Move attrs and attr endings to static variable level, double escape s…

…lash in $attr_endings and add more tests (courtesy of Juliette)

WordPressVIPMinimum/Sniffs/Security/ProperEscapingFunctionSniff.php

@@ -49,6 +49,30 @@ class ProperEscapingFunctionSniff extends Sniff {
 		T_COMMA              => T_COMMA,
 	];
 
+	/**
+	 * List of attributes associated with url outputs.
+	 * 
+	 * @var array
+	 */
+	private $url_attrs = [
+		'href',
+		'src',
+		'url',
+		'action',
+	];
+
+	/**
+	 * List of syntaxes for inside attribute detection. 
+	 * 
+	 * @var array
+	 */
+	private $attr_endings = [
+		'="',
+		"='",
+		"=\\'",
+		'=\\"',
+	];
+
 	/**
 	 * Returns an array of tokens this test wants to listen for.
 	 *
@@ -75,7 +99,7 @@ public function process_token( $stackPtr ) {
 
 		$html = $this->phpcsFile->findPrevious( $this->echo_or_concat_tokens, $stackPtr - 1, null, true );
 
-		// Use $textStringTokens b/c heredoc and nowdoc tokens will never be encountered in this context anyways.
+		// Use $textStringTokens b/c heredoc and nowdoc tokens shouldn't be matched anyways.
 		if ( $html === false || isset( Tokens::$textStringTokens[ $this->tokens[ $html ]['code'] ] ) === false ) {
 			return;
 		}
@@ -118,13 +142,8 @@ public function process_token( $stackPtr ) {
 	 */
 	public function attr_expects_url( $content ) {
 		$attr_expects_url = false;
-		foreach ( [ 'href', 'src', 'url', 'action' ] as $attr ) {
-			foreach ( [
-				'="',
-				"='",
-				'=\'"', // The tokenizer does some fun stuff when it comes to mixing double and single quotes.
-				'="\'', // The tokenizer does some fun stuff when it comes to mixing double and single quotes.
-			] as $ending ) {
+		foreach ( $this->url_attrs as $attr ) {
+			foreach ( $this->attr_endings as $ending ) {
 				if ( $this->endswith( $content, $attr . $ending ) === true ) {
 					$attr_expects_url = true;
 					break;
@@ -143,12 +162,7 @@ public function attr_expects_url( $content ) {
 	 */
 	public function is_html_attr( $content ) {
 		$is_html_attr = false;
-		foreach ( [
-			'="',
-			"='",
-			'=\'"', // The tokenizer does some fun stuff when it comes to mixing double and single quotes.
-			'="\'', // The tokenizer does some fun stuff when it comes to mixing double and single quotes.
-		] as $ending ) {
+		foreach ( $this->attr_endings as $ending ) {
 			if ( $this->endswith( $content, $ending ) === true ) {
 				$is_html_attr = true;
 				break;
@@ -158,12 +172,12 @@ public function is_html_attr( $content ) {
 	}
 
 	/**
-	 * Tests whether string ends with opening HTML tag for detection in attribute escaping.
+	 * Tests whether escaping function is being used outside of HTML tag.
 	 *
-	 * @param string $function_name Name of function.
-	 * @param string $content       Haystack where we look for the end of opening HTML tag.
+	 * @param string $function_name Escaping function.
+	 * @param string $content       Haystack where we look for the end of a HTML tag.
 	 *
-	 * @return bool True if escaping attribute function and string ends with opening HTML tag.
+	 * @return bool True if escaping attribute function and string ends with a HTML tag.
 	 */
 	public function is_outside_html_attr_context( $function_name, $content ) {
 		return $this->escaping_functions[ $function_name ] === 'attr' && $this->endswith( trim( $content ), '>' );

WordPressVIPMinimum/Tests/Security/ProperEscapingFunctionUnitTest.inc

@@ -68,6 +68,13 @@ echo "<$tag>  " , esc_attr( $test ) , "</$tag>"; // Error.
 <div><?= esc_attr($attr) ?></div><!-- Error -->
 <div><?php esc_attr_e($attr) ?></div><!-- Error -->
 <div data-tag="<?= esc_attr( $attr ); ?>"> <!-- OK -->
-<?php echo "<div> {$test} </div>"; // OK.
+<?php echo "<div>" . $test . "</div>"; // OK.
 echo "<{$tag}>" . esc_attr( $tag_content ) . "</{$tag}>"; // Error.
 echo "<$tag" . '   >' . esc_attr( $tag_content ) . "</$tag>"; // Error.
+echo '<div class=\'' . esc_html($class) . '\'>'; // Error.
+echo "<div class=\"" . esc_html($class) . '">'; // Error.
+echo "<div $someAttribute class=\"" . esc_html($class) . '">'; // Error.
+echo '<a href=\'' . esc_html($url) . '\'>'; // Error.
+echo "<img src=\"" . esc_html($src) . '"/>'; // Error.
+echo "<div $someAttributeName-url=\"" . esc_html($url) . '">'; // Error.
+echo '<a href="',  esc_html($url), '">'; // Error.

WordPressVIPMinimum/Tests/Security/ProperEscapingFunctionUnitTest.php

@@ -45,6 +45,13 @@ public function getErrorList() {
 			69 => 1,
 			72 => 1,
 			73 => 1,
+			74 => 1,
+			75 => 1,
+			76 => 1,
+			77 => 1,
+			78 => 1,
+			79 => 1,
+			80 => 1,
 		];
 	}