deprecate add_custom_404_page (#4505)

* deprecate add_custom_404_page

* show raw value in deprecate message

* fix typo

* Update reflex/app.py

Co-authored-by: Masen Furer <m_github@0x26.net>

* change removal version to 0.8.0

---------

Co-authored-by: Masen Furer <m_github@0x26.net>

reflex/app.py

@@ -468,7 +468,7 @@ class App(MiddlewareMixin, LifespanMixin):
 
     def add_page(
         self,
-        component: Component | ComponentCallable,
+        component: Component | ComponentCallable | None = None,
         route: str | None = None,
         title: str | Var | None = None,
         description: str | Var | None = None,
@@ -491,17 +491,33 @@ class App(MiddlewareMixin, LifespanMixin):
             meta: The metadata of the page.
 
         Raises:
-            ValueError: When the specified route name already exists.
+            PageValueError: When the component is not set for a non-404 page.
+            RouteValueError: When the specified route name already exists.
         """
         # If the route is not set, get it from the callable.
         if route is None:
             if not isinstance(component, Callable):
-                raise ValueError("Route must be set if component is not a callable.")
+                raise exceptions.RouteValueError(
+                    "Route must be set if component is not a callable."
+                )
             # Format the route.
             route = format.format_route(component.__name__)
         else:
             route = format.format_route(route, format_case=False)
 
+        if route == constants.Page404.SLUG:
+            if component is None:
+                component = Default404Page.create()
+            component = wait_for_client_redirect(self._generate_component(component))
+            title = title or constants.Page404.TITLE
+            description = description or constants.Page404.DESCRIPTION
+            image = image or constants.Page404.IMAGE
+        else:
+            if component is None:
+                raise exceptions.PageValueError(
+                    "Component must be set for a non-404 page."
+                )
+
         # Check if the route given is valid
         verify_route_validity(route)
 
@@ -517,7 +533,7 @@ class App(MiddlewareMixin, LifespanMixin):
                 if route == constants.PageNames.INDEX_ROUTE
                 else f"`{route}`"
             )
-            raise ValueError(
+            raise exceptions.RouteValueError(
                 f"Duplicate page route {route_name} already exists. Make sure you do not have two"
                 f" pages with the same route"
             )
@@ -634,10 +650,14 @@ class App(MiddlewareMixin, LifespanMixin):
             on_load: The event handler(s) that will be called each time the page load.
             meta: The metadata of the page.
         """
-        if component is None:
+        console.deprecate(
-            component = Default404Page.create()
+            feature_name="App.add_custom_404_page",
+            reason=f"Use app.add_page(component, route='/{constants.Page404.SLUG}') instead.",
+            deprecation_version="0.6.7",
+            removal_version="0.8.0",
+        )
         self.add_page(
-            component=wait_for_client_redirect(self._generate_component(component)),
+            component=component,
             route=constants.Page404.SLUG,
             title=title or constants.Page404.TITLE,
             image=image or constants.Page404.IMAGE,
@@ -838,7 +858,7 @@ class App(MiddlewareMixin, LifespanMixin):
 
         # Render a default 404 page if the user didn't supply one
         if constants.Page404.SLUG not in self.unevaluated_pages:
-            self.add_custom_404_page()
+            self.add_page(route=constants.Page404.SLUG)
 
         # Fix up the style.
         self.style = evaluate_style_namespaces(self.style)

reflex/components/core/client_side_routing.py

@@ -24,7 +24,7 @@ class ClientSideRouting(Component):
     library = "$/utils/client_side_routing"
     tag = "useClientSideRouting"
 
-    def add_hooks(self) -> list[str]:
+    def add_hooks(self) -> list[str | Var]:
         """Get the hooks to render.
 
         Returns:
@@ -66,4 +66,4 @@ class Default404Page(Component):
     tag = "Error"
     is_default = True
 
-    status_code: Var[int] = 404  # type: ignore
+    status_code: Var[int] = Var.create(404)

reflex/components/core/client_side_routing.pyi

@@ -13,7 +13,7 @@ from reflex.vars.base import Var
 route_not_found: Var
 
 class ClientSideRouting(Component):
-    def add_hooks(self) -> list[str]: ...
+    def add_hooks(self) -> list[str | Var]: ...
     def render(self) -> str: ...
     @overload
     @classmethod

reflex/utils/exceptions.py

@@ -63,6 +63,10 @@ class UploadValueError(ReflexError, ValueError):
     """Custom ValueError for upload related errors."""
 
 
+class PageValueError(ReflexError, ValueError):
+    """Custom ValueError for page related errors."""
+
+
 class RouteValueError(ReflexError, ValueError):
     """Custom ValueError for route related errors."""