inspectdb on SQLite crashes when introspecting varchar primary key with TypeError: unhashable type: 'dict'

[Can Sarıgöl]

I created a project with version 2.2a1 and run migrate after then run inspectdb. I got this error

class DjangoSession(models.Model):
Traceback (most recent call last):
  File "./manage.py", line 21, in <module>
    main()
  File "./manage.py", line 17, in main
    execute_from_command_line(sys.argv)
  File "/Users/can/Documents/Contribute_projects/Tests/django2_2_alfa2/venv/lib/python3.7/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/Users/can/Documents/Contribute_projects/Tests/django2_2_alfa2/venv/lib/python3.7/site-packages/django/core/management/__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/can/Documents/Contribute_projects/Tests/django2_2_alfa2/venv/lib/python3.7/site-packages/django/core/management/base.py", line 323, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Users/can/Documents/Contribute_projects/Tests/django2_2_alfa2/venv/lib/python3.7/site-packages/django/core/management/base.py", line 364, in execute
    output = self.handle(*args, **options)
  File "/Users/can/Documents/Contribute_projects/Tests/django2_2_alfa2/venv/lib/python3.7/site-packages/django/core/management/commands/inspectdb.py", line 34, in handle
    for line in self.handle_inspection(options):
  File "/Users/can/Documents/Contribute_projects/Tests/django2_2_alfa2/venv/lib/python3.7/site-packages/django/core/management/commands/inspectdb.py", line 131, in handle_inspection
    field_type, field_params, field_notes = self.get_field_type(connection, table_name, row)
  File "/Users/can/Documents/Contribute_projects/Tests/django2_2_alfa2/venv/lib/python3.7/site-packages/django/core/management/commands/inspectdb.py", line 239, in get_field_type
    field_type = connection.introspection.get_field_type(row.type_code, row)
  File "/Users/can/Documents/Contribute_projects/Tests/django2_2_alfa2/venv/lib/python3.7/site-packages/django/db/backends/sqlite3/introspection.py", line 65, in get_field_type
    if description.pk and field_type in {'BigIntegerField', 'IntegerField'}:
TypeError: unhashable type: 'dict'

[Carlton Gibson]

OK, yes, thanks for the report.

This works against 2.1.5 but errors as reported against 2.2a1:

django-admin startproject ticket_30115
cd ticket_30115/
./manage.py migrate
./manage.py inspectdb

[Can Sarıgöl]

​PR

[Tim Graham]

Is that code untested or this caused by a version of SQLite that's untested on Jenkins?

[Can Sarıgöl]

I am adding test for it

[Carlton Gibson]

>>> import sqlite3
>>> sqlite3.sqlite_version
'3.24.0'

[Nick Pope]

Sorry about this. I clearly forgot to take the special case of a tuple of (field_type, field_params_dict) into account, field_params_dict being the source of the error.

It turns out that this special case was a hack to handle max_length for CharField on SQLite only which was introduced by 9ede371c85a97406eecb19974ab01163839636a0.

Since a9a773ff38a9fd28085e8b62b8a160c4e2ea5efb, size is returned by get_table_description() on SQLite so row.internal_size is always overriding the max_length returned in field_params_dict.

Here is a ​PR that fixes the issue by removing this legacy approach to handling max_length.

[Nick Pope]

I think no tests should be needed as we're removing the code that caused the broken behaviour.

[Tim Graham <timograham@…>]

In bff748df:

Fixed #30115 -- Fixed SQLite introspection crash with a varchar primary key.

Removed obsolete max_length handling for CharField that caused the issue.
Regression in a35d2a4510d5beec398b1007aaa26492d6aedf97.

[Tim Graham <timograham@…>]

In e53e642:

[2.2.x] Fixed #30115 -- Fixed SQLite introspection crash with a varchar primary key.

Removed obsolete max_length handling for CharField that caused the issue.
Regression in a35d2a4510d5beec398b1007aaa26492d6aedf97.

Backport of bff748df3e1e1c0077e02df2b77bda2b827ad129 from master.