ManyToManyField does not respect the PositiveBigIntegerField in m2m intermediate table.

[Kfir Breger]

When creating a relation between 2 models using PositiveBigIntegerField on Postgresql, the relation table is created using regular ints as the column type. This in turn leads to out of bound error when using large numbers for ids.

from django.contrib.gis.db import models

class Node(models.Model):
    id = models.PositiveBigIntegerField(primary_key=True)
    point = models.PointField()

class Relation(models.Model):
   id = models.PositiveBigIntegerField(primary_key=True)
   nodes = models.ManyToManyField(Node)

The generated table will look like this:

   Column    |  Type   | Collation | Nullable |                    Default                     | Storage | Stats target | Description 
-------------+---------+-----------+----------+------------------------------------------------+---------+--------------+-------------
 id          | integer |           | not null | nextval('osm_relation_nodes_id_seq'::regclass) | plain   |              | 
 relation_id | integer |           | not null |                                                | plain   |              | 
 node_id     | integer |           | not null |                                                | plain   |              | 

As you can see, the PositiveBigInteger is not respected and a regular int is set

[Mariusz Felisiak]

Thanks for the report.

Note that everything works for BigIntegerField().

[Kfir Breger]

Thank you for the update. I'll switch to that for now.

[David Wobrock]

Hi!

I tried to tackle this issue, since it doesn't seem to complicated as a first glance :)
PR: ​https://github.com/django/django/pull/13592

[David Wobrock]

Add unit tests and improved the patch. Ready for another round of reviews :)

[Simon Charette]

Left some comments regarding the use of related_fields_match_type in tests.

[David Wobrock]

Thanks for the comment Simon! I adapted the tests, please see ​https://github.com/django/django/pull/13592#issuecomment-716212270 for more details

[Mariusz Felisiak <felisiak.mariusz@…>]

In 4ebd633:

Refs #32132 -- Added rel_db_type() tests for auto and integer fields.

[Mariusz Felisiak <felisiak.mariusz@…>]

In cfc7cd65:

Fixed #32132 -- Fixed column types in m2m intermediary tables for Positive(Big/Small)IntegerFields.