mypy and django models: how to detect errors on nonexistent attributes
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
add a comment |
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
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 '18 at 8:55
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 '18 at 10:28
add a comment |
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
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 '18 at 7:51
kurtgnkurtgn
1,78122040
1,78122040
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 '18 at 8:55
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 '18 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 '18 at 8:55
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 '18 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 '18 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 '18 at 8:55
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 '18 at 10:28
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 '18 at 10:28
add a comment |
0
active
oldest
votes
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53370377%2fmypy-and-django-models-how-to-detect-errors-on-nonexistent-attributes%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
0
active
oldest
votes
0
active
oldest
votes
active
oldest
votes
active
oldest
votes
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53370377%2fmypy-and-django-models-how-to-detect-errors-on-nonexistent-attributes%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
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 '18 at 8:55
@danielfranca exactly. This is related to django models. The question is - how do I work around it.
– kurtgn
Nov 19 '18 at 10:28