invites: Do not add user to default streams if streams list is empty.

We do not add user to the default streams if the streams list passed
while sending the invite (both email and multi-use) was empty since
invite explicitly selected to not subscribe the user to default
streams.

zerver/actions/create_user.py

@@ -182,9 +182,12 @@ def process_new_human_user(
         streams = []
         acting_user = None
 
-    # If the user's invitation didn't explicitly list some streams, we
-    # add the default streams
-    if len(streams) == 0:
+    user_was_invited = prereg_user is not None and (
+        prereg_user.referred_by is not None or prereg_user.multiuse_invite is not None
+    )
+    # If the Preregistration object didn't explicitly list some streams (it happens when user
+    # directly signs up without any invitation), we add the default streams
+    if len(streams) == 0 and not user_was_invited:
         streams = get_default_subs(user_profile)
 
     for default_stream_group in default_stream_groups:

zerver/tests/test_invite.py

@@ -25,6 +25,7 @@ from confirmation.models import (
 from corporate.lib.stripe import get_latest_seat_count
 from zerver.actions.create_realm import do_change_realm_subdomain, do_create_realm
 from zerver.actions.create_user import do_create_user, process_new_human_user
+from zerver.actions.default_streams import get_default_streams_for_realm
 from zerver.actions.invites import (
     do_create_multiuse_invite_link,
     do_get_invites_controlled_by_user,
@@ -2230,8 +2231,10 @@ class MultiuseInviteTest(ZulipTestCase):
     def test_multiuse_link_with_specified_streams(self) -> None:
         name1 = "newuser"
         name2 = "bob"
+        name3 = "alice"
         email1 = self.nonreg_email(name1)
         email2 = self.nonreg_email(name2)
+        email3 = self.nonreg_email(name3)
 
         stream_names = ["Rome", "Scotland", "Venice"]
         streams = [get_stream(stream_name, self.realm) for stream_name in stream_names]
@@ -2245,6 +2248,13 @@ class MultiuseInviteTest(ZulipTestCase):
         self.check_user_able_to_register(email2, invite_link)
         self.check_user_subscribed_only_to_streams(name2, streams)
 
+        streams = []
+        invite_link = self.generate_multiuse_invite_link(streams=streams)
+        self.check_user_able_to_register(email3, invite_link)
+        # User is not subscribed to default streams as well.
+        self.assert_length(get_default_streams_for_realm(self.realm.id), 1)
+        self.check_user_subscribed_only_to_streams(name3, [])
+
     def test_multiuse_link_different_realms(self) -> None:
         """
         Verify that an invitation generated for one realm can't be used
@@ -2299,6 +2309,21 @@ class MultiuseInviteTest(ZulipTestCase):
         self.check_user_able_to_register(self.nonreg_email("test"), invite_link)
         self.check_user_subscribed_only_to_streams("test", streams)
 
+        self.login("iago")
+        stream_ids = []
+        result = self.client_post(
+            "/json/invites/multiuse",
+            {
+                "stream_ids": orjson.dumps(stream_ids).decode(),
+                "invite_expires_in_minutes": 2 * 24 * 60,
+            },
+        )
+        invite_link = self.assert_json_success(result)["invite_link"]
+        self.check_user_able_to_register(self.nonreg_email("alice"), invite_link)
+        # User is not subscribed to default streams as well.
+        self.assert_length(get_default_streams_for_realm(self.realm.id), 1)
+        self.check_user_subscribed_only_to_streams("alice", [])
+
     def test_only_admin_can_create_multiuse_link_api_call(self) -> None:
         self.login("iago")
         # Only admins should be able to create multiuse invites even if