schema's test_alter_implicit_id_to_explicit warns/errors with "Field 'id' doesn't have a default value" on MySQL

[Tim Graham]

On MySQL 5.6.27:

django/db/backends/mysql/base.py:112: Warning: Field 'id' doesn't have a default value
  return self.cursor.execute(query, args)

On MySQL 5.7.10:

IntegrityError: (1364, "Field 'id' doesn't have a default value")

(I guess MySQL is getting stricter about data integrity.)

I'm not sure if it's something Django can fix or if the test should be skipped on MySQL.

[Tim Graham]

I think correcting the test should be sufficient: ​PR

[Tim Graham <timograham@…>]

In b49cc866:

Fixed #26116 -- Corrected schema's test_alter_implicit_id_to_explicit.

AUTOINCREMENT is dropped converting an AutoField to IntegerField
which isn't the point of this test. MySQL would warn or error about
this.

[Tim Graham <timograham@…>]

In 6919586b:

[1.8.x] Fixed #26116 -- Corrected schema's test_alter_implicit_id_to_explicit.

AUTOINCREMENT is dropped converting an AutoField to IntegerField
which isn't the point of this test. MySQL would warn or error about
this.

Backport of b49cc8664306f8b44e9e12ebb9e43791d508ec74 from master

[Tim Graham <timograham@…>]

In 1aee5e8:

[1.9.x] Fixed #26116 -- Corrected schema's test_alter_implicit_id_to_explicit.

AUTOINCREMENT is dropped converting an AutoField to IntegerField
which isn't the point of this test. MySQL would warn or error about
this.

Backport of b49cc8664306f8b44e9e12ebb9e43791d508ec74 from master