[Django] #28816: Silent data loss when decreasing the max_length of a CharField
Django
-------------------------------------+-------------------------------------
Reporter: Gavin | Owner: nobody
Wahl |
Type: Bug | Status: new
Component: Database | Version: 1.11
layer (models, ORM) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
I have a CharField that I want to decrease the max_length on. I change the
value and generate a migration, then run it on my database.
Desired:
I should get an error from postgres if existing data doesn't fit in the
new length:
ERROR: value too long for type character varying(5)
Observed:
Any existing data longer than the new_max length is truncated and lost.
This behavior was introducted in #25002, which unconditionally added a
cast to the new type. This changes the default behavior of postgres (which
is to never lose data), to implicitly truncate. Django should not lose
data by default.
--
Ticket URL: <https://code.djangoproject.com/ticket/28816>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
Django
Reporter: Gavin Wahl | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.11
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Tim Graham):
* component: Database layer (models, ORM) => Migrations
* stage: Unreviewed => Accepted
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:1>
Django
Reporter: Gavin Wahl | Owner: ChillarAnand
Type: Bug | Status: assigned
Component: Migrations | Version: 1.11
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by ChillarAnand):
* owner: nobody => ChillarAnand
* status: new => assigned
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:2>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Type: Bug | Status: assigned
Component: Migrations | Version: 1.11
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 0 | UI/UX: 0
Changes (by Hasan Ramezani):
* owner: ChillarAnand => Hasan Ramezani
* needs_better_patch: 0 => 1
* has_patch: 0 => 1
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:3>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Type: Bug | Status: assigned
Component: Migrations | Version: 1.11
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Hasan Ramezani):
* needs_better_patch: 1 => 0
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:4>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Type: Bug | Status: assigned
Severity: Normal | Resolution:
Keywords: | Triage Stage: Ready for checkin
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by felixxm):
* status: new => assigned
* version: 1.11 => master
* stage: Accepted => Ready for checkin
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:5>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Component: Migrations | Version: master
Severity: Normal | Resolution: fixed
Keywords: | Triage Stage: Ready for checkin
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Mariusz Felisiak <felisiak.mariusz@…>):
* status: assigned => closed
* resolution: => fixed
Comment:
In [changeset:"1378d665a1c85897d951f2ca9618b848fdbba2e7" 1378d665]:
{{{
#!CommitTicketReference repository=""
revision="1378d665a1c85897d951f2ca9618b848fdbba2e7"
Fixed #28816 -- Prevented silencing data loss when decreasing
CharField.max_length on PostgreSQL.
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:6>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Type: Bug | Status: closed
Component: Migrations | Version: master
Severity: Normal | Resolution: fixed
Keywords: | Triage Stage: Ready for checkin
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by felixxm):
This solution doesn't prevent silencing data loss when decreasing
`CharField.max_length` for a base field of `ArrayField` (see
[https://github.com/django/django/pull/11817#discussion_r328013173
comment]).
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:7>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Type: Bug | Status: closed
Component: Migrations | Version: master
Severity: Normal | Resolution: fixed
Keywords: | Triage Stage: Ready for checkin
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by Simon Charette):
Or decreasing the `size` of an `ArrayField`.
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:8>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Type: Bug | Status: closed
Component: Migrations | Version: master
Severity: Normal | Resolution: fixed
Keywords: | Triage Stage: Ready for checkin
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by Hasan Ramezani):
Replying to [comment:7 felixxm]:
> This solution doesn't prevent silencing data loss when decreasing
`CharField.max_length` for a base field of `ArrayField` (see
[https://github.com/django/django/pull/11817#discussion_r328013173
comment]).
[https://github.com/django/django/pull/11847 PR]
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:9>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Component: Migrations | Version: master
Severity: Normal | Resolution:
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Hasan Ramezani):
* status: closed => new
* resolution: fixed =>
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:10>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Component: Migrations | Version: master
Severity: Normal | Resolution:
Keywords: | Triage Stage: Ready for checkin
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by Hasan Ramezani):
Reopen the ticket because of @felixxm
[https://code.djangoproject.com/ticket/28816#comment:7 comment].
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:11>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Component: Migrations | Version: master
Severity: Normal | Resolution:
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by felixxm):
* stage: Ready for checkin => Accepted
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:12>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Component: Migrations | Version: master
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 0 | UI/UX: 0
Changes (by felixxm):
* needs_better_patch: 0 => 1
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:13>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Component: Migrations | Version: master
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Hasan Ramezani):
* needs_better_patch: 1 => 0
Comment:
The patch was changed based on @felixxm
[https://github.com/django/django/pull/11847#discussion_r334936154 comment
on the PR].
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:14>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Component: Migrations | Version: master
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by Mariusz Felisiak <felisiak.mariusz@…>):
In [changeset:"ef4beafa2ce58a81a56ffd48a20a6153126b611a" ef4beafa]:
{{{
#!CommitTicketReference repository=""
revision="ef4beafa2ce58a81a56ffd48a20a6153126b611a"
Refs #28816 -- Prevented silencing data loss when decreasing
CharField.max_length for ArrayField.base_field on PostgreSQL.
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:15>
Django
Reporter: Gavin Wahl | Owner: Hasan Ramezani
Component: Migrations | Version: master
Severity: Normal | Resolution: fixed
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by felixxm):
* status: new => closed
* resolution: => fixed
--
Ticket URL: <https://code.djangoproject.com/ticket/28816#comment:16>