#28073: RemoveField.state_forwards() crashes with AttributeError: 'NoneType' object has no attribute 'is_relation' ---------------------------------+------------------------------------ Reporter: Logan Gunthorpe | 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 Python Force):
* status: closed => new * resolution: needsinfo => Old description: > Hi, > > I'm trying to upgrade my project (originally created on 1.7) to the > latest release but there's an issue with my existing migration files not > working. The backtrace is below. > > I'll attache my migration files but it seems to be related to the > migration removing the 'id' field which was automatically created and > then removed in a future migration. Commenting out the RemoveField in the > second migration seems to fix the issue but I'm not sure if it's entirely > correct to do so. > > Thanks, > > Logan > > > {{{ > Traceback (most recent call last): > File "./manage.py", line 10, in <module> > execute_from_command_line(sys.argv) > File > "/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site- > packages/django/core/management/__init__.py", line 363, in > execute_from_command_line > utility.execute() > File > "/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site- > packages/django/core/management/__init__.py", line 355, in execute > self.fetch_command(subcommand).run_from_argv(self.argv) > File > "/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site- > packages/django/core/management/base.py", line 283, in run_from_argv > self.execute(*args, **cmd_options) > File > "/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site- > packages/django/core/management/base.py", line 330, in execute > output = self.handle(*args, **options) > File > "/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site- > packages/django/core/management/commands/migrate.py", line 163, in handle > pre_migrate_state = > executor._create_project_state(with_applied_migrations=True) > File > "/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site- > packages/django/db/migrations/executor.py", line 81, in > _create_project_state > migration.mutate_state(state, preserve=False) > File > "/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site- > packages/django/db/migrations/migration.py", line 92, in mutate_state > operation.state_forwards(self.app_label, new_state) > File > "/home/logang/projects/stove/software/website_dev/env/lib/python3.4/site- > packages/django/db/migrations/operations/fields.py", line 148, in > state_forwards > delay = not old_field.is_relation > AttributeError: 'NoneType' object has no attribute 'is_relation' > > }}} New description: Hi, I'm trying to upgrade my project (originally created on 1.7) to the latest release but there's an issue with my existing migration files not working. The backtrace is below. I'll attache my migration files but it seems to be related to the migration removing the 'id' field which was automatically created and then removed in a future migration. Commenting out the RemoveField in the second migration seems to fix the issue but I'm not sure if it's entirely correct to do so. Thanks, Logan {{{ Traceback (most recent call last): File "./manage.py", line 10, in <module> execute_from_command_line(sys.argv) File "/home/logang/projects/stove/software/website_dev/env/lib/python3.4 /site-packages/django/core/management/__init__.py", line 363, in execute_from_command_line utility.execute() File "/home/logang/projects/stove/software/website_dev/env/lib/python3.4 /site-packages/django/core/management/__init__.py", line 355, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/home/logang/projects/stove/software/website_dev/env/lib/python3.4 /site-packages/django/core/management/base.py", line 283, in run_from_argv self.execute(*args, **cmd_options) File "/home/logang/projects/stove/software/website_dev/env/lib/python3.4 /site-packages/django/core/management/base.py", line 330, in execute output = self.handle(*args, **options) File "/home/logang/projects/stove/software/website_dev/env/lib/python3.4 /site-packages/django/core/management/commands/migrate.py", line 163, in handle pre_migrate_state = executor._create_project_state(with_applied_migrations=True) File "/home/logang/projects/stove/software/website_dev/env/lib/python3.4 /site-packages/django/db/migrations/executor.py", line 81, in _create_project_state migration.mutate_state(state, preserve=False) File "/home/logang/projects/stove/software/website_dev/env/lib/python3.4 /site-packages/django/db/migrations/migration.py", line 92, in mutate_state operation.state_forwards(self.app_label, new_state) File "/home/logang/projects/stove/software/website_dev/env/lib/python3.4 /site-packages/django/db/migrations/operations/fields.py", line 148, in state_forwards delay = not old_field.is_relation AttributeError: 'NoneType' object has no attribute 'is_relation' }}} -- Comment: I have the same issue like Logan. Hello, Was going from Django version 1.10.7 to 1.11.4 and my migrations were not working. All my migrations were migrated before the upgrade. I went back to 1.10.7 and it was working again. Going back to 1.11.4 same error. {{{ Traceback (most recent call last): File "manage.py", line 10, in <module> execute_from_command_line(sys.argv) File "[...]/venv/lib/python2.7/site- packages/django/core/management/__init__.py", line 363, in execute_from_command_line utility.execute() File "[...]