Media: Bail early if image is already the requested size.

In `WP_Image_Editor_Imagick`, bail early in `make_subsize()` if the image is already the requested size. Previously, `make_subsize()` would create another copy of the file. `WP_Image_Editor_GD` doesn't have the same problem.

Props wojtekn, danielbachhuber.
Fixes #57370.


git-svn-id: https://develop.svn.wordpress.org/trunk@55278 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/media.php

@@ -3770,6 +3770,40 @@ EOF;
 		}
 	}
 
+	/**
+	 * Test that an image size isn't generated if it matches the original image size.
+	 */
+	public function test_wp_generate_attachment_metadata_doesnt_generate_sizes_for_150_square_image() {
+		$temp_dir = get_temp_dir();
+		$file     = $temp_dir . '/test-square-150.jpg';
+		copy( DIR_TESTDATA . '/images/test-square-150.jpg', $file );
+
+		$attachment_id = self::factory()->attachment->create_object(
+			array(
+				'post_mime_type' => 'image/jpeg',
+				'file'           => $file,
+			)
+		);
+
+		$metadata = wp_generate_attachment_metadata( $attachment_id, $file );
+		$this->assertEquals(
+			array(),
+			$metadata['sizes']
+		);
+		$this->assertEquals(
+			'test-square-150.jpg',
+			basename( $metadata['file'] )
+		);
+		$this->assertEquals(
+			'150',
+			$metadata['width']
+		);
+		$this->assertEquals(
+			'150',
+			$metadata['height']
+		);
+	}
+
 	/**
 	 * Add threshold to create a `-scaled` output image for testing.
 	 */