Atomically write cache files (#674)

[etc/vim.git] / blib2to3 / pgen2 / grammar.py

diff --git a/blib2to3/pgen2/grammar.py b/blib2to3/pgen2/grammar.py
index a1da546eee20e12fc29d442835d80bea6379e40c..b20b9236b212d2886bbf986b90db1139afddae5e 100644 (file)
--- a/blib2to3/pgen2/grammar.py
+++ b/blib2to3/pgen2/grammar.py
@@ -13,7 +13,9 @@ fallback token code OP, but the parser needs the actual token code.
 """
 
 # Python imports
+import os.path
 import pickle
+import tempfile
 
 # Local imports
 from . import token
@@ -86,8 +88,9 @@ class Grammar(object):
 
     def dump(self, filename):
         """Dump the grammar tables to a pickle file."""
-        with open(filename, "wb") as f:
+        with tempfile.NamedTemporaryFile(dir=os.path.dirname(filename), delete=False) as f:
             pickle.dump(self.__dict__, f, pickle.HIGHEST_PROTOCOL)
+        os.replace(f.name, filename)
 
     def load(self, filename):
         """Load the grammar tables from a pickle file."""