Merge pull request #29454 from nextcloud/bugfix/noid/detect-mimetype-…

…by-content-only-with-content

Detect mimetype by content only with content

apps/workflowengine/lib/Check/FileMimeType.php

@@ -127,7 +127,7 @@ protected function getActualValue() {
 			return $this->cacheAndReturnMimeType($this->storage->getId(), $this->path, 'httpd/unix-directory');
 		}
 
-		if ($this->storage->file_exists($this->path)) {
+		if ($this->storage->file_exists($this->path) && $this->storage->filesize($this->path)) {
 			$path = $this->storage->getLocalFile($this->path);
 			$mimeType = $this->mimeTypeDetector->detectContent($path);
 			return $this->cacheAndReturnMimeType($this->storage->getId(), $this->path, $mimeType);