/venv/lib/python2.7/site- packages/django/core/management/__init__.py", line 355, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "[...]/venv/lib/python2.7/site- packages/django/core/management/base.py", line 283, in run_from_argv self.execute(*args, **cmd_options) File "[...]/venv/lib/python2.7/site- packages/django/core/management/base.py", line 330, in execute output = self.handle(*args, **options) File "[...]/venv/lib/python2.7/site- packages/django/core/management/commands/migrate.py", line 163, in handle pre_migrate_state = executor._create_project_state(with_applied_migrations=True) File "/[...]/venv/lib/python2.7/site- packages/django/db/migrations/executor.py", line 81, in _create_project_state migration.mutate_state(state, preserve=False) File "[...]/venv/lib/python2.7/site- packages/django/db/migrations/migration.py", line 92, in mutate_state operation.state_forwards(self.app_label, new_state) File "[...]/venv/lib/python2.7/site- packages/django/db/migrations/operations/fields.py", line 150, in state_forwards delay = not old_field.is_relation AttributeError: 'NoneType' object has no attribute 'is_relation' }}} When I look in the fields.py file I can see on the line 139 a function: {{{ def state_forwards(self, app_label, state): new_fields = [] old_field = None for name, instance in state.models[app_label, self.model_name_lower].fields: if name != self.name: new_fields.append((name, instance)) else: old_field = instance state.models[app_label, self.model_name_lower].fields = new_fields # Delay rendering of relationships if it's not a relational field delay = not old_field.is_relation state.reload_model(app_label, self.model_name_lower, delay=delay) }}} Found out that it was crashing on 1 of the model fields that are not existing anymore in the database. I added a line to print the name of the model and field to find out what is causing the crash. If old_field = None then it is calling a method on empty variable and it throws and error. Added this line print app_label + " " + self.model_name_lower + " " + self.name {{{ def state_forwards(self, app_label, state): new_fields = [] old_field = None print app_label + " " + self.model_name_lower + " " + self.name for name, instance in state.models[app_label, self.model_name_lower].fields: if name != self.name: new_fields.append((name, instance)) else: old_field = instance state.models[app_label, self.model_name_lower].fields = new_fields # Delay rendering of relationships if it's not a relational field delay = not old_field.is_relation state.reload_model(app_label, self.model_name_lower, delay=delay) }}} The Output was {{{ cars video subtitle_url cars photos gear cars news tags Traceback (most recent call last): File "manage.py", line 10, in <module> execute_from_command_line(sys.argv) File "[...]/venv/lib/python2.7/site- packages/django/core/management/__init__.py", line 363, in execute_from_command_line utility.execute() File "[...]/venv/lib/python2.7/site- packages/django/core/management/__init__.py", line 355, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "[...]/venv/lib/python2.7/site- packages/django/core/management/base.py", line 283, in run_from_argv self.execute(*args, **cmd_options) File "[...]/venv/lib/python2.7/site- packages/django/core/management/base.py", line 330, in execute output = self.handle(*args, **options) File "[...]/venv/lib/python2.7/site- packages/django/core/management/commands/migrate.py", line 163, in handle pre_migrate_state = executor._create_project_state(with_applied_migrations=True) File "/[...]/venv/lib/python2.7/site- packages/django/db/migrations/executor.py", line 81, in _create_project_state migration.mutate_state(state, preserve=False) File "[...]/venv/lib/python2.7/site- packages/django/db/migrations/migration.py", line 92, in mutate_state operation.state_forwards(self.app_label, new_state) File "[...]/venv/lib/python2.7/site- packages/django/db/migrations/operations/fields.py", line 150, in state_forwards delay = not old_field.is_relation AttributeError: 'NoneType' object has no attribute 'is_relation' }}} That means it crashed on App[Cars] Model[News] and Field[Tags] - tags were not in the DB anymore long time ago. I found this migration: {{{ migrations.RemoveField( model_name='news', name='tags', ), }}} And deleted it. After that the migration ran 100% and I am fully functional on 1.11.4. For the record the function in 1.10.7 is - and that is working {{{ def state_forwards(self, app_label, state): new_fields = [] for name, instance in state.models[app_label, self.model_name_lower].fields: if name != self.name: new_fields.append((name, instance)) state.models[app_label, self.model_name_lower].fields = new_fields state.reload_model(app_label, self.model_name_lower) }}} 1. fields.py https://github.com/django/django/blob/master/django/db/migrations/operations/fields.py 2. Who was working on that one https://github.com/django/django/commit/45ded053b1f4320284aa5dac63052f6d1baefea9 -- Ticket URL: <https://code.djangoproject.com/ticket/28073#comment:9> Django <https://code.djangoproject.com/> The Web framework for perfectionists with deadlines. -- You received this message because you are subscribed to the Google Groups "Django updates" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-updates+unsubscr...@googlegroups.com. To post to this group, send email to django-updates@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/django-updates/065.7c4336b57ddd07d28e95b3030418aa8b%40djangoproject.com. For more options, visit https://groups.google.com/d/optout.