mypy and django models: how to detect errors on nonexistent attributes
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2
down vote
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Consider this model definition and usage:
from django.db import models
class User(models.Model):
name: str = models.CharField(max_length=100)
def do_stuff(user: User) -> None:
# accessing existing field
print(user.name.strip())
# accessing existing field with a wrong operation: will fail at runtime
print(user.name + 1)
# acessing nonexistent field: will fail at runtime
print(user.name_abc.strip())
While running mypy on this, we will get an error for user.name + 1:
error: Unsupported operand types for + ("str" and "int")
This is fine. But there's another error in the code - user.name_abc does not exist and will result in AttributeError in runtime.
However, mypy will not see this because it lets the code access any django attributes, also treating them as Any:
u = User(name='abc')
reveal_type(user.abcdef)
....
> error: Revealed type is 'Any
So, how do I make mypy see such errors?
django mypy
asked Nov 19 at 7:51
kurtgn
1,71521938
add a comment |
up vote
2
down vote
favorite
Consider this model definition and usage:
from django.db import models
class User(models.Model):
name: str = models.CharField(max_length=100)
def do_stuff(user: User) -> None:
# accessing existing field
print(user.name.strip())
# accessing existing field with a wrong operation: will fail at runtime
print(user.name + 1)
# acessing nonexistent field: will fail at runtime
print(user.name_abc.strip())
While running mypy on this, we will get an error for user.name + 1:
error: Unsupported operand types for + ("str" and "int")
This is fine. But there's another error in the code - user.name_abc does not exist and will result in AttributeError in runtime.
However, mypy will not see this because it lets the code access any django attributes, also treating them as Any:
u = User(name='abc')
reveal_type(user.abcdef)
....
> error: Revealed type is 'Any
So, how do I make mypy see such errors?
django mypy
asked Nov 19 at 7:51
kurtgn
1,71521938
It seems that this is related to the Django model class, not yours. If you are not subclassing Django model you get an error: stackoverflow.com/questions/50889677/…
– danielfranca
Nov 19 at 8:55
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 at 10:28
add a comment |
up vote
2
down vote
favorite
up vote
2
down vote
favorite
Consider this model definition and usage:
from django.db import models
class User(models.Model):
name: str = models.CharField(max_length=100)
def do_stuff(user: User) -> None:
# accessing existing field
print(user.name.strip())
# accessing existing field with a wrong operation: will fail at runtime
print(user.name + 1)
# acessing nonexistent field: will fail at runtime
print(user.name_abc.strip())
While running mypy on this, we will get an error for user.name + 1:
error: Unsupported operand types for + ("str" and "int")
This is fine. But there's another error in the code - user.name_abc does not exist and will result in AttributeError in runtime.
However, mypy will not see this because it lets the code access any django attributes, also treating them as Any:
u = User(name='abc')
reveal_type(user.abcdef)
....
> error: Revealed type is 'Any
So, how do I make mypy see such errors?
django mypy
asked Nov 19 at 7:51
kurtgn
1,71521938
Consider this model definition and usage:
from django.db import models
class User(models.Model):
name: str = models.CharField(max_length=100)
def do_stuff(user: User) -> None:
# accessing existing field
print(user.name.strip())
# accessing existing field with a wrong operation: will fail at runtime
print(user.name + 1)
# acessing nonexistent field: will fail at runtime
print(user.name_abc.strip())
While running mypy on this, we will get an error for user.name + 1:
error: Unsupported operand types for + ("str" and "int")
This is fine. But there's another error in the code - user.name_abc does not exist and will result in AttributeError in runtime.
However, mypy will not see this because it lets the code access any django attributes, also treating them as Any:
u = User(name='abc')
reveal_type(user.abcdef)
....
> error: Revealed type is 'Any
So, how do I make mypy see such errors?
django mypy
django mypy
asked Nov 19 at 7:51
kurtgn
1,71521938
asked Nov 19 at 7:51
kurtgn
1,71521938
asked Nov 19 at 7:51
kurtgn
1,71521938
asked Nov 19 at 7:51
kurtgn
1,71521938
asked Nov 19 at 7:51
kurtgn
1,71521938
1,71521938
It seems that this is related to the Django model class, not yours. If you are not subclassing Django model you get an error: stackoverflow.com/questions/50889677/…
– danielfranca
Nov 19 at 8:55
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 at 10:28
add a comment |
It seems that this is related to the Django model class, not yours. If you are not subclassing Django model you get an error: stackoverflow.com/questions/50889677/…
– danielfranca
Nov 19 at 8:55
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 at 10:28
It seems that this is related to the Django model class, not yours. If you are not subclassing Django model you get an error: stackoverflow.com/questions/50889677/…
– danielfranca
Nov 19 at 8:55
It seems that this is related to the Django model class, not yours. If you are not subclassing Django model you get an error: stackoverflow.com/questions/50889677/…
– danielfranca
Nov 19 at 8:55
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 at 10:28
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 at 10:28
add a comment |
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It seems that this is related to the Django model class, not yours. If you are not subclassing Django model you get an error: stackoverflow.com/questions/50889677/…
– danielfranca
Nov 19 at 8:55
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 at 10:28