[Django] #22445: Doc on reversible data migrations needed
Django
-------------------------------------------+----------------------------
Reporter: kmtracey | Owner: nobody
Type: Bug | Status: new
Component: Documentation | Version: 1.7-beta-1
Severity: Release blocker | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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If I create a data migration, run it, then try to migrate back to before
it, I get:
{{{
Unapplying m3app.0003_auto_20140415_1022...Traceback (most recent call
last):
File "./manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/home/kmtracey/.virtualenvs/uncfm/lib/python3.3/site-
packages/django/core/management/__init__.py", line 427, in
execute_from_command_line
utility.execute()
File "/home/kmtracey/.virtualenvs/uncfm/lib/python3.3/site-
packages/django/core/management/__init__.py", line 419, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/kmtracey/.virtualenvs/uncfm/lib/python3.3/site-
packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/home/kmtracey/.virtualenvs/uncfm/lib/python3.3/site-
packages/django/core/management/base.py", line 337, in execute
output = self.handle(*args, **options)
File "/home/kmtracey/.virtualenvs/uncfm/lib/python3.3/site-
packages/django/core/management/commands/migrate.py", line 145, in handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "/home/kmtracey/.virtualenvs/uncfm/lib/python3.3/site-
packages/django/db/migrations/executor.py", line 62, in migrate
self.unapply_migration(migration, fake=fake)
File "/home/kmtracey/.virtualenvs/uncfm/lib/python3.3/site-
packages/django/db/migrations/executor.py", line 114, in unapply_migration
migration.unapply(project_state, schema_editor)
File "/home/kmtracey/.virtualenvs/uncfm/lib/python3.3/site-
packages/django/db/migrations/migration.py", line 121, in unapply
raise Migration.IrreversibleError("Operation %s in %s is not
reversible" % (operation, self))
django.db.migrations.migration.IrreversibleError: Operation <RunPython
<function load_initial_data at 0x7f7af2424050>> in
m3app.0003_auto_20140415_1022 is not reversible
}}}
I cannot find any documentation on how to create a reversible data
migration. I'm used to doing this with South, I assume there is some way
to do this in the new migrations framework? We need some doc on how to do
it...or if this is not just a missing doc issue then this needs to be re-
classified as a migrations code issue...
--
Ticket URL: <https://code.djangoproject.com/ticket/22445>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
Django
Reporter: kmtracey | Owner: nobody
Type: Bug | Status: new
Component: Documentation | Version: 1.7-beta-1
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by kmtracey):
Peeking at the code reveals !RunPython can be handed a 2nd callable to do
the "reverse" operation. So I think this doc:
https://docs.djangoproject.com/en/1.7/topics/migrations/#data-migrations
specifically needs to be updated to include mention of that, at a minimum.
--
Ticket URL: <https://code.djangoproject.com/ticket/22445#comment:1>
Django
Reporter: kmtracey | Owner: nobody
Type: Bug | Status: new
Component: Documentation | Version: 1.7-beta-1
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 charettes):
* stage: Unreviewed => Accepted
--
Ticket URL: <https://code.djangoproject.com/ticket/22445#comment:2>
Django
Reporter: kmtracey | Owner: timo
Type: Bug | Status: assigned
Component: Documentation | Version: 1.7-beta-1
Severity: Release blocker | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by timo):
* status: new => assigned
* owner: nobody => timo
--
Ticket URL: <https://code.djangoproject.com/ticket/22445#comment:3>
Django
Reporter: kmtracey | Owner: timo
Type: Bug | Status: assigned
Severity: Release blocker | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by timo):
It's covered in the [https://docs.djangoproject.com/en/1.7/ref/migration-
operations/#runpython RunPython reference], but I will add a couple
sentences to the topic guide.
--
Ticket URL: <https://code.djangoproject.com/ticket/22445#comment:4>
Django
Reporter: kmtracey | Owner: timo
Component: Documentation | Version: 1.7-beta-1
Severity: Release blocker | Resolution: fixed
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 <timograham@…>):
* status: assigned => closed
* resolution: => fixed
Comment:
In [changeset:"1ce759b69f641fd780790630c79559fc68a2d923"]:
{{{
#!CommitTicketReference repository=""
revision="1ce759b69f641fd780790630c79559fc68a2d923"
Fixed #22445 -- Added how to perform a reverse data migration to topic
guide.
Thanks Karen Tracey for the report.
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/22445#comment:5>
Django
Reporter: kmtracey | Owner: timo
Type: Bug | Status: closed
Severity: Release blocker | Resolution: fixed
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by Tim Graham <timograham@…>):
In [changeset:"23f3c53aff54b7f298f29e97042d00dbd9379d00"]:
{{{
#!CommitTicketReference repository=""
revision="23f3c53aff54b7f298f29e97042d00dbd9379d00"
[1.7.x] Fixed #22445 -- Added how to perform a reverse data migration to
topic guide.
Thanks Karen Tracey for the report.
Backport of 1ce759b69f from master
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/22445#comment:6>