Add various null checks when null is not possible to use as argument

Also check for false if needed

Found by phan strict checks

Change-Id: I298204653dfb788515a87978dd8705b6e4f9c775

includes/CategoryViewer.php

@@ -203,9 +203,17 @@ class CategoryViewer extends ContextSource {
 	 * @param int $pageLength
 	 */
 	public function addSubcategoryObject( Category $cat, $sortkey, $pageLength ) {
+		$page = $cat->getPage();
+		if ( !$page ) {
+			return;
+		}
+
 		// Subcategory; strip the 'Category' namespace from the link text.
 		$pageRecord = MediaWikiServices::getInstance()->getPageStore()
-			->getPageByReference( $cat->getPage() );
+			->getPageByReference( $page );
+		if ( !$pageRecord ) {
+			return;
+		}
 
 		$this->children[] = $this->generateLink(
 			'subcat',
@@ -215,7 +223,7 @@ class CategoryViewer extends ContextSource {
 		);
 
 		$this->children_start_char[] =
-			$this->getSubcategorySortChar( $cat->getPage(), $sortkey );
+			$this->getSubcategorySortChar( $page, $sortkey );
 	}
 
 	/**

includes/CommentFormatter/CommentParser.php

@@ -384,7 +384,7 @@ class CommentParser {
 					if ( isset( $match[1][0] ) && $match[1][0] == ':' ) {
 						$match[1] = substr( $match[1], 1 );
 					}
-					if ( $match[1] !== false && $match[1] !== '' ) {
+					if ( $match[1] !== false && $match[1] !== null && $match[1] !== '' ) {
 						if ( preg_match(
 							$this->contLang->linkTrail(),
 							$match[3],

includes/OutputPage.php

@@ -3157,7 +3157,7 @@ class OutputPage extends ContextSource {
 					$module = $rl->getModule( $name );
 					if ( $module ) {
 						$group = $module->getGroup();
-						if ( isset( $exemptGroups[$group] ) ) {
+						if ( $group !== null && isset( $exemptGroups[$group] ) ) {
 							// The `noscript` module is excluded from the client
 							// side registry, no need to set its state either.
 							// But we still output it. See T291735

includes/StreamFile.php

@@ -121,7 +121,7 @@ class StreamFile {
 			) {
 				return 'unknown/unknown';
 			}
-			if ( $verifyMimeType && in_array( strtolower( $type ), $mimeTypeExclusions ) ) {
+			if ( $verifyMimeType && $type !== null && in_array( strtolower( $type ), $mimeTypeExclusions ) ) {
 				return 'unknown/unknown';
 			}
 		}

includes/htmlform/fields/HTMLUsersMultiselectField.php

@@ -33,6 +33,7 @@ class HTMLUsersMultiselectField extends HTMLUserTextField {
 		$userNameUtils = MediaWikiServices::getInstance()->getUserNameUtils();
 		$listOfIps = [];
 		foreach ( $usersArray as $user ) {
+			$canonicalUser = false;
 			if ( IPUtils::isIPAddress( $user ) ) {
 				$parsedIPRange = IPUtils::parseRange( $user );
 				if ( !in_array( $parsedIPRange, $listOfIps ) ) {
@@ -42,7 +43,9 @@ class HTMLUsersMultiselectField extends HTMLUserTextField {
 			} else {
 				$canonicalUser = $userNameUtils->getCanonical( $user, UserNameUtils::RIGOR_NONE );
 			}
-			$normalizedUsers[] = $canonicalUser;
+			if ( $canonicalUser !== false ) {
+				$normalizedUsers[] = $canonicalUser;
+			}
 		}
 		// Remove any duplicate usernames
 		$uniqueUsers = array_unique( $normalizedUsers );

includes/libs/mime/MimeAnalyzer.php

@@ -490,7 +490,7 @@ class MimeAnalyzer implements LoggerAwareInterface {
 			$callback( $this, $ext, $mime /* by reference */ );
 		}
 
-		if ( isset( $this->mimeTypeAliases[$mime] ) ) {
+		if ( $mime !== null && isset( $this->mimeTypeAliases[$mime] ) ) {
 			$mime = $this->mimeTypeAliases[$mime];
 		}
 

includes/page/ImagePage.php

@@ -607,7 +607,7 @@ EOT
 			}
 
 			$renderLangOptions = $this->displayImg->getAvailableLanguages();
-			if ( count( $renderLangOptions ) >= 1 ) {
+			if ( $renderLang !== null && count( $renderLangOptions ) >= 1 ) {
 				$out->addHTML( $this->doRenderLangOpt( $renderLangOptions, $renderLang ) );
 			}
 

includes/specials/SpecialAllPages.php

@@ -171,15 +171,15 @@ class SpecialAllPages extends IncludableSpecialPage {
 
 	/**
 	 * @param int $namespace (default NS_MAIN)
-	 * @param string $from List all pages from this name
-	 * @param string $to List all pages to this name
+	 * @param string|null $from List all pages from this name
+	 * @param string|null $to List all pages to this name
 	 * @param bool $hideredirects Don't show redirects (default false)
 	 */
 	private function showToplevel(
-		$namespace = NS_MAIN, $from = '', $to = '', $hideredirects = false
+		$namespace = NS_MAIN, $from = null, $to = null, $hideredirects = false
 	) {
-		$from = Title::makeTitleSafe( $namespace, $from );
-		$to = Title::makeTitleSafe( $namespace, $to );
+		$from = $from ? Title::makeTitleSafe( $namespace, $from ) : null;
+		$to = $to ? Title::makeTitleSafe( $namespace, $to ) : null;
 		$from = ( $from && $from->isLocal() ) ? $from->getDBkey() : null;
 		$to = ( $to && $to->isLocal() ) ? $to->getDBkey() : null;
 

includes/specials/SpecialVersion.php

@@ -872,7 +872,7 @@ class SpecialVersion extends SpecialPage {
 			$licenseName = null;
 			if ( isset( $extension['license-name'] ) ) {
 				$licenseName = new HtmlArmor( $out->parseInlineAsInterface( $extension['license-name'] ) );
-			} elseif ( ExtensionInfo::getLicenseFileNames( $extensionPath ) ) {
+			} elseif ( $extensionPath !== null && ExtensionInfo::getLicenseFileNames( $extensionPath ) ) {
 				$licenseName = $this->msg( 'version-ext-license' )->text();
 			}
 			if ( $licenseName !== null ) {