disable react strict mode for event loop (#4720)

* disable react strict mode for event loop

* oops

* pyi oui

* separate socket connection from event loop

* prettier state.js

* disable react strict mode

* didn't work sadge

* socket connect/disconnect depends on new isBackendDisabled state

* only start the event loop when the socket is set or we're not stateful

* Always drain the queue unless backend is disabled

---------

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

reflex/.templates/jinja/web/pages/_app.js.jinja2

@@ -38,13 +38,13 @@ export default function MyApp({ Component, pageProps }) {
   }, []);
   return (
     <ThemeProvider defaultTheme={ defaultColorMode } attribute="class">
-      <AppWrap>
-        <StateProvider>
-          <EventLoopProvider>
-            <Component {...pageProps} />
-          </EventLoopProvider>
-        </StateProvider>
-      </AppWrap>
+      <StateProvider>
+        <EventLoopProvider>
+            <AppWrap>
+              <Component {...pageProps} />
+            </AppWrap>
+        </EventLoopProvider>
+      </StateProvider>
     </ThemeProvider>
   );
 }

reflex/.templates/web/utils/state.js

@@ -227,8 +227,8 @@ export const applyEvent = async (event, socket) => {
       a.href = eval?.(
         event.payload.url.replace(
           "getBackendURL(env.UPLOAD)",
-          `"${getBackendURL(env.UPLOAD)}"`
-        )
+          `"${getBackendURL(env.UPLOAD)}"`,
+        ),
       );
     }
     a.download = event.payload.filename;
@@ -341,7 +341,7 @@ export const applyRestEvent = async (event, socket) => {
       event.payload.files,
       event.payload.upload_id,
       event.payload.on_upload_progress,
-      socket
+      socket,
     );
     return false;
   }
@@ -408,7 +408,7 @@ export const connect = async (
   dispatch,
   transports,
   setConnectErrors,
-  client_storage = {}
+  client_storage = {},
 ) => {
   // Get backend URL object from the endpoint.
   const endpoint = getBackendURL(EVENTURL);
@@ -499,7 +499,7 @@ export const uploadFiles = async (
   files,
   upload_id,
   on_upload_progress,
-  socket
+  socket,
 ) => {
   // return if there's no file to upload
   if (files === undefined || files.length === 0) {
@@ -604,7 +604,7 @@ export const Event = (
   name,
   payload = {},
   event_actions = {},
-  handler = null
+  handler = null,
 ) => {
   return { name, payload, handler, event_actions };
 };
@@ -631,7 +631,7 @@ export const hydrateClientStorage = (client_storage) => {
     for (const state_key in client_storage.local_storage) {
       const options = client_storage.local_storage[state_key];
       const local_storage_value = localStorage.getItem(
-        options.name || state_key
+        options.name || state_key,
       );
       if (local_storage_value !== null) {
         client_storage_values[state_key] = local_storage_value;
@@ -642,7 +642,7 @@ export const hydrateClientStorage = (client_storage) => {
     for (const state_key in client_storage.session_storage) {
       const session_options = client_storage.session_storage[state_key];
       const session_storage_value = sessionStorage.getItem(
-        session_options.name || state_key
+        session_options.name || state_key,
       );
       if (session_storage_value != null) {
         client_storage_values[state_key] = session_storage_value;
@@ -667,7 +667,7 @@ export const hydrateClientStorage = (client_storage) => {
 const applyClientStorageDelta = (client_storage, delta) => {
   // find the main state and check for is_hydrated
   const unqualified_states = Object.keys(delta).filter(
-    (key) => key.split(".").length === 1
+    (key) => key.split(".").length === 1,
   );
   if (unqualified_states.length === 1) {
     const main_state = delta[unqualified_states[0]];
@@ -701,7 +701,7 @@ const applyClientStorageDelta = (client_storage, delta) => {
         const session_options = client_storage.session_storage[state_key];
         sessionStorage.setItem(
           session_options.name || state_key,
-          delta[substate][key]
+          delta[substate][key],
         );
       }
     }
@@ -721,7 +721,7 @@ const applyClientStorageDelta = (client_storage, delta) => {
 export const useEventLoop = (
   dispatch,
   initial_events = () => [],
-  client_storage = {}
+  client_storage = {},
 ) => {
   const socket = useRef(null);
   const router = useRouter();
@@ -735,7 +735,7 @@ export const useEventLoop = (
 
