From f5e4846cfa32295d6ebba511f99cae92c743c8f2 Mon Sep 17 00:00:00 2001
From: Min RK <benjaminrk@gmail.com>
Date: Tue, 26 Apr 2022 15:15:55 +0200
Subject: [PATCH] Backport PR #3874: Missing `f` prefix on f-strings fix

Fixes  3873

Signed-off-by: Min RK <benjaminrk@gmail.com>
---
 jupyterhub/apihandlers/groups.py |  2 +-
 jupyterhub/apihandlers/users.py  |  2 +-
 jupyterhub/handlers/pages.py     |  2 +-
 jupyterhub/spawner.py            | 13 +++++++++----
 jupyterhub/user.py               |  4 ++--
 5 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/jupyterhub/apihandlers/groups.py b/jupyterhub/apihandlers/groups.py
index dbe9fec2..f36ad669 100644
--- a/jupyterhub/apihandlers/groups.py
+++ b/jupyterhub/apihandlers/groups.py
@@ -50,7 +50,7 @@ class GroupListAPIHandler(_GroupAPIHandler):
                 # the only valid filter is group=...
                 # don't expand invalid !server=x to all groups!
                 self.log.warning(
-                    "Invalid filter on list:group for {self.current_user}: {sub_scope}"
+                    f"Invalid filter on list:group for {self.current_user}: {sub_scope}"
                 )
                 raise web.HTTPError(403)
             query = query.filter(orm.Group.name.in_(sub_scope['group']))
diff --git a/jupyterhub/apihandlers/users.py b/jupyterhub/apihandlers/users.py
index 109ad32a..167b0592 100644
--- a/jupyterhub/apihandlers/users.py
+++ b/jupyterhub/apihandlers/users.py
@@ -131,7 +131,7 @@ class UserListAPIHandler(APIHandler):
             if not set(sub_scope).issubset({'group', 'user'}):
                 # don't expand invalid !server=x filter to all users!
                 self.log.warning(
-                    "Invalid filter on list:user for {self.current_user}: {sub_scope}"
+                    f"Invalid filter on list:user for {self.current_user}: {sub_scope}"
                 )
                 raise web.HTTPError(403)
             filters = []
diff --git a/jupyterhub/handlers/pages.py b/jupyterhub/handlers/pages.py
index cd311375..052b29e1 100644
--- a/jupyterhub/handlers/pages.py
+++ b/jupyterhub/handlers/pages.py
@@ -498,7 +498,7 @@ class TokenPageHandler(BaseHandler):
                 continue
             if not token.client_id:
                 # token should have been deleted when client was deleted
-                self.log.warning("Deleting stale oauth token {token}")
+                self.log.warning(f"Deleting stale oauth token {token}")
                 self.db.delete(token)
                 self.db.commit()
                 continue
diff --git a/jupyterhub/spawner.py b/jupyterhub/spawner.py
index 5b816e75..23c18895 100644
--- a/jupyterhub/spawner.py
+++ b/jupyterhub/spawner.py
@@ -97,10 +97,15 @@ class Spawner(LoggingConfigurable):
 
         Used in logging for consistency with named servers.
         """
-        if self.name:
-            return f'{self.user.name}:{self.name}'
+        if self.user:
+            user_name = self.user.name
         else:
-            return self.user.name
+            # no user, only happens in mock tests
+            user_name = "(no user)"
+        if self.name:
+            return f"{user_name}:{self.name}"
+        else:
+            return user_name
 
     @property
     def _failed(self):
@@ -228,7 +233,7 @@ class Spawner(LoggingConfigurable):
                 self.orm_spawner.server = server.orm_server
         elif server is not None:
             self.log.warning(
-                "Setting Spawner.server for {self._log_name} with no underlying orm_spawner"
+                f"Setting Spawner.server for {self._log_name} with no underlying orm_spawner"
             )
 
     @property
diff --git a/jupyterhub/user.py b/jupyterhub/user.py
index 71ee6ce5..22181611 100644
--- a/jupyterhub/user.py
+++ b/jupyterhub/user.py
@@ -282,9 +282,9 @@ class User:
         new_groups = set(group_names).difference(current_groups)
         removed_groups = current_groups.difference(group_names)
         if new_groups:
-            self.log.info("Adding user {self.name} to group(s): {new_groups}")
+            self.log.info(f"Adding user {self.name} to group(s): {new_groups}")
         if removed_groups:
-            self.log.info("Removing user {self.name} from group(s): {removed_groups}")
+            self.log.info(f"Removing user {self.name} from group(s): {removed_groups}")
 
         if group_names:
             groups = (