Media: Fix handling of multibyte exif description metadata.

The exif standards expect the UserComment field to be used as a substitute for ImageDescription if multibyte characters are needed. WordPress media only mapped the ImageDescription field and did not correctly handle descriptions with multibyte characters.

Fix metadata saving to better handle media with multibyte characters in metadata and update unit tests.

Props fotodrachen, antpb, joedolson, mikinc860, azaozz, nicolefurlan.
Fixes #58082.

git-svn-id: https://develop.svn.wordpress.org/trunk@57267 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/image.php

@@ -863,22 +863,51 @@ function wp_read_image_metadata( $file ) {
 			$exif = array();
 		}
 
+		$exif_description = '';
+		$exif_usercomment = '';
 		if ( ! empty( $exif['ImageDescription'] ) ) {
+			$exif_description = trim( $exif['ImageDescription'] );
+		}
+
+		if ( ! empty( $exif['COMPUTED']['UserComment'] ) ) {
+			$exif_usercomment = trim( $exif['COMPUTED']['UserComment'] );
+		}
+
+		if ( $exif_description ) {
 			mbstring_binary_safe_encoding();
-			$description_length = strlen( $exif['ImageDescription'] );
+			$description_length = strlen( $exif_description );
 			reset_mbstring_encoding();
-
 			if ( empty( $meta['title'] ) && $description_length < 80 ) {
 				// Assume the title is stored in ImageDescription.
-				$meta['title'] = trim( $exif['ImageDescription'] );
+				$meta['title'] = $exif_description;
 			}
 
-			if ( empty( $meta['caption'] ) && ! empty( $exif['COMPUTED']['UserComment'] ) ) {
-				$meta['caption'] = trim( $exif['COMPUTED']['UserComment'] );
+			// If both user comments and description are present.
+			if ( empty( $meta['caption'] ) && $exif_description && $exif_usercomment ) {
+				if ( ! empty( $meta['title'] ) && $exif_description === $meta['title'] ) {
+					$caption = $exif_usercomment;
+				} else {
+					if ( $exif_description === $exif_usercomment ) {
+						$caption = $exif_description;
+					} else {
+						$caption = trim( $exif_description . ' ' . $exif_usercomment );
+					}
+				}
+				$meta['caption'] = $caption;
+			}
+
+			if ( empty( $meta['caption'] ) && $exif_usercomment ) {
+				$meta['caption'] = $exif_usercomment;
 			}
 
 			if ( empty( $meta['caption'] ) ) {
-				$meta['caption'] = trim( $exif['ImageDescription'] );
+				$meta['caption'] = $exif_description;
+			}
+		} elseif ( empty( $meta['caption'] ) && $exif_usercomment ) {
+			$meta['caption']    = $exif_usercomment;
+			$description_length = strlen( $exif_usercomment );
+			if ( empty( $meta['title'] ) && $description_length < 80 ) {
+				$meta['title'] = trim( $exif_usercomment );
 			}
 		} elseif ( empty( $meta['caption'] ) && ! empty( $exif['Comments'] ) ) {
 			$meta['caption'] = trim( $exif['Comments'] );

tests/phpunit/tests/image/meta.php

@@ -51,13 +51,13 @@ public function test_exif_d70_mf() {
 		$this->assertSame( '0', $out['aperture'], 'Aperture value not the same' );
 		$this->assertSame( '', $out['credit'], 'Credit value not the same' );
 		$this->assertSame( 'NIKON D70', $out['camera'], 'Camera value not the same' );
-		$this->assertSame( '', $out['caption'], 'Caption value not the same' );
+		$this->assertSame( 'Copyright Alex Shiels', $out['caption'], 'Caption value not the same' );
 		$this->assertEquals( strtotime( '2007-06-17 21:18:00' ), $out['created_timestamp'], 'Timestamp value not equivalent' );
 		$this->assertSame( '', $out['copyright'], 'Copyright value not the same' );
 		$this->assertEquals( 0, $out['focal_length'], 'Focal length value not equivalent' );
 		$this->assertEquals( 0, $out['iso'], 'Iso value not equivalent' ); // Interesting - a Nikon bug?
 		$this->assertEquals( 1 / 500, $out['shutter_speed'], 'Shutter speed value not equivalent' );
-		$this->assertSame( '', $out['title'], 'Title value not the same' );
+		$this->assertSame( 'Copyright Alex Shiels', $out['title'], 'Title value not the same' );
 		// $this->assertSame( array( 'Flowers' ), $out['keywords'] );
 	}