     event_actions = events.reduce(
       (acc, e) => ({ ...acc, ...e.event_actions }),
-      event_actions ?? {}
+      event_actions ?? {},
     );
 
     const _e = args.filter((o) => o?.preventDefault !== undefined)[0];
@@ -763,7 +763,7 @@ export const useEventLoop = (
       debounce(
         combined_name,
         () => queueEvents(events, socket),
-        event_actions.debounce
+        event_actions.debounce,
       );
     } else {
       queueEvents(events, socket);
@@ -782,7 +782,7 @@ export const useEventLoop = (
             query,
             asPath,
           }))(router),
-        }))
+        })),
       );
       sentHydrate.current = true;
     }
@@ -817,13 +817,9 @@ export const useEventLoop = (
     };
   }, []);
 
-  // Main event loop.
+  // Handle socket connect/disconnect.
   useEffect(() => {
-    // Skip if the router is not ready.
-    if (!router.isReady) {
-      return;
-    }
-    // only use websockets if state is present
+    // only use websockets if state is present and backend is not disabled (reflex cloud).
     if (Object.keys(initialState).length > 1 && !isBackendDisabled()) {
       // Initialize the websocket connection.
       if (!socket.current) {
@@ -832,16 +828,31 @@ export const useEventLoop = (
           dispatch,
           ["websocket"],
           setConnectErrors,
-          client_storage
+          client_storage,
         );
       }
-      (async () => {
-        // Process all outstanding events.
-        while (event_queue.length > 0 && !event_processing) {
-          await processEvent(socket.current);
-        }
-      })();
     }
+
+    // Cleanup function.
+    return () => {
+      if (socket.current) {
+        socket.current.disconnect();
+      }
+    };
+  }, []);
+
+  // Main event loop.
+  useEffect(() => {
+    // Skip if the router is not ready.
+    if (!router.isReady || isBackendDisabled()) {
+      return;
+    }
+    (async () => {
+      // Process all outstanding events.
+      while (event_queue.length > 0 && !event_processing) {
+        await processEvent(socket.current);
+      }
+    })();
   });
 
   // localStorage event handling
@@ -865,7 +876,7 @@ export const useEventLoop = (
         vars[storage_to_state_map[e.key]] = e.newValue;
         const event = Event(
           `${state_name}.reflex___state____update_vars_internal_state.update_vars_internal`,
-          { vars: vars }
+          { vars: vars },
         );
         addEvents([event], e);
       }
@@ -958,7 +969,7 @@ export const getRefValues = (refs) => {
   return refs.map((ref) =>
     ref.current
       ? ref.current.value || ref.current.getAttribute("aria-valuenow")
-      : null
+      : null,
   );
 };
 

reflex/app.py

@@ -54,6 +54,7 @@ from reflex.compiler.compiler import ExecutorSafeFunctions, compile_theme
 from reflex.components.base.app_wrap import AppWrap
 from reflex.components.base.error_boundary import ErrorBoundary
 from reflex.components.base.fragment import Fragment
+from reflex.components.base.strict_mode import StrictMode
 from reflex.components.component import (
     Component,
     ComponentStyle,
@@ -956,6 +957,12 @@ class App(MiddlewareMixin, LifespanMixin):
             # If a theme component was provided, wrap the app with it
             app_wrappers[(20, "Theme")] = self.theme
 
+        # Get the env mode.
+        config = get_config()
+
+        if config.react_strict_mode:
+            app_wrappers[(200, "StrictMode")] = StrictMode.create()
+
         should_compile = self._should_compile()
 
         if not should_compile:
@@ -1001,9 +1008,6 @@ class App(MiddlewareMixin, LifespanMixin):
 
         progress.advance(task)
 
