From 72e1464c09cd35ba10f2dcdd0e12422c4c8e7972 Mon Sep 17 00:00:00 2001
From: Jeremy Tuloup <jeremy.tuloup@gmail.com>
Date: Tue, 26 Apr 2022 19:43:55 +0200
Subject: [PATCH] Do not mutate existing page config

---
 notebook/app.py | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/notebook/app.py b/notebook/app.py
index c06fd7ed5..74a0805b8 100644
--- a/notebook/app.py
+++ b/notebook/app.py
@@ -32,19 +32,18 @@ class NotebookBaseHandler(ExtensionHandlerJinjaMixin, ExtensionHandlerMixin, Jup
         config = LabConfig()
         app = self.extensionapp
         base_url = self.settings.get("base_url")
-        page_config = self.settings.setdefault("page_config_data", {})
-        page_config.update(
-            {
-                "appVersion": version,
-                "baseUrl": self.base_url,
-                "terminalsAvailable": self.settings.get("terminals_available", False),
-                "token": self.settings["token"],
-                "fullStaticUrl": ujoin(self.base_url, "static", self.name),
-                "frontendUrl": ujoin(self.base_url, "/"),
-                "exposeAppInBrowser": app.expose_app_in_browser,
-                "collaborative": app.collaborative,
-            }
-        )
+        page_config_data = self.settings.setdefault("page_config_data", {})
+        page_config = {
+            **page_config_data,
+            "appVersion": version,
+            "baseUrl": self.base_url,
+            "terminalsAvailable": self.settings.get("terminals_available", False),
+            "token": self.settings["token"],
+            "fullStaticUrl": ujoin(self.base_url, "static", self.name),
+            "frontendUrl": ujoin(self.base_url, "/"),
+            "exposeAppInBrowser": app.expose_app_in_browser,
+            "collaborative": app.collaborative,
+        }
 
         if "hub_prefix" in app.serverapp.tornado_settings:
             tornado_settings = app.serverapp.tornado_settings