Issue #21729: Used the "with" statement in the dbm.dumb module to ensure

files closing.  Patch by Claudiu Popa.

Lib/dumbdbm.py

@@ -68,8 +68,9 @@ class _Database(UserDict.DictMixin):
         try:
             f = _open(self._datfile, 'r')
         except IOError:
-            f = _open(self._datfile, 'w')
+            with _open(self._datfile, 'w') as f:
                 self._chmod(self._datfile)
+        else:
             f.close()
         self._update()
 
@@ -81,11 +82,11 @@ class _Database(UserDict.DictMixin):
         except IOError:
             pass
         else:
+            with f:
                 for line in f:
                     line = line.rstrip()
                     key, pos_and_siz_pair = eval(line)
                     self._index[key] = pos_and_siz_pair
-            f.close()
 
     # Write the index dict to the directory file.  The original directory
     # file (if any) is renamed with a .bak extension first.  If a .bak
@@ -107,20 +108,18 @@ class _Database(UserDict.DictMixin):
         except self._os.error:
             pass
 
-        f = self._open(self._dirfile, 'w')
+        with self._open(self._dirfile, 'w') as f:
             self._chmod(self._dirfile)
             for key, pos_and_siz_pair in self._index.iteritems():
                 f.write("%r, %r\n" % (key, pos_and_siz_pair))
-        f.close()
 
     sync = _commit
 
     def __getitem__(self, key):
         pos, siz = self._index[key]     # may raise KeyError
-        f = _open(self._datfile, 'rb')
+        with _open(self._datfile, 'rb') as f:
             f.seek(pos)
             dat = f.read(siz)
-        f.close()
         return dat
 
     # Append val to the data file, starting at a _BLOCKSIZE-aligned
@@ -128,14 +127,13 @@ class _Database(UserDict.DictMixin):
     # to get to an aligned offset.  Return pair
     #     (starting offset of val, len(val))
     def _addval(self, val):
-        f = _open(self._datfile, 'rb+')
+        with _open(self._datfile, 'rb+') as f:
             f.seek(0, 2)
             pos = int(f.tell())
             npos = ((pos + _BLOCKSIZE - 1) // _BLOCKSIZE) * _BLOCKSIZE
             f.write('\0'*(npos-pos))
             pos = npos
             f.write(val)
-        f.close()
         return (pos, len(val))
 
     # Write val to the data file, starting at offset pos.  The caller
@@ -143,10 +141,9 @@ class _Database(UserDict.DictMixin):
     # pos to hold val, without overwriting some other value.  Return
     # pair (pos, len(val)).
     def _setval(self, pos, val):
-        f = _open(self._datfile, 'rb+')
+        with _open(self._datfile, 'rb+') as f:
             f.seek(pos)
             f.write(val)
-        f.close()
         return (pos, len(val))
 
     # key is a new key whose associated value starts in the data file
@@ -154,10 +151,9 @@ class _Database(UserDict.DictMixin):
     # the in-memory index dict, and append one to the directory file.
     def _addkey(self, key, pos_and_siz_pair):
         self._index[key] = pos_and_siz_pair
-        f = _open(self._dirfile, 'a')
+        with _open(self._dirfile, 'a') as f:
             self._chmod(self._dirfile)
             f.write("%r, %r\n" % (key, pos_and_siz_pair))
-        f.close()
 
     def __setitem__(self, key, val):
         if not type(key) == type('') == type(val):

Misc/NEWS

@@ -32,6 +32,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #21729: Used the "with" statement in the dbm.dumb module to ensure
+  files closing.
+
 - Issue #21672: Fix the behavior of ntpath.join on UNC-style paths.
 
 - Issue #19145:  The times argument for itertools.repeat now handles