[Django] #22997: Migration fails when removing explicit primary key (Postgres)

[Django]

#22997: Migration fails when removing explicit primary key (Postgres)
----------------------------------------------+----------------------------
Reporter: a.lloyd.flanagan@… | Owner: nobody
Type: Uncategorized | Status: new
Component: Database layer (models, ORM) | Version: 1.7-rc-1
Severity: Normal | Keywords: migrate
Triage Stage: Unreviewed | primary_key
Easy pickings: 0 | Has patch: 0
| UI/UX: 0
----------------------------------------------+----------------------------
The automatic migration created by migrate fails when

* a table was created with a field where "primary_key=True" is specified.
* data is added to the table
* The model is modified so that no field is primary key, and Django auto-
creates "id" field.

To reproduce the problem:

1. create new model, set some field as primary key
2. set up migrations with initial migration
3. modify model so field is not primary key
4. generate migration

Problems:

* will ask for default value for auto-generated ID field
* will try to create id field as primary key, before modifying existing
key

Manual Fix:

* remove default from models.AutoField() call
* reverse order of operations so AlterField() comes before AddField()

I'm attaching a session log with a complete transcript.

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Ticket URL: <https://code.djangoproject.com/ticket/22997>
Django <https://code.djangoproject.com/>
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[Django]

#22997: Migration fails when removing explicit primary key (Postgres)

-------------------------------------+------------------------------------
Reporter: a.lloyd.flanagan@… | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7-rc-1
Severity: Normal | Resolution:
Keywords: migrate primary_key | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+------------------------------------
Changes (by timo):

* needs_better_patch: => 0
* component: Database layer (models, ORM) => Migrations
* needs_tests: => 0
* needs_docs: => 0
* type: Uncategorized => Bug
* stage: Unreviewed => Accepted

Comment:

I guess it's probably too much of an edge case to be a blocker for 1.7,
but would be nice if it "just worked".

--
Ticket URL: <https://code.djangoproject.com/ticket/22997#comment:1>

[Django]

#22997: Migration fails when removing explicit primary key (Postgres)

-------------------------------------+------------------------------------
Reporter: a.lloyd.flanagan@… | Owner: nobody

Type: Bug | Status: new
Component: Migrations | Version: 1.7

Severity: Normal | Resolution:
Keywords: migrate primary_key | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+------------------------------------

Changes (by timgraham):

* version: 1.7-rc-1 => 1.7

--
Ticket URL: <https://code.djangoproject.com/ticket/22997#comment:2>

[Django]

#22997: Migration fails when removing explicit primary key (Postgres)

-------------------------------------+------------------------------------
Reporter: a.lloyd.flanagan@… | Owner: nobody

Type: Bug | Status: new
Component: Migrations | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrate primary_key | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+------------------------------------

Comment (by timgraham):

#24030 seems related.

--
Ticket URL: <https://code.djangoproject.com/ticket/22997#comment:3>

[Django]

#22997: Migration fails when removing explicit primary key (Postgres)

-------------------------------------+------------------------------------
Reporter: a.lloyd.flanagan@… | Owner: bcail
Type: Bug | Status: assigned

Component: Migrations | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrate primary_key | Triage Stage: Accepted

Has patch: 1 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+------------------------------------

Changes (by bcail):

* cc: bcail (added)
* has_patch: 0 => 1
* owner: nobody => bcail
* status: new => assigned

Comment:

I opened [https://github.com/django/django/pull/17923 a PR] for one of the
problems - where a default is added to an AutoField.
--
Ticket URL: <https://code.djangoproject.com/ticket/22997#comment:4>

[Django]

#22997: Migration fails when removing explicit primary key (Postgres)

-------------------------------------+------------------------------------
Reporter: a.lloyd.flanagan@… | Owner: bcail
Type: Bug | Status: assigned
Component: Migrations | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrate primary_key | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+------------------------------------

Comment (by bcail):

I updated the PR to handle the other issue as well - to generate altered
fields before added fields.
--
Ticket URL: <https://code.djangoproject.com/ticket/22997#comment:5>

[Django]

#22997: Migration fails when removing explicit primary key (Postgres)

-------------------------------------+------------------------------------
Reporter: a.lloyd.flanagan@… | Owner: bcail
Type: Bug | Status: assigned
Component: Migrations | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrate primary_key | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 1

Easy pickings: 0 | UI/UX: 0
-------------------------------------+------------------------------------

Changes (by Bhuvnesh):

* needs_better_patch: 0 => 1

--
Ticket URL: <https://code.djangoproject.com/ticket/22997#comment:6>

[Django]

#22997: Migration fails when removing explicit primary key (Postgres)

-------------------------------------+------------------------------------
Reporter: a.lloyd.flanagan@… | Owner: bcail
Type: Bug | Status: assigned
Component: Migrations | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrate primary_key | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 0

Easy pickings: 0 | UI/UX: 0
-------------------------------------+------------------------------------

Changes (by bcail):

* needs_better_patch: 1 => 0

--
Ticket URL: <https://code.djangoproject.com/ticket/22997#comment:7>

[Django]

#22997: Migration fails when removing explicit primary key

-------------------------------------+------------------------------------
Reporter: a.lloyd.flanagan@… | Owner: bcail
Type: Bug | Status: assigned
Component: Migrations | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrate primary_key | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+------------------------------------

Changes (by Sarah Boyce):

* summary: Migration fails when removing explicit primary key (Postgres)
=> Migration fails when removing explicit primary key

Comment:

(I can replicate also on SQLite so removing Postgres reference as it does
not only relate to Postgres)
--
Ticket URL: <https://code.djangoproject.com/ticket/22997#comment:8>

[Django]

#22997: Migration fails when removing explicit primary key (Postgres)

-------------------------------------+------------------------------------
Reporter: a.lloyd.flanagan@… | Owner: bcail
Type: Bug | Status: assigned
Component: Migrations | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrate primary_key | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+------------------------------------
Changes (by Sarah Boyce):

* summary: Migration fails when removing explicit primary key => Migration

fails when removing explicit primary key (Postgres)

Comment:

(Ah perhaps the fix as described is only related to Postgres? Can confirm
the same migrations and prompting happen on other databases).
--
Ticket URL: <https://code.djangoproject.com/ticket/22997#comment:9>

[Django]

#22997: Migration fails when removing explicit primary key

-------------------------------------+------------------------------------
Reporter: a.lloyd.flanagan@… | Owner: bcail
Type: Bug | Status: assigned
Component: Migrations | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrate primary_key | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 1

Easy pickings: 0 | UI/UX: 0
-------------------------------------+------------------------------------
Changes (by Sarah Boyce):

* needs_better_patch: 0 => 1
* summary: Migration fails when removing explicit primary key (Postgres)
=> Migration fails when removing explicit primary key

Comment:

#35416 is a duplicate.
Marking "Patch needs improvement" as the case, as described in #35416,
needs to be handled.
--
Ticket URL: <https://code.djangoproject.com/ticket/22997#comment:10>