export: Handle RealmAuditLog with .acting_user in different realm.

zerver/lib/export.py

@@ -713,9 +713,8 @@ def get_realm_config() -> Config:
 
     Config(
         table="zerver_realmauditlog",
-        model=RealmAuditLog,
-        normal_parent=realm_config,
-        include_rows="realm_id__in",
+        virtual_parent=realm_config,
+        custom_fetch=custom_fetch_realm_audit_logs_for_realm,
     )
 
     Config(
@@ -1152,6 +1151,30 @@ def custom_fetch_scheduled_messages(response: TableData, context: Context) -> No
     response["zerver_scheduledmessage"] = rows
 
 
+def custom_fetch_realm_audit_logs_for_realm(response: TableData, context: Context) -> None:
+    """
+    Simple custom fetch function to fix up .acting_user for some RealmAuditLog objects.
+
+    Certain RealmAuditLog objects have an acting_user that is in a different .realm, due to
+    the possibility of server administrators (typically with the .is_staff permission) taking
+    certain actions to modify UserProfiles or Realms, which will set the .acting_user to
+    the administrator's UserProfile, which can be in a different realm. Such an acting_user
+    cannot be imported during organization import on another server, so we need to just set it
+    to None.
+    """
+    realm = context["realm"]
+
+    query = RealmAuditLog.objects.filter(realm=realm).select_related("acting_user")
+    realmauditlog_objects = list(query)
+    for realmauditlog in realmauditlog_objects:
+        if realmauditlog.acting_user is not None and realmauditlog.acting_user.realm_id != realm.id:
+            realmauditlog.acting_user = None
+
+    rows = make_raw(realmauditlog_objects)
+
+    response["zerver_realmauditlog"] = rows
+
+
 def fetch_usermessages(
     realm: Realm,
     message_ids: Set[int],

zerver/tests/test_import_export.py

@@ -83,6 +83,8 @@ from zerver.models import (
     get_huddle_hash,
     get_realm,
     get_stream,
+    get_system_bot,
+    get_user_by_delivery_email,
 )
 
 
@@ -708,6 +710,9 @@ class RealmImportExportTest(ExportFile):
         cordelia = self.example_user("cordelia")
         othello = self.example_user("othello")
 
+        internal_realm = get_realm(settings.SYSTEM_BOT_REALM)
+        cross_realm_bot = get_system_bot(settings.WELCOME_BOT, internal_realm.id)
+
         with get_test_image_file("img.png") as img_file:
             realm_emoji = check_add_realm_emoji(
                 realm=hamlet.realm, name="hawaii", author=hamlet, image_file=img_file
@@ -728,6 +733,18 @@ class RealmImportExportTest(ExportFile):
             original_realm, authentication_methods, acting_user=None
         )
 
+        # Set up an edge-case RealmAuditLog with acting_user in a different realm. Such an acting_user can't be covered
+        # by the export, so we'll test that it is handled by getting set to None.
+        self.assertTrue(
+            RealmAuditLog.objects.filter(
+                modified_user=hamlet, event_type=RealmAuditLog.USER_CREATED
+            ).count(),
+            1,
+        )
+        RealmAuditLog.objects.filter(
+            modified_user=hamlet, event_type=RealmAuditLog.USER_CREATED
+        ).update(acting_user_id=cross_realm_bot.id)
+
         # data to test import of huddles
         huddle = [
             self.example_user("hamlet"),
@@ -989,6 +1006,15 @@ class RealmImportExportTest(ExportFile):
             imported_realm.authentication_methods_dict(),
         )
 
+        imported_hamlet = get_user_by_delivery_email(hamlet.delivery_email, imported_realm)
+        realmauditlog = RealmAuditLog.objects.get(
+            modified_user=imported_hamlet, event_type=RealmAuditLog.USER_CREATED
+        )
+        self.assertEqual(realmauditlog.realm, imported_realm)
+        # As explained above when setting up the RealmAuditLog row, the .acting_user should have been
+        # set to None due to being unexportable.
+        self.assertEqual(realmauditlog.acting_user, None)
+
         self.assertEqual(
             Message.objects.filter(realm=original_realm).count(),
             Message.objects.filter(realm=imported_realm).count(),