-        # Get the env mode.
-        config = get_config()
-
         # Store the compile results.
         compile_results = []
 

reflex/components/base/strict_mode.py

@@ -0,0 +1,10 @@
+"""Module for the StrictMode component."""
+
+from reflex.components.component import Component
+
+
+class StrictMode(Component):
+    """A React strict mode component to enable strict mode for its children."""
+
+    library = "react"
+    tag = "StrictMode"

reflex/components/base/strict_mode.pyi

@@ -0,0 +1,57 @@
+"""Stub file for reflex/components/base/strict_mode.py"""
+
+# ------------------- DO NOT EDIT ----------------------
+# This file was generated by `reflex/utils/pyi_generator.py`!
+# ------------------------------------------------------
+from typing import Any, Dict, Optional, Union, overload
+
+from reflex.components.component import Component
+from reflex.event import BASE_STATE, EventType
+from reflex.style import Style
+from reflex.vars.base import Var
+
+class StrictMode(Component):
+    @overload
+    @classmethod
+    def create(  # type: ignore
+        cls,
+        *children,
+        style: Optional[Style] = None,
+        key: Optional[Any] = None,
+        id: Optional[Any] = None,
+        class_name: Optional[Any] = None,
+        autofocus: Optional[bool] = None,
+        custom_attrs: Optional[Dict[str, Union[Var, Any]]] = None,
+        on_blur: Optional[EventType[[], BASE_STATE]] = None,
+        on_click: Optional[EventType[[], BASE_STATE]] = None,
+        on_context_menu: Optional[EventType[[], BASE_STATE]] = None,
+        on_double_click: Optional[EventType[[], BASE_STATE]] = None,
+        on_focus: Optional[EventType[[], BASE_STATE]] = None,
+        on_mount: Optional[EventType[[], BASE_STATE]] = None,
+        on_mouse_down: Optional[EventType[[], BASE_STATE]] = None,
+        on_mouse_enter: Optional[EventType[[], BASE_STATE]] = None,
+        on_mouse_leave: Optional[EventType[[], BASE_STATE]] = None,
+        on_mouse_move: Optional[EventType[[], BASE_STATE]] = None,
+        on_mouse_out: Optional[EventType[[], BASE_STATE]] = None,
+        on_mouse_over: Optional[EventType[[], BASE_STATE]] = None,
+        on_mouse_up: Optional[EventType[[], BASE_STATE]] = None,
+        on_scroll: Optional[EventType[[], BASE_STATE]] = None,
+        on_unmount: Optional[EventType[[], BASE_STATE]] = None,
+        **props,
+    ) -> "StrictMode":
+        """Create the component.
+
+        Args:
+            *children: The children of the component.
+            style: The style of the component.
+            key: A unique key for the component.
+            id: The id for the component.
+            class_name: The class name for the component.
+            autofocus: Whether the component should take the focus once the page is loaded
+            custom_attrs: custom attribute
+            **props: The props of the component.
+
+        Returns:
+            The component.
+        """
+        ...

reflex/utils/prerequisites.py

@@ -912,7 +912,6 @@ def _update_next_config(
     next_config = {
         "basePath": config.frontend_path or "",
         "compress": config.next_compression,
-        "reactStrictMode": config.react_strict_mode,
         "trailingSlash": True,
         "staticPageGenerationTimeout": config.static_page_generation_timeout,
     }

tests/units/test_app.py

@@ -1274,12 +1274,23 @@ def compilable_app(tmp_path) -> Generator[tuple[App, Path], None, None]:
         yield app, web_dir
 
 
-def test_app_wrap_compile_theme(compilable_app: tuple[App, Path]):
+@pytest.mark.parametrize(
+    "react_strict_mode",
+    [True, False],
+)
+def test_app_wrap_compile_theme(
+    react_strict_mode: bool, compilable_app: tuple[App, Path], mocker
+):
     """Test that the radix theme component wraps the app.
 
     Args:
+        react_strict_mode: Whether to use React Strict Mode.
         compilable_app: compilable_app fixture.
+        mocker: pytest mocker object.
     """
+    conf = rx.Config(app_name="testing", react_strict_mode=react_strict_mode)
+    mocker.patch("reflex.config._get_config", return_value=conf)
+
     app, web_dir = compilable_app
     app.theme = rx.theme(accent_color="plum")
     app._compile()
@@ -1290,24 +1301,37 @@ def test_app_wrap_compile_theme(compilable_app: tuple[App, Path]):
     assert (
         "function AppWrap({children}) {"
         "return ("
-        "<RadixThemesColorModeProvider>"
+        + ("<StrictMode>" if react_strict_mode else "")
+        + "<RadixThemesColorModeProvider>"
         "<RadixThemesTheme accentColor={\"plum\"} css={{...theme.styles.global[':root'], ...theme.styles.global.body}}>"
         "<Fragment>"
         "{children}"
         "</Fragment>"
         "</RadixThemesTheme>"
         "</RadixThemesColorModeProvider>"
-        ")"
+        + ("</StrictMode>" if react_strict_mode else "")
+        + ")"
         "}"
     ) in "".join(app_js_lines)
 
 
-def test_app_wrap_priority(compilable_app: tuple[App, Path]):
+@pytest.mark.parametrize(
+    "react_strict_mode",
+    [True, False],
+)
+def test_app_wrap_priority(
+    react_strict_mode: bool, compilable_app: tuple[App, Path], mocker
+):
     """Test that the app wrap components are wrapped in the correct order.
 
