE && $node->tagName === 'title' ) {
 				// Remember the first encountered `<title>` node
 				$titleNode = $node;

includes/ResourceLoader/VueComponentParser.php

@@ -91,7 +91,7 @@ class VueComponentParser {
 		$template = $this->getTemplateHtml( $html, $options['minifyTemplate'] ?? false );
 
 		return [
-			'script' => trim( $nodes['script']->nodeValue ),
+			'script' => trim( $nodes['script']->nodeValue ?? '' ),
 			'template' => $template,
 			'style' => $styleData ? $styleData['style'] : null,
 			'styleLang' => $styleData ? $styleData['lang'] : null
@@ -160,7 +160,7 @@ class VueComponentParser {
 	 * @throws Exception If an invalid language is used, or if the 'scoped' attribute is set.
 	 */
 	private function getStyleAndLang( DOMElement $styleNode ): array {
-		$style = trim( $styleNode->nodeValue );
+		$style = trim( $styleNode->nodeValue ?? '' );
 		$styleLang = $styleNode->hasAttribute( 'lang' ) ?
 			$styleNode->getAttribute( 'lang' ) : 'css';
 		if ( $styleLang !== 'css' && $styleLang !== 'less' ) {

includes/debug/logger/monolog/LegacyHandler.php

@@ -24,6 +24,7 @@ use LogicException;
 use MediaWiki\Logger\LegacyLogger;
 use Monolog\Handler\AbstractProcessingHandler;
 use Monolog\Logger;
+use Socket;
 use UnexpectedValueException;
 
 /**
@@ -62,7 +63,7 @@ class LegacyHandler extends AbstractProcessingHandler {
 
 	/**
 	 * Log sink
-	 * @var resource|null
+	 * @var Socket|resource|null
 	 */
 	protected $sink;
 
@@ -142,7 +143,6 @@ class LegacyHandler extends AbstractProcessingHandler {
 				$domain = AF_INET;
 			}
 
-			// @phan-suppress-next-line PhanTypeMismatchProperty False positive caused by PHP 8.0 resource transition
 			$this->sink = socket_create( $domain, SOCK_DGRAM, SOL_UDP );
 
 		} else {
@@ -216,7 +216,6 @@ class LegacyHandler extends AbstractProcessingHandler {
 			}
 
 			socket_sendto(
-				// @phan-suppress-next-line PhanTypeMismatchArgumentInternal False positive caused by PHP 8.0 transition
 				$this->sink,
 				$text,
 				strlen( $text ),
@@ -233,9 +232,7 @@ class LegacyHandler extends AbstractProcessingHandler {
 	public function close(): void {
 		if ( $this->sink ) {
 			if ( $this->useUdp() ) {
-				// @phan-suppress-next-line PhanTypeMismatchArgumentInternal
 				socket_close( $this->sink );
-
 			} else {
 				fclose( $this->sink );
 			}

includes/libs/objectcache/MemcachedPeclBagOStuff.php

@@ -208,7 +208,7 @@ class MemcachedPeclBagOStuff extends MemcachedBagOStuff {
 		$result = $this->client->set( $routeKey, $value, $this->fixExpiry( $exptime ) );
 		ScopedCallback::consume( $noReplyScope );
 
-		return ( $result === false && $this->client->getResultCode() === Memcached::RES_NOTSTORED )
+		return ( !$result && $this->client->getResultCode() === Memcached::RES_NOTSTORED )
 			// "Not stored" is always used as the mcrouter response with AllAsyncRoute
 			? true
 			: $this->checkResult( $key, $result );
@@ -235,7 +235,7 @@ class MemcachedPeclBagOStuff extends MemcachedBagOStuff {
 		$result = $this->client->delete( $routeKey );
 		ScopedCallback::consume( $noReplyScope );
 
-		return ( $result === false && $this->client->getResultCode() === Memcached::RES_NOTFOUND )
+		return ( !$result && $this->client->getResultCode() === Memcached::RES_NOTFOUND )
 			// "Not found" is counted as success in our interface
 			? true
 			: $this->checkResult( $key, $result );
@@ -379,7 +379,7 @@ class MemcachedPeclBagOStuff extends MemcachedBagOStuff {
 		// The PECL implementation uses multi-key "get"/"gets"; no need to pipeline.
 		// T257003: avoid Memcached::GET_EXTENDED; no tokens are needed and that requires "gets"
 		// https://github.com/libmemcached/libmemcached/blob/eda2becbec24363f56115fa5d16d38a2d1f54775/libmemcached/get.cc#L272
-		$resByRouteKey = $this->client->getMulti( $routeKeys ) ?: [];
+		$resByRouteKey = $this->client->getMulti( $routeKeys );
 
 		if ( is_array( $resByRouteKey ) ) {
 			$res = [];
@@ -390,7 +390,8 @@ class MemcachedPeclBagOStuff extends MemcachedBagOStuff {
 			$res = false;
 		}
 
