from allauth.socialaccount.providers.base import ProviderAccount
from allauth.socialaccount.providers.oauth2.provider import OAuth2Provider


class RedditAccount(ProviderAccount):
    def to_str(self):
        dflt = super(RedditAccount, self).to_str()
        name = self.account.extra_data.get("name", dflt)
        return name


class RedditProvider(OAuth2Provider):
    id = "reddit"
    name = "Reddit"
    account_class = RedditAccount

    def extract_uid(self, data):
        return data["name"]

    def extract_common_fields(self, data):
        return dict(name=data.get("name"))

    def get_default_scope(self):
        scope = ["identity"]
        return scope


provider_classes = [RedditProvider]

from allauth.socialaccount.providers.base import ProviderAccount
from allauth.socialaccount.providers.oauth2.provider import OAuth2Provider


class RedditAccount(ProviderAccount):
    def to_str(self):
        dflt = super(RedditAccount, self).to_str()
        name = self.account.extra_data.get("name", dflt)
        return name


class RedditProvider(OAuth2Provider):
    id = "reddit"
    name = "Reddit"
    account_class = RedditAccount

    def extract_uid(self, data):
        return data["name"]

    def extract_common_fields(self, data):
        return dict(username=data.get("name"))

    def get_default_scope(self):
        scope = ["identity"]
        return scope


provider_classes = [RedditProvider]

Use Reddit name as username