Fix reactivated users not being added to the user directory (#10782)

Co-authored-by: Dirk Klimpel <5740567+dklimpel@users.noreply.github.com>
Co-authored-by: reivilibre <olivier@librepush.net>
Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

3 files changed, 48 insertions, 4 deletions

diff --git a/changelog.d/10782.bugfix b/changelog.d/10782.bugfix
new file mode 100644
index 0000000000..3e410447cc
--- /dev/null
+++ b/changelog.d/10782.bugfix
@@ -0,0 +1 @@
+Fix a long-standing bug which caused deactivated users that were later reactivated to be missing from the user directory.
\ No newline at end of file
diff --git a/synapse/handlers/deactivate_account.py b/synapse/handlers/deactivate_account.py
index a03ff9842b..9ae5b7750e 100644
--- a/synapse/handlers/deactivate_account.py
+++ b/synapse/handlers/deactivate_account.py
@@ -255,13 +255,16 @@ class DeactivateAccountHandler(BaseHandler):
         Args:
             user_id: ID of user to be re-activated
         """
-        # Add the user to the directory, if necessary.
         user = UserID.from_string(user_id)
-        profile = await self.store.get_profileinfo(user.localpart)
-        await self.user_directory_handler.handle_local_profile_change(user_id, profile)
 
         # Ensure the user is not marked as erased.
         await self.store.mark_user_not_erased(user_id)
 
         # Mark the user as active.
         await self.store.set_user_deactivated_status(user_id, False)
+
+        # Add the user to the directory, if necessary. Note that
+        # this must be done after the user is re-activated, because
+        # deactivated users are excluded from the user directory.
+        profile = await self.store.get_profileinfo(user.localpart)
+        await self.user_directory_handler.handle_local_profile_change(user_id, profile)
diff --git a/tests/handlers/test_user_directory.py b/tests/handlers/test_user_directory.py
index ae88ed89aa..f3684c34a2 100644
--- a/tests/handlers/test_user_directory.py
+++ b/tests/handlers/test_user_directory.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from unittest.mock import Mock
+from urllib.parse import quote
 
 from twisted.internet import defer
 
@@ -20,6 +21,7 @@ from synapse.api.constants import UserTypes
 from synapse.api.room_versions import RoomVersion, RoomVersions
 from synapse.rest.client import login, room, user_directory
 from synapse.storage.roommember import ProfileInfo
+from synapse.types import create_requester
 
 from tests import unittest
 from tests.unittest import override_config
@@ -32,7 +34,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
 
     servlets = [
         login.register_servlets,
-        synapse.rest.admin.register_servlets_for_client_rest_resource,
+        synapse.rest.admin.register_servlets,
         room.register_servlets,
     ]
 
@@ -130,6 +132,44 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
         self.get_success(self.handler.handle_local_user_deactivated(r_user_id))
         self.store.remove_from_user_dir.called_once_with(r_user_id)
 
+    def test_reactivation_makes_regular_user_searchable(self):
+        user = self.register_user("regular", "pass")
+        user_token = self.login(user, "pass")
+        admin_user = self.register_user("admin", "pass", admin=True)
+        admin_token = self.login(admin_user, "pass")
+
+        # Ensure the regular user is publicly visible and searchable.
+        self.helper.create_room_as(user, is_public=True, tok=user_token)
+        s = self.get_success(self.handler.search_users(admin_user, user, 10))
+        self.assertEqual(len(s["results"]), 1)
+        self.assertEqual(s["results"][0]["user_id"], user)
+
+        # Deactivate the user and check they're not searchable.
+        deactivate_handler = self.hs.get_deactivate_account_handler()
+        self.get_success(
+            deactivate_handler.deactivate_account(
+                user, erase_data=False, requester=create_requester(admin_user)
+            )
+        )
+        s = self.get_success(self.handler.search_users(admin_user, user, 10))
+        self.assertEqual(s["results"], [])
+
+        # Reactivate the user
+        channel = self.make_request(
+            "PUT",
+            f"/_synapse/admin/v2/users/{quote(user)}",
+            access_token=admin_token,
+            content={"deactivated": False, "password": "pass"},
+        )
+        self.assertEqual(channel.code, 200)
+        user_token = self.login(user, "pass")
+        self.helper.create_room_as(user, is_public=True, tok=user_token)
+
+        # Check they're searchable.
+        s = self.get_success(self.handler.search_users(admin_user, user, 10))
+        self.assertEqual(len(s["results"]), 1)
+        self.assertEqual(s["results"][0]["user_id"], user)
+
     def test_private_room(self):
         """
         A user can be searched for only by people that are either in a public