René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Surprising choices_provider behavior in 4.0 when using sqlite3","articleBody":"People upgrading single-threaded applications to 4.0 may be surprised. Reproduce with the following methodology (tested with Python3.14.5 on OSX):\n\n1. Start the shell.\n2. Type _t_ and then _TAB_ _TAB_ and a SQLite error occurs.\n\n\u003e Failed query: SQLite objects created in a thread can only be used in that same thread. The object was created in thread id 8421351040 and this is thread id 6186856448.\n\nMWE:\n\n```Python\n#!/usr/bin/env python3\n\"\"\"A simple cmd2 application.\"\"\"\nfrom cmd2 import Cmd, Cmd2ArgumentParser, with_argparser, Choices\nimport sqlite3\n\nclass FirstApp(Cmd):\n    # possibly unwise workaround\n    # conn = sqlite3.connect(':memory:', check_same_thread=False)\n    conn = sqlite3.connect(':memory:')\n    conn.executescript('''\n        CREATE TABLE xxx (X INTEGER);\n        INSERT INTO  xxx (X) values(3);\n        INSERT INTO  xxx (X) values(4);\n        INSERT INTO  xxx (X) values(5);\n        INSERT INTO  xxx (X) values(6);\n    ''')\n\n    \"\"\"A simple cmd2 application.\"\"\"\n    def do_hello_world(self, _: cmd2.Statement):\n        self.poutput(f'Hello World: {self.conn}')\n\n    def _t_completer(self):\n        try:\n            ids = list(map(lambda x: x[0], self.conn.execute('SELECT X FROM xxx').fetchall()))\n            return Choices.from_values(ids)\n        except sqlite3.Error as exc:\n            self.perror(f'Failed query: {exc}')\n\n    set_t_parser = Cmd2ArgumentParser(description='Test')\n    set_t_parser.add_argument('ttt', help='ttt help', choices_provider=_t_completer)\n    @with_argparser(set_t_parser)\n    def do_t(self, args):\n        self.poutput(args.ttt)\n\nif __name__ == '__main__':\n    import sys\n    \n    c = FirstApp()\n    sys.exit(c.cmdloop())\n```\n\n","author":{"url":"https://github.com/bknotwell","@type":"Person","name":"bknotwell"},"datePublished":"2026-06-07T18:39:32.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":10},"url":"https://github.com/1680/cmd2/issues/1680"}