Use native str_starts_with/str_contains and such where possible

Includes a few other smaller cleanups that aren't worth a separate
patch, in my opinion.

Change-Id: I42d6e70ef132bfc2cf606164e2e62becb1f915df

src/MathLaTeXML.php

@@ -92,7 +92,7 @@ class MathLaTeXML extends MathMathML {
 
 		// There is an API-inconsistency between different versions of the LaTeXML daemon
 		// some versions require the literal prefix other don't allow it.
-		if ( !strpos( $this->host, '/convert' ) ) {
+		if ( !str_contains( $this->host, '/convert' ) ) {
 			$postData = preg_replace( '/&tex=/', '&tex=literal:', $postData, 1 );
 		}
 

src/WikiTexVC/Mhchem/MhchemPatterns.php

@@ -85,21 +85,13 @@ class MhchemPatterns {
 		 */
 		if ( !$pattern instanceof Reg ) {
 			// Added this if to catch empty needle for strpos input  in PHP
-			if ( !MhchemUtil::issetJS( $pattern ) ) {
+			if ( !MhchemUtil::issetJS( $pattern ) || str_starts_with( $input, $pattern ) ) {
 				return $pattern;
 			}
-			if ( strpos( $input, $pattern ) !== 0 ) {
-				return null;
-			}
-			return $pattern;
-		} else {
-			$matches = [];
-			$match = preg_match( $pattern->getRegExp(), $input, $matches );
-			if ( !$match ) {
-				return null;
-			}
+		} elseif ( preg_match( $pattern->getRegExp(), $input, $matches ) ) {
 			return $matches[0];
 		}
+		return null;
 	}
 
 	private function findObserveGroupsInner( string $input, $i, $endChars ): ?array {

src/WikiTexVC/TexVC.php

@@ -31,10 +31,6 @@ class TexVC {
 		$this->tu = TexUtil::getInstance();
 	}
 
-	private function strStartsWith( $haystack, $needle ): bool {
-		return strpos( $haystack, $needle ) === 0;
-	}
-
 	/**
 	 * Usually this step is done implicitly within the check-method.
 	 * @param string $input tex-string as input for the grammar
@@ -139,8 +135,8 @@ class TexVC {
 			return $result;
 		} catch ( Exception $ex ) {
 			if ( $ex instanceof SyntaxError && !$options['oldtexvc']
-					&& $this->strStartsWith( $ex->getMessage(), 'Deprecation' ) ) {
-
+				&& str_starts_with( $ex->getMessage(), 'Deprecation' )
+			) {
 				$warnings[] = [
 					'type' => 'texvc-deprecation',
 					'details' => $this->handleTexError( $ex, $options )

tests/phpunit/integration/MathIntegrationTest.php

@@ -2,6 +2,7 @@
 namespace MediaWiki\Extension\Math\Tests;
 
 use MediaWiki\Extension\Math\Math;
+use MediaWiki\Extension\Math\MathConfig;
 
 /**
  * @covers \MediaWiki\Extension\Math\Math
@@ -9,6 +10,6 @@ use MediaWiki\Extension\Math\Math;
 class MathIntegrationTest extends \MediaWikiIntegrationTestCase {
 	public function testGetMathConfigNull() {
 		$config = Math::getMathConfig();
-		$this->assertInstanceOf( '\MediaWiki\Extension\Math\MathConfig', $config );
+		$this->assertInstanceOf( MathConfig::class, $config );
 	}
 }