Issue #2901998 by vaplas, damiankloip, kim.pepper: File size of 0 is not set...

Issue #2901998 by vaplas, damiankloip, kim.pepper: File size of 0 is not set when file entities are saved

core/modules/file/src/Entity/File.php

@@ -190,7 +190,10 @@ public function preSave(EntityStorageInterface $storage) {
 
     // The file itself might not exist or be available right now.
     $uri = $this->getFileUri();
-    if ($size = @filesize($uri)) {
+    $size = @filesize($uri);
+
+    // Set size unless there was an error.
+    if ($size !== FALSE) {
       $this->setSize($size);
     }
   }

core/modules/file/tests/src/Kernel/SaveTest.php

@@ -81,6 +81,22 @@ public function testFileSave() {
     $this->assertEqual(1, count($fids));
     $this->assertEqual([$uppercase_file->id() => $uppercase_file->id()], $fids);
 
+    // Save a file with zero bytes.
+    $file = File::create([
+      'uid' => 1,
+      'filename' => 'no-druplicon.txt',
+      'uri' => 'public://no-druplicon.txt',
+      'filemime' => 'text/plain',
+      'status' => FILE_STATUS_PERMANENT,
+    ]);
+
+    file_put_contents($file->getFileUri(), '');
+
+    // Save it, inserting a new record.
+    $file->save();
+
+    // Check the file size was set to zero.
+    $this->assertSame(0, $file->getSize());
   }
 
 }