Replace strlen() calls with strict string comparisons

Note there is an important difference between the two ways to express
this: strlen() does a string cast, but the `=== ''` and `!== ''`
comparisons will only detect empty strings, but not null, false, or any
other falsy value that becomes an empty string when cast to be one.

I am only touching code where I'm sure the variable is guaranteed to be
a string.

This change is done because I find the strict comparisons much more
readable. The code does exactly one thing now, and no magic casts any
more.

Change-Id: I3e908a0c7c7b6c29b0e5a1414f2ba9062a215b93

includes/MovePage.php

@@ -106,7 +106,7 @@ class MovePage {
 
 		$oldid = $this->oldTitle->getArticleID();
 
-		if ( strlen( $this->newTitle->getDBkey() ) < 1 ) {
+		if ( $this->newTitle->getDBkey() === '' ) {
 			$status->fatal( 'articleexists' );
 		}
 		if (

includes/SiteConfiguration.php

@@ -562,7 +562,7 @@ class SiteConfiguration {
 				->execute();
 
 			$data = trim( $result->getStdout() );
-			if ( $result->getExitCode() != 0 || !strlen( $data ) ) {
+			if ( $result->getExitCode() || $data === '' ) {
 				throw new MWException( "Failed to run getConfiguration.php: {$result->getStdout()}" );
 			}
 			$res = unserialize( $data );

includes/api/ApiQuerySiteinfo.php

@@ -664,8 +664,8 @@ class ApiQuerySiteinfo extends ApiQueryBase {
 		}
 
 		$data = [
-			'url' => strlen( $url ) ? $url : '',
-			'text' => strlen( $text ) ? $text : '',
+			'url' => (string)$url,
+			'text' => (string)$text,
 		];
 
 		return $this->getResult()->addValue( 'query', $property, $data );

includes/content/WikiTextStructure.php

@@ -154,7 +154,7 @@ class WikiTextStructure {
 			'enableSectionEditTokens' => false,
 			'allowTOC' => false,
 		] );
-		if ( strlen( $text ) == 0 ) {
+		if ( $text === '' ) {
 			$this->allText = "";
 			// empty text - nothing to seek here
 			return;

includes/http/PhpHttpRequest.php

@@ -217,7 +217,7 @@ class PhpHttpRequest extends MWHttpRequest {
 					break;
 				}
 
-				if ( strlen( $buf ) ) {
+				if ( $buf !== '' ) {
 					call_user_func( $this->callback, $fh, $buf );
 				}
 			}

includes/jobqueue/jobs/ThumbnailRenderJob.php

@@ -93,7 +93,7 @@ class ThumbnailRenderJob extends Job {
 		if ( $wgUploadThumbnailRenderHttpCustomDomain ) {
 			$parsedUrl = wfParseUrl( $thumbUrl );
 
-			if ( !$parsedUrl || !isset( $parsedUrl['path'] ) || !strlen( $parsedUrl['path'] ) ) {
+			if ( !isset( $parsedUrl['path'] ) || $parsedUrl['path'] === '' ) {
 				$this->setLastError( __METHOD__ . ": invalid thumb URL: $thumbUrl" );
 				return false;
 			}

includes/libs/rdbms/database/DatabaseDomain.php

@@ -42,11 +42,11 @@ class DatabaseDomain {
 	 * @param string $prefix Table prefix
 	 */
 	public function __construct( $database, $schema, $prefix ) {
-		if ( $database !== null && ( !is_string( $database ) || !strlen( $database ) ) ) {
+		if ( $database !== null && ( !is_string( $database ) || $database === '' ) ) {
 			throw new InvalidArgumentException( 'Database must be null or a non-empty string.' );
 		}
 		$this->database = $database;
-		if ( $schema !== null && ( !is_string( $schema ) || !strlen( $schema ) ) ) {
+		if ( $schema !== null && ( !is_string( $schema ) || $schema === '' ) ) {
 			throw new InvalidArgumentException( 'Schema must be null or a non-empty string.' );
 		}
 		$this->schema = $schema;

includes/specials/SpecialSearch.php

@@ -102,7 +102,7 @@ class SpecialSearch extends SpecialPage {
 	/**
 	 * Entry point
 	 *
-	 * @param string $par
+	 * @param string|null $par
 	 */
 	public function execute( $par ) {
 		$request = $this->getRequest();
@@ -115,7 +115,7 @@ class SpecialSearch extends SpecialPage {
 		// parameter, but also as part of the primary url. This can have PII implications
 		// in releasing page view data. As such issue a 301 redirect to the correct
 		// URL.
-		if ( strlen( $par ) && !strlen( $term ) ) {
+		if ( $par !== null && $par !== '' && $term === '' ) {
 			$query = $request->getValues();
 			unset( $query['title'] );
 			// Strip underscores from title parameter; most of the time we'll want