[Filesystem] Improve exception message for copy method

Author: King2500

src/Symfony/Component/Filesystem/Filesystem.php

@@ -72,8 +72,8 @@ public function copy($originFile, $targetFile, $override = false)
             // Like `cp`, preserve executable permission bits
             @chmod($targetFile, fileperms($targetFile) | (fileperms($originFile) & 0111));
 
-            if (stream_is_local($originFile) && $bytesCopied !== filesize($originFile)) {
-                throw new IOException(sprintf('Failed to copy the whole content of "%s" to "%s %g bytes copied".', $originFile, $targetFile, $bytesCopied), 0, null, $originFile);
+            if (stream_is_local($originFile) && $bytesCopied !== ($bytesOrigin = filesize($originFile))) {
+                throw new IOException(sprintf('Failed to copy the whole content of "%s" to "%s" (%g of %g bytes copied).', $originFile, $targetFile, $bytesCopied, $bytesOrigin), 0, null, $originFile);
             }
         }
     }