def delete_all_later_duplicate_subdomains()

in emails/migrations/0030_check_and_fix_any_duplicate_subdomains.py [0:0]

• 50 lines of code
• 9 McCabe index (conditional complexity)

def delete_all_later_duplicate_subdomains(apps, schema_editor):
    Profile = apps.get_model("emails", "Profile")
    RegisteredSubdomain = apps.get_model("emails", "RegisteredSubdomain")
    profiles_with_subdomain = (
        Profile.objects.all().exclude(subdomain=None).order_by("user__date_joined")
    )

    # find all duplicate subdomains
    duplicate_subdomains = set()
    for profile in profiles_with_subdomain:
        num_later_subdomain_registrations = Profile.objects.filter(
            subdomain__iexact=profile.subdomain,  # check this
            user__date_joined__gt=profile.user.date_joined,
        ).count()
        if num_later_subdomain_registrations > 0:
            duplicate_subdomains.add(profile.subdomain.lower())

    # remove duplicate subdomains
    for dupe in duplicate_subdomains:
        profile = (
            Profile.objects.filter(subdomain__iexact=dupe)
            .order_by("user__date_joined")
            .first()
        )
        later_subdomain_registrations = Profile.objects.filter(
            subdomain__iexact=profile.subdomain,
            user__date_joined__gt=profile.user.date_joined,
        )
        print(
            "found case-insensitive duplicate subdomains of "
            + f"{profile.user.username}"
        )
        for dupe_subdomain_profile in later_subdomain_registrations:
            # empty out the subdomain of any new profiles that were
            # erroneously allowed to register a duplicate subdomain
            print(
                "clearing subdomain for: " + f"{dupe_subdomain_profile.user.username}"
            )
            dupe_subdomain_profile.subdomain = None
            dupe_subdomain_profile.save()

    # lowercase all subdomains and
    # create RegisteredSubdomain for the lower cased subdomain
    reduced_profiles_with_subdomain = (
        Profile.objects.all().exclude(subdomain=None).order_by("user__date_joined")
    )
    for oldest_profile in reduced_profiles_with_subdomain:
        # lowercase subdomain of every profile
        oldest_profile.subdomain = oldest_profile.subdomain.lower()
        oldest_profile.save()

        registered_subdomain_exists = (
            RegisteredSubdomain.objects.filter(
                subdomain_hash=hash_subdomain(oldest_profile.subdomain)
            ).count()
            > 0
        )
        if not registered_subdomain_exists:
            RegisteredSubdomain.objects.create(
                subdomain_hash=hash_subdomain(oldest_profile.subdomain)
            )