New submission from Lumír Balhar <frenzy.madn...@gmail.com>: Hello.
I've discovered this issue when I was debugging a test failure in IPython. See this issue for more details (not needed): https://github.com/ipython/ipython/issues/12906 I'm testing this on Fedora Linux with Python 3.10.0a7 from our RPM package with SQLite 3.35.4. I have a very simple SQLite database: # sqlite3 test.sqlite SQLite version 3.35.4 2021-04-02 15:20:15 Enter ".help" for usage hints. sqlite> .dump PRAGMA foreign_keys=OFF; BEGIN TRANSACTION; CREATE TABLE sessions (session integer primary key autoincrement, start timestamp, end timestamp, num_cmds integer, remark text); INSERT INTO sessions VALUES(1,'2021-04-13 09:44:58.903345',NULL,NULL,''); DELETE FROM sqlite_sequence; INSERT INTO sqlite_sequence VALUES('sessions',1); COMMIT; When I query it without special converters, it works well: # python3 >>> import sqlite3 >>> conn = sqlite3.connect('test.sqlite') >>> c = conn.cursor() >>> c.execute("SELECT * from sessions where session == 1").fetchone() (1, '2021-04-13 09:44:58.903345', None, None, '') >>> but with detect_types=sqlite3.PARSE_DECLTYPES, it fails to parse the date and time: # python3 >>> import sqlite3 >>> conn = sqlite3.connect('test.sqlite', detect_types=sqlite3.PARSE_DECLTYPES) >>> c = conn.cursor() >>> c.execute("SELECT * from sessions where session == 1").fetchone() Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/usr/lib64/python3.10/sqlite3/dbapi2.py", line 67, in convert_timestamp datepart, timepart = val.split(b" ") ValueError: not enough values to unpack (expected 2, got 1) >>> With help of pdb in ipython, I've discovered that the value convert_timestamp gets to parse is an empty bytestring: In [5]: c.execute("SELECT * from sessions where session == 1").fetchone() --------------------------------------------------------------------------- ValueError Traceback (most recent call last) <ipython-input-5-c234e57285e4> in <module> ----> 1 c.execute("SELECT * from sessions where session == 1").fetchone() /usr/lib64/python3.10/sqlite3/dbapi2.py in convert_timestamp(val) 65 66 def convert_timestamp(val): ---> 67 datepart, timepart = val.split(b" ") 68 year, month, day = map(int, datepart.split(b"-")) 69 timepart_full = timepart.split(b".") ValueError: not enough values to unpack (expected 2, got 1) > /usr/lib64/python3.10/sqlite3/dbapi2.py(67)convert_timestamp() 65 66 def convert_timestamp(val): ---> 67 datepart, timepart = val.split(b" ") 68 year, month, day = map(int, datepart.split(b"-")) 69 timepart_full = timepart.split(b".") ipdb> val b'' ipdb> Is anything in my database wrong? It seems that the content of the start column is correct and covert_timestamp should be able to parse it. Is it possible that the troublemaker here is the empty column `end` of type timestamp? Answer to my own question: yes, the issue here is that the column `end` is of type timestamp and it's empty. If I update it with a date and time, everything works: # sqlite3 test.sqlite sqlite> update sessions set end='2021-04-14 09:44:58.903345' where session = 1; sqlite> select * from sessions; 1|2021-04-13 09:44:58.903345|2021-04-14 09:44:58.903345|| sqlite> # python3 >>> import sqlite3 >>> conn = sqlite3.connect('test.sqlite', detect_types=sqlite3.PARSE_DECLTYPES) >>> c = conn.cursor() >>> c.execute("SELECT * from sessions where session == 1").fetchone() (1, datetime.datetime(2021, 4, 13, 9, 44, 58, 903345), datetime.datetime(2021, 4, 14, 9, 44, 58, 903345), None, '') So, the final question is whether this is correct behavior. I believe that columns without content should not be passed to converters. ---------- components: Library (Lib) messages: 390953 nosy: frenzy priority: normal severity: normal status: open title: sqlite: convert_timestamp raises ValueError for empty columns versions: Python 3.10 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue43831> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
