bug - undocumented that http_method_names requires lowercase

[bsolomon1124]

Works:

class UserViewSet(viewsets.ModelViewSet):
    http_method_names = [i.lower() for i in permissions.SAFE_METHODS]

Breaks:

class UserViewSet(viewsets.ModelViewSet):
    http_method_names = permissions.SAFE_METHODS

The lowercase version shows Allow: GET, HEAD, OPTIONS in the browser UI, while leaving SAFE_METHODS as-is with zero other changes brings back "detail": "Method \"GET\" not allowed.".

I have confirmed this is not due to list v tuple, solely due to case.

[bsolomon1124]

I believe the faulty comparison may lie here:

django-rest-framework/rest_framework/views.py

Line 499 in 71e6c30

# Get the appropriate handler method

Where the LHS is lowercased therefore assuming self.http_method_names is also lower.

[tomchristie]

I think that using uppercased names for http_method_names would result in slightly broken behaviour anyways...

Taking a look here: https://github.com/django/django/blob/main/django/views/generic/base.py#L117 - Django expects to be able to map the name directly onto the counterpart method, when determining which methods to add to the Allow header.

I'm not sure if accepting #8107 would necessarily be a great idea, because I think it'd mean that the REST framework dispatch would then start working if uppercased method names are used in http_method_names, but the Allow headers that Django generates for those views would be broken.

(I think?)