Issue #28847: dbm.dumb now supports reading read-only files and no longer
writes the index file when it is not changed.
diff --git a/Lib/dbm/dumb.py b/Lib/dbm/dumb.py
index e7c6440..2296dbf 100644
--- a/Lib/dbm/dumb.py
+++ b/Lib/dbm/dumb.py
@@ -97,8 +97,9 @@
try:
f = _io.open(self._dirfile, 'r', encoding="Latin-1")
except OSError:
- pass
+ self._modified = not self._readonly
else:
+ self._modified = False
with f:
for line in f:
line = line.rstrip()
@@ -113,7 +114,7 @@
# CAUTION: It's vital that _commit() succeed, and _commit() can
# be called from __del__(). Therefore we must never reference a
# global in this routine.
- if self._index is None:
+ if self._index is None or not self._modified:
return # nothing to do
try:
@@ -197,6 +198,7 @@
elif not isinstance(val, (bytes, bytearray)):
raise TypeError("values must be bytes or strings")
self._verify_open()
+ self._modified = True
if key not in self._index:
self._addkey(key, self._addval(val))
else:
@@ -229,6 +231,7 @@
if isinstance(key, str):
key = key.encode('utf-8')
self._verify_open()
+ self._modified = True
# The blocks used by the associated value are lost.
del self._index[key]
# XXX It's unclear why we do a _commit() here (the code always
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index eb5a89a..09a02da 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -360,9 +360,9 @@
mode = 0
if stat.S_ISDIR(mode):
_waitfor(_rmtree_inner, fullname, waitall=True)
- _force_run(path, os.rmdir, fullname)
+ _force_run(fullname, os.rmdir, fullname)
else:
- _force_run(path, os.unlink, fullname)
+ _force_run(fullname, os.unlink, fullname)
_waitfor(_rmtree_inner, path, waitall=True)
_waitfor(lambda p: _force_run(p, os.rmdir, p), path)
else:
diff --git a/Lib/test/test_dbm_dumb.py b/Lib/test/test_dbm_dumb.py
index 2d77f07..df531d6 100644
--- a/Lib/test/test_dbm_dumb.py
+++ b/Lib/test/test_dbm_dumb.py
@@ -5,6 +5,7 @@
import io
import operator
import os
+import stat
import unittest
import warnings
import dbm.dumb as dumbdbm
@@ -259,6 +260,21 @@
f = dumbdbm.open(_fname, flag)
f.close()
+ @unittest.skipUnless(hasattr(os, 'chmod'), 'test needs os.chmod()')
+ def test_readonly_files(self):
+ with support.temp_dir() as dir:
+ fname = os.path.join(dir, 'db')
+ with dumbdbm.open(fname, 'n') as f:
+ self.assertEqual(list(f.keys()), [])
+ for key in self._dict:
+ f[key] = self._dict[key]
+ os.chmod(fname + ".dir", stat.S_IRUSR)
+ os.chmod(fname + ".dat", stat.S_IRUSR)
+ os.chmod(dir, stat.S_IRUSR|stat.S_IXUSR)
+ with dumbdbm.open(fname, 'r') as f:
+ self.assertEqual(sorted(f.keys()), sorted(self._dict))
+ f.close() # don't write
+
def tearDown(self):
_delete_files()
diff --git a/Misc/NEWS b/Misc/NEWS
index e52fbdb..d45f035 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -165,6 +165,9 @@
Library
-------
+- Issue #28847: dbm.dumb now supports reading read-only files and no longer
+ writes the index file when it is not changed.
+
- Issue #27030: Unknown escapes consisting of ``'\'`` and an ASCII letter in
re.sub() replacement templates regular expressions now are errors.