commit - 961a01165a7e91f60f80376335345461759cb88b
commit + dcdafdf7db10d59342377a05c8083f2ddb9de664
blob - d5f02012c16399ed7e624f2a6bdb17f665a24805
blob + 11060542743e7684288e3889156c3ca7ff92bc99
--- dulwich/file.py
+++ dulwich/file.py
@@ -22,6 +22,7 @@
 
 import os
 import sys
+import warnings
 
 
 def ensure_dir_exists(dirname):
@@ -202,6 +203,11 @@ class _GitFile:
         finally:
             self.abort()
 
+    def __del__(self):
+        if not getattr(self, '_closed', True):
+            warnings.warn('unclosed %r' % self, ResourceWarning, stacklevel=2)
+            self.abort()
+
     def __enter__(self):
         return self