     Args:
+        react_strict_mode: Whether to use React Strict Mode.
         compilable_app: compilable_app fixture.
+        mocker: pytest mocker object.
     """
+    conf = rx.Config(app_name="testing", react_strict_mode=react_strict_mode)
+    mocker.patch("reflex.config._get_config", return_value=conf)
+
     app, web_dir = compilable_app
 
     class Fragment1(Component):
@@ -1339,8 +1363,7 @@ def test_app_wrap_priority(compilable_app: tuple[App, Path]):
     ]
     assert (
         "function AppWrap({children}) {"
-        "return ("
-        "<RadixThemesBox>"
+        "return (" + ("<StrictMode>" if react_strict_mode else "") + "<RadixThemesBox>"
         '<RadixThemesText as={"p"}>'
         "<RadixThemesColorModeProvider>"
         "<Fragment2>"
@@ -1350,8 +1373,7 @@ def test_app_wrap_priority(compilable_app: tuple[App, Path]):
         "</Fragment2>"
         "</RadixThemesColorModeProvider>"
         "</RadixThemesText>"
-        "</RadixThemesBox>"
-        ")"
+        "</RadixThemesBox>" + ("</StrictMode>" if react_strict_mode else "") + ")"
         "}"
     ) in "".join(app_js_lines)
 

tests/units/test_prerequisites.py

@@ -32,7 +32,7 @@ runner = CliRunner()
                 app_name="test",
             ),
             False,
-            'module.exports = {basePath: "", compress: true, reactStrictMode: true, trailingSlash: true, staticPageGenerationTimeout: 60};',
+            'module.exports = {basePath: "", compress: true, trailingSlash: true, staticPageGenerationTimeout: 60};',
         ),
         (
             Config(
@@ -40,7 +40,7 @@ runner = CliRunner()
                 static_page_generation_timeout=30,
             ),
             False,
-            'module.exports = {basePath: "", compress: true, reactStrictMode: true, trailingSlash: true, staticPageGenerationTimeout: 30};',
+            'module.exports = {basePath: "", compress: true, trailingSlash: true, staticPageGenerationTimeout: 30};',
         ),
         (
             Config(
@@ -48,7 +48,7 @@ runner = CliRunner()
                 next_compression=False,
             ),
             False,
-            'module.exports = {basePath: "", compress: false, reactStrictMode: true, trailingSlash: true, staticPageGenerationTimeout: 60};',
+            'module.exports = {basePath: "", compress: false, trailingSlash: true, staticPageGenerationTimeout: 60};',
         ),
         (
             Config(
@@ -56,7 +56,7 @@ runner = CliRunner()
                 frontend_path="/test",
             ),
             False,
-            'module.exports = {basePath: "/test", compress: true, reactStrictMode: true, trailingSlash: true, staticPageGenerationTimeout: 60};',
+            'module.exports = {basePath: "/test", compress: true, trailingSlash: true, staticPageGenerationTimeout: 60};',
         ),
         (
             Config(
@@ -65,14 +65,14 @@ runner = CliRunner()
                 next_compression=False,
             ),
             False,
-            'module.exports = {basePath: "/test", compress: false, reactStrictMode: true, trailingSlash: true, staticPageGenerationTimeout: 60};',
+            'module.exports = {basePath: "/test", compress: false, trailingSlash: true, staticPageGenerationTimeout: 60};',
         ),
         (
             Config(
                 app_name="test",
             ),
             True,
-            'module.exports = {basePath: "", compress: true, reactStrictMode: true, trailingSlash: true, staticPageGenerationTimeout: 60, output: "export", distDir: "_static"};',
+            'module.exports = {basePath: "", compress: true, trailingSlash: true, staticPageGenerationTimeout: 60, output: "export", distDir: "_static"};',
         ),
     ],
 )