Merge pull request #196 from 10up/fix/fatal-error-when-filter-called-…

…with-less-args

Fix fatal error when "admin_post_thumbnail_html" filter is applied with null "$thumbnail_id" param

safe-svg.php

@@ -401,13 +401,13 @@ public function one_pixel_fix( $image, $attachment_id, $size, $icon ) {
 		/**
 		 * If the featured image is an SVG we wrap it in an SVG class so we can apply our CSS fix.
 		 *
-		 * @param string $content Admin post thumbnail HTML markup.
-		 * @param int    $post_id Post ID.
-		 * @param int    $thumbnail_id Thumbnail ID.
+		 * @param string   $content Admin post thumbnail HTML markup.
+		 * @param int      $post_id Post ID.
+		 * @param int|null $thumbnail_id Thumbnail attachment ID, or null if there isn't one.
 		 *
 		 * @return string
 		 */
-		public function featured_image_fix( $content, $post_id, $thumbnail_id ) {
+		public function featured_image_fix( $content, $post_id, $thumbnail_id = null ) {
 			$mime = get_post_mime_type( $thumbnail_id );
 
 			if ( 'image/svg+xml' === $mime ) {

tests/unit/test-safe-svg.php

@@ -341,5 +341,16 @@ public function test_featured_image_fix() {
 
 		$response = $this->instance->featured_image_fix( 'test', 1, 1 );
 		$this->assertSame( '<span class="svg">test</span>', $response );
+
+		\WP_Mock::userFunction(
+			'get_post_mime_type',
+			array(
+				'args'   => null,
+				'return' => false,
+			)
+		);
+
+		$response = $this->instance->featured_image_fix( 'test', 1 );
+		$this->assertSame( 'test', $response );
 	}
 }