bpo-33106: change dbm key deletion error for readonly file from KeyError to dbm.error (#6295)
diff --git a/Doc/library/dbm.rst b/Doc/library/dbm.rst
index ab45cac..57ae547 100644
--- a/Doc/library/dbm.rst
+++ b/Doc/library/dbm.rst
@@ -73,6 +73,10 @@
.. versionchanged:: 3.2
:meth:`get` and :meth:`setdefault` are now available in all database modules.
+.. versionchanged:: 3.8
+ Deleting a key from a read-only database raises database module specific error
+ instead of :exc:`KeyError`.
+
Key and values are always stored as bytes. This means that when
strings are used they are implicitly converted to the default encoding before
being stored.
diff --git a/Doc/whatsnew/3.8.rst b/Doc/whatsnew/3.8.rst
index 0d0d1ca..b38a1a7 100644
--- a/Doc/whatsnew/3.8.rst
+++ b/Doc/whatsnew/3.8.rst
@@ -483,6 +483,12 @@
external entities by default.
(Contributed by Christian Heimes in :issue:`17239`.)
+* Deleting a key from a read-only :mod:`dbm` database (:mod:`dbm.dumb`,
+ :mod:`dbm.gnu` or :mod:`dbm.ndbm`) raises :attr:`error` (:exc:`dbm.dumb.error`,
+ :exc:`dbm.gnu.error` or :exc:`dbm.ndbm.error`) instead of :exc:`KeyError`.
+ (Contributed by Xiang Zhang in :issue:`33106`.)
+
+
CPython bytecode changes
------------------------
diff --git a/Lib/dbm/dumb.py b/Lib/dbm/dumb.py
index e5c17f5..6cef72a 100644
--- a/Lib/dbm/dumb.py
+++ b/Lib/dbm/dumb.py
@@ -185,7 +185,7 @@
def __setitem__(self, key, val):
if self._readonly:
- raise ValueError('The database is opened for reading only')
+ raise error('The database is opened for reading only')
if isinstance(key, str):
key = key.encode('utf-8')
elif not isinstance(key, (bytes, bytearray)):
@@ -222,7 +222,7 @@
def __delitem__(self, key):
if self._readonly:
- raise ValueError('The database is opened for reading only')
+ raise error('The database is opened for reading only')
if isinstance(key, str):
key = key.encode('utf-8')
self._verify_open()
diff --git a/Lib/test/test_dbm_dumb.py b/Lib/test/test_dbm_dumb.py
index 58b9d17..e8e827e 100644
--- a/Lib/test/test_dbm_dumb.py
+++ b/Lib/test/test_dbm_dumb.py
@@ -82,10 +82,10 @@
self.init_db()
f = dumbdbm.open(_fname, 'r')
self.read_helper(f)
- with self.assertRaisesRegex(ValueError,
+ with self.assertRaisesRegex(dumbdbm.error,
'The database is opened for reading only'):
f[b'g'] = b'x'
- with self.assertRaisesRegex(ValueError,
+ with self.assertRaisesRegex(dumbdbm.error,
'The database is opened for reading only'):
del f[b'a']
# get() works as in the dict interface
diff --git a/Lib/test/test_dbm_gnu.py b/Lib/test/test_dbm_gnu.py
index 16b7fe6..f1c7d34 100644
--- a/Lib/test/test_dbm_gnu.py
+++ b/Lib/test/test_dbm_gnu.py
@@ -131,6 +131,17 @@
self.assertEqual(db['Unicode key \U0001f40d'],
'Unicode value \U0001f40d'.encode())
+ def test_write_readonly_file(self):
+ with gdbm.open(filename, 'c') as db:
+ db[b'bytes key'] = b'bytes value'
+ with gdbm.open(filename, 'r') as db:
+ with self.assertRaises(gdbm.error):
+ del db[b'not exist key']
+ with self.assertRaises(gdbm.error):
+ del db[b'bytes key']
+ with self.assertRaises(gdbm.error):
+ db[b'not exist key'] = b'not exist value'
+
@unittest.skipUnless(TESTFN_NONASCII,
'requires OS support of non-ASCII encodings')
def test_nonascii_filename(self):
