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Unable to read sqlite3 database keys in read-only directory with Python 3.13 with shelve #135386
Description
Bug report
Bug description:
In Python 3.13, sqlite is the new default for creating databases (https://www.python.org/downloads/release/python-3130/). However, it seems that it is not possible to get the keys of the database if the database file is in a read-only folder.
The setup:
mkdir PythonTest
cd PythonTest
python -c "import shelve; shelve.open('db.db', 'c')"
cd ..
chmod 555 PythonTest
Then running
import shelve
with shelve.open('PythonTest/db.db', 'r') as db:
print(list(db.keys()))will fail with
Traceback (most recent call last):
File "/usr/lib/python3.13/dbm/sqlite3.py", line 79, in _execute
return closing(self._cx.execute(*args, **kwargs))
~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
sqlite3.OperationalError: attempt to write a readonly database
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/read.py", line 5, in <module>
print(list(db.keys()))
~~~~^^^^^^^^^^^
File "<frozen _collections_abc>", line 854, in __len__
File "/usr/lib/python3.13/shelve.py", line 99, in __len__
return len(self.dict)
File "/usr/lib/python3.13/dbm/sqlite3.py", line 84, in __len__
with self._execute(GET_SIZE) as cu:
~~~~~~~~~~~~~^^^^^^^^^^
File "/usr/lib/python3.13/dbm/sqlite3.py", line 81, in _execute
raise error(str(exc))
dbm.sqlite3.error: attempt to write a readonly database
which I believe to be unexpected since the database was opened with the r flag, for read-only (see https://docs.python.org/3/library/dbm.html#dbm.open).
CPython versions tested on:
3.13.2 and 3.13.3
Operating systems tested on:
Linux (Ubuntu 24, Arch Linux)
Linked PRs
- gh-135386: Fix "unable to open database file" errors on readonly DB #135566
- [3.14] gh-135386: Fix "unable to open database file" errors on readonly DB (GH-135566) #138056
- [3.13] gh-135386: Fix "unable to open database file" errors on readonly DB (GH-135566) #138057
- gh-135386: Skip readonly tests for the root user #138058
- [3.13] gh-135386: Skip readonly tests for the root user (GH-138058) #138064
Activity
vstinner commentedon Jun 11, 2025
cc @erlend-aasland
GeneralK1ng commentedon Jun 16, 2025
Hi,
Thanks for reporting this issue! I have worked on a fix that adds the immutable=1 flag when opening a read-only SQLite DB to avoid WAL/SHM file errors.
I am preparing a PR #135566 and will submit it soon for review.
Looking forward to feedback from the maintainers and community.
Thanks!
pythongh-135386: Fix dbm.sqlite3 readonly open error by using immutab…
pythongh-135386: Fix dbm.sqlite3 readonly open error by using immutab…
pythongh-135386: Fix dbm.sqlite3 readonly open error by using immutab…
gh-135386: Fix "unable to open database file" errors on readonly DB (G…
pythongh-135386: Fix "unable to open database file" errors on readonl…
pythongh-135386: Fix "unable to open database file" errors on readonl…
[3.13] gh-135386: Fix "unable to open database file" errors on readon…
pythongh-135386: Skip readonly tests for the root user
pythongh-135386: Fix "unable to open database file" errors on readonl…
gh-135386: Skip readonly tests for the root user (GH-138058)
pythongh-135386: Skip readonly tests for the root user (pythonGH-138058)
[3.13] gh-135386: Skip readonly tests for the root user (GH-138058) (G…
[3.14] gh-135386: Fix "unable to open database file" errors on readon…
spiral-fitting: date CPython's immutable=1 to 3.13.8 and 3.14.1