migrations: Fix old dummy user addresses without email visibility.

We changed the format used for newly generated addresses in
fcc8debc3a but we also need to fix it for
old UserProfiles to be consistent.

zerver/migrations/0325_fix_user_dummy_emails.py

@@ -0,0 +1,86 @@
+from typing import Any
+
+from django.conf import settings
+from django.core.validators import ValidationError, validate_email
+from django.db import migrations, transaction
+from django.db.backends.postgresql.schema import DatabaseSchemaEditor
+from django.db.migrations.state import StateApps
+
+# The helper functions below are taken from models.py
+# without any functional changes, they're just a workaround
+# for the lack of access to Realm methods in migrations.
+
+
+def host_for_subdomain(subdomain: str) -> str:
+    if subdomain == "":
+        return settings.EXTERNAL_HOST
+    default_host = f"{subdomain}.{settings.EXTERNAL_HOST}"
+    return settings.REALM_HOSTS.get(subdomain, default_host)
+
+
+def get_realm_host(realm: Any) -> str:
+    return host_for_subdomain(realm.string_id)
+
+
+def get_fake_email_domain(realm: Any) -> str:
+    try:
+        # Check that realm.host can be used to form valid email addresses.
+        host = get_realm_host(realm)
+        validate_email(f"bot@{host}")
+        return host
+    except ValidationError:
+        pass
+
+    try:
+        # Check that the fake email domain can be used to form valid email addresses.
+        validate_email("bot@" + settings.FAKE_EMAIL_DOMAIN)
+    except ValidationError:
+        raise Exception(
+            settings.FAKE_EMAIL_DOMAIN + " is not a valid domain. "
+            "Consider setting the FAKE_EMAIL_DOMAIN setting."
+        )
+
+    return settings.FAKE_EMAIL_DOMAIN
+
+
+def fix_user_emails(apps: StateApps, schema_editor: DatabaseSchemaEditor) -> None:
+    EMAIL_ADDRESS_VISIBILITY_EVERYONE = 1
+    UserProfile = apps.get_model("zerver", "UserProfile")
+
+    BATCH_SIZE = 200
+    last_id = 0
+    while True:
+        with transaction.atomic():
+            user_profiles = list(
+                UserProfile.objects.exclude(
+                    realm__email_address_visibility=EMAIL_ADDRESS_VISIBILITY_EVERYONE
+                )
+                .filter(
+                    email__iregex=r"^user\d+" + f"@{settings.FAKE_EMAIL_DOMAIN}$", id__gt=last_id
+                )
+                .select_for_update()
+                .order_by("id")[:BATCH_SIZE]
+            )
+            if not user_profiles:
+                # Nothing left to fix.
+                break
+            last_id = user_profiles[-1].id
+
+            for user_profile in user_profiles:
+                user_profile.email = (
+                    f"user{user_profile.id}@{get_fake_email_domain(user_profile.realm)}"
+                )
+
+            UserProfile.objects.bulk_update(user_profiles, ["email"])
+
+
+class Migration(migrations.Migration):
+    atomic = False
+
+    dependencies = [
+        ("zerver", "0324_fix_deletion_cascade_behavior"),
+    ]
+
+    operations = [
+        migrations.RunPython(fix_user_emails, reverse_code=migrations.RunPython.noop),
+    ]