'NoneType' object has no attribute 'negate' [duplicate] - python-3.x

Question

This question already has answers here:
Why do I get AttributeError: 'NoneType' object has no attribute 'something'?
(11 answers)
Closed 1 year ago.
I'm getting the error when trying to get all the Urls for which the limited field is True. I've tried deleting the migrations and creating new migrations, but still getting the same error.
these are the installed dependencies:
asgiref==3.4.1
backports.zoneinfo==0.2.1
Django==4.0
django-cors-headers==3.10.1
django-shell-plus==1.1.7
djangorestframework==3.13.1
djongo==1.3.6
dnspython==2.1.0
gunicorn==20.1.0
pymongo==3.12.1
python-dotenv==0.19.2
pytz==2021.3
sqlparse==0.2.4
tzdata==2021.5
models.py:
class Urls(models.Model):
_id = models.ObjectIdField()
record_id = models.IntegerField(unique=True)
hash = models.CharField(unique=True, max_length=1000)
long_url = models.URLField()
created_at = models.DateField(auto_now_add=True)
expires_in = models.DurationField(default=timedelta(days=365*3))
expires_on = models.DateField(null=True, blank=True)
limited = models.BooleanField()
exhausted = models.BooleanField()
query:
Urls.objects.filter(limited=False)
error:
Traceback (most recent call last):
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 857, in parse
return handler(self, statement)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 933, in _select
return SelectQuery(self.db, self.connection_properties, sm, self._params)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 116, in __init__
super().__init__(*args)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 62, in __init__
self.parse()
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 152, in parse
self.where = WhereConverter(self, statement)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/converters.py", line 27, in __init__
self.parse()
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/converters.py", line 119, in parse
self.op = WhereOp(
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/operators.py", line 476, in __init__
self.evaluate()
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/operators.py", line 465, in evaluate
op.evaluate()
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/operators.py", line 258, in evaluate
self.rhs.negate()
AttributeError: 'NoneType' object has no attribute 'negate'
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/cursor.py", line 51, in execute
self.result = Query(
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 784, in __init__
self._query = self.parse()
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 885, in parse
raise exe from e
djongo.exceptions.SQLDecodeError:
Keyword: None
Sub SQL: None
FAILED SQL: SELECT "short_urls"."_id", "short_urls"."record_id", "short_urls"."hash", "short_urls"."long_url", "short_urls"."created_at", "short_urls"."expires_in", "short_urls"."expires_on", "short_urls"."limited", "short_urls"."exhausted" FROM "short_urls" WHERE NOT "short_urls"."limited" LIMIT 21
Params: ()
Version: 1.3.6
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 85, in _execute
return self.cursor.execute(sql, params)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/cursor.py", line 59, in execute
raise db_exe from e
djongo.database.DatabaseError
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/models/query.py", line 256, in __repr__
data = list(self[:REPR_OUTPUT_SIZE + 1])
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/models/query.py", line 262, in __len__
self._fetch_all()
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/models/query.py", line 1354, in _fetch_all
self._result_cache = list(self._iterable_class(self))
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/models/query.py", line 51, in __iter__
results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1202, in execute_sql
cursor.execute(sql, params)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 99, in execute
return super().execute(sql, params)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 67, in execute
return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 76, in _execute_with_wrappers
return executor(sql, params, many, context)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 85, in _execute
return self.cursor.execute(sql, params)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/utils.py", line 90, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 85, in _execute
return self.cursor.execute(sql, params)
File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/cursor.py", line 59, in execute
raise db_exe from e
django.db.utils.DatabaseError

Answer 1

I would need to see your views.py where you do that query, Urls.objects.filter(limited=False) but first, perhaps the query is not finding any Urls objects that match the criteria, limited=False, thus the query returns None, which has no attributes. Second, I'm not familiar with negate. I don't see it in your model. Perhaps if I see the views.py where you make that query I will understand better.