diff --git a/Lib/test/test_dbm_ndbm.py b/Lib/test/test_dbm_ndbm.py
index bd411da..7ac75c5 100644
--- a/Lib/test/test_dbm_ndbm.py
+++ b/Lib/test/test_dbm_ndbm.py
@@ -90,6 +90,17 @@
self.assertEqual(db['Unicode key \U0001f40d'],
'Unicode value \U0001f40d'.encode())
+ def test_write_readonly_file(self):
+ with dbm.ndbm.open(self.filename, 'c') as db:
+ db[b'bytes key'] = b'bytes value'
+ with dbm.ndbm.open(self.filename, 'r') as db:
+ with self.assertRaises(error):
+ del db[b'not exist key']
+ with self.assertRaises(error):
+ del db[b'bytes key']
+ with self.assertRaises(error):
+ db[b'not exist key'] = b'not exist value'
+
@unittest.skipUnless(support.TESTFN_NONASCII,
'requires OS support of non-ASCII encodings')
def test_nonascii_filename(self):
diff --git a/Misc/NEWS.d/next/Library/2018-03-30-01-20-35.bpo-33106.zncfvW.rst b/Misc/NEWS.d/next/Library/2018-03-30-01-20-35.bpo-33106.zncfvW.rst
new file mode 100644
index 0000000..859c09c
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-03-30-01-20-35.bpo-33106.zncfvW.rst
@@ -0,0 +1,2 @@
+Deleting a key from a read-only dbm database raises module specfic error
+instead of KeyError.
diff --git a/Modules/_dbmmodule.c b/Modules/_dbmmodule.c
index 081184a..21784ae 100644
--- a/Modules/_dbmmodule.c
+++ b/Modules/_dbmmodule.c
@@ -36,6 +36,7 @@
typedef struct {
PyObject_HEAD
+ int flags;
int di_size; /* -1 means recompute */
DBM *di_dbm;
} dbmobject;
@@ -60,6 +61,7 @@
if (dp == NULL)
return NULL;
dp->di_size = -1;
+ dp->flags = flags;
/* See issue #19296 */
if ( (dp->di_dbm = dbm_open((char *)file, flags, mode)) == 0 ) {
PyErr_SetFromErrnoWithFilename(DbmError, file);
@@ -143,13 +145,20 @@
if (w == NULL) {
if ( dbm_delete(dp->di_dbm, krec) < 0 ) {
dbm_clearerr(dp->di_dbm);
- PyErr_SetObject(PyExc_KeyError, v);
+ /* we might get a failure for reasons like file corrupted,
+ but we are not able to distinguish it */
+ if (dp->flags & O_RDWR) {
+ PyErr_SetObject(PyExc_KeyError, v);
+ }
+ else {
+ PyErr_SetString(DbmError, "cannot delete item from database");
+ }
return -1;
}
} else {
if ( !PyArg_Parse(w, "s#", &drec.dptr, &tmp_size) ) {
PyErr_SetString(PyExc_TypeError,
- "dbm mappings have byte or string elements only");
+ "dbm mappings have bytes or string elements only");
return -1;
}
drec.dsize = tmp_size;
@@ -335,7 +344,7 @@
else {
if ( !PyArg_Parse(default_value, "s#", &val.dptr, &tmp_size) ) {
PyErr_SetString(PyExc_TypeError,
- "dbm mappings have byte string elements only");
+ "dbm mappings have bytes or string elements only");
return NULL;
}
val.dsize = tmp_size;
diff --git a/Modules/_gdbmmodule.c b/Modules/_gdbmmodule.c
index 46bb59a..cc94e60 100644
--- a/Modules/_gdbmmodule.c
+++ b/Modules/_gdbmmodule.c
@@ -186,14 +186,19 @@
dp->di_size = -1;
if (w == NULL) {
if (gdbm_delete(dp->di_dbm, krec) < 0) {
- PyErr_SetObject(PyExc_KeyError, v);
+ if (gdbm_errno == GDBM_ITEM_NOT_FOUND) {
+ PyErr_SetObject(PyExc_KeyError, v);
+ }
+ else {
+ PyErr_SetString(DbmError, gdbm_strerror(gdbm_errno));
+ }
return -1;
}
}
else {
if (!PyArg_Parse(w, "s#", &drec.dptr, &drec.dsize)) {
PyErr_SetString(PyExc_TypeError,
- "gdbm mappings have byte or string elements only");
+ "gdbm mappings have bytes or string elements only");
return -1;
}
errno = 0;