-		return $this->checkResult( false, $res );
+		$res = $this->checkResult( false, $res );
+		return $res !== false ? $res : [];
 	}
 
 	protected function doSetMulti( array $data, $exptime = 0, $flags = 0 ) {

includes/libs/rdbms/database/DatabaseMysqli.php

@@ -196,7 +196,7 @@ class DatabaseMysqli extends DatabaseMysqlBase {
 	 */
 	public function lastErrno() {
 		if ( $this->conn instanceof mysqli ) {
-			return (int)$this->conn->errno;
+			return $this->conn->errno;
 		} else {
 			return mysqli_connect_errno();
 		}

includes/password/BcryptPassword.php

@@ -77,7 +77,7 @@ class BcryptPassword extends ParameterizedPassword {
 		$hash = crypt( $password,
 			sprintf( '$2y$%02d$%s', (int)$this->params['rounds'], $this->args[0] ) );
 
-		if ( !is_string( $hash ) || strlen( $hash ) <= 13 ) {
+		if ( strlen( $hash ) <= 13 ) {
 			throw new PasswordError( 'Error when hashing password.' );
 		}
 

includes/password/MWOldPassword.php

@@ -49,7 +49,7 @@ class MWOldPassword extends ParameterizedPassword {
 			$this->hash = md5( $plaintext );
 		}
 
-		if ( !is_string( $this->hash ) || strlen( $this->hash ) < 32 ) {
+		if ( strlen( $this->hash ) < 32 ) {
 			throw new PasswordError( 'Error when hashing password.' );
 		}
 	}

includes/password/MWSaltedPassword.php

@@ -45,7 +45,7 @@ class MWSaltedPassword extends ParameterizedPassword {
 
 		$this->hash = md5( $this->args[0] . '-' . md5( $plaintext ) );
 
-		if ( !is_string( $this->hash ) || strlen( $this->hash ) < 32 ) {
+		if ( strlen( $this->hash ) < 32 ) {
 			throw new PasswordError( 'Error when hashing password.' );
 		}
 	}

includes/password/Pbkdf2PasswordUsingHashExtension.php

@@ -44,6 +44,8 @@ class Pbkdf2PasswordUsingHashExtension extends AbstractPbkdf2Password {
 		int $length
 	): string {
 		$hash = hash_pbkdf2( $digestAlgo, $password, $salt, $rounds, $length, true );
+		// Note: this check is unnecessary in PHP 8.0+, since the warning cases
+		// were all converted to exceptions
 		if ( !is_string( $hash ) ) {
 			throw new PasswordError( 'Error when hashing password.' );
 		}

includes/preferences/DefaultPreferencesFactory.php

@@ -1505,8 +1505,10 @@ class DefaultPreferencesFactory implements PreferencesFactory {
 				$thumbNamespaces
 			)
 		);
-		$defaultThumbNamespacesFormatted = (array)array_intersect_key( $thumbNamespacesFormatted, [ NS_FILE => 1 ] );
-		$extraThumbNamespacesFormatted = (array)array_diff_key( $thumbNamespacesFormatted, [ NS_FILE => 1 ] );
+		$defaultThumbNamespacesFormatted =
+			array_intersect_key( $thumbNamespacesFormatted, [ NS_FILE => 1 ] ) ?? [];
+		$extraThumbNamespacesFormatted =
+			array_diff_key( $thumbNamespacesFormatted, [ NS_FILE => 1 ] );
 		if ( $extraThumbNamespacesFormatted ) {
 			$defaultPreferences['search-thumbnail-extra-namespaces'] = [
 				'type' => 'toggle',

includes/search/searchwidgets/FullSearchResultWidget.php

@@ -399,7 +399,7 @@ class FullSearchResultWidget implements SearchResultWidget {
 		// we'll only deal with width from now on since conventions for
 		// standard sizes have formed around width; height will simply
 		// follow according to aspect ratio
-		$rescaledWidth = round( $rescaleCoefficient * $thumbnail->getWidth() );
+		$rescaledWidth = (int)round( $rescaleCoefficient * $thumbnail->getWidth() );
 
 		// we'll also be looking at $wgThumbLimits to ensure that we pick
 		// from within the predefined list of sizes

includes/specials/SpecialWatchlist.php

@@ -824,7 +824,7 @@ class SpecialWatchlist extends ChangesListSpecialPage {
 		] ) );
 		asort( $hours );
 
-		$select = new XmlSelect( 'days', 'days', (float)( $selectedHours / 24 ) );
+		$select = new XmlSelect( 'days', 'days', $selectedHours / 24 );
 
 		foreach ( $hours as $value ) {
 			if ( $value < 24 ) {

includes/xml/Xml.php

@@ -183,7 +183,7 @@ class Xml {
 			$timestamp = MWTimestamp::getInstance();
 			$thisMonth = intval( $timestamp->format( 'n' ) );
 			$thisYear = intval( $timestamp->format( 'Y' ) );
-			if ( intval( $encMonth ) > $thisMonth ) {
+			if ( $encMonth > $thisMonth ) {
 				$thisYear--;
 			}
 			$encYear = $thisYear;