get this working with relative imports and hot reload

reflex/app_module_for_backend.py

@@ -7,14 +7,13 @@ from concurrent.futures import ThreadPoolExecutor
 from reflex import constants
 from reflex.utils import telemetry
 from reflex.utils.exec import is_prod_mode
-from reflex.utils.prerequisites import get_app
+from reflex.utils.prerequisites import get_and_validate_app
 
 if constants.CompileVars.APP != "app":
     raise AssertionError("unexpected variable name for 'app'")
 
 telemetry.send("compile")
-app_module = get_app(reload=False)
+app, app_module = get_and_validate_app(reload=False)
-app = getattr(app_module, constants.CompileVars.APP)
 # For py3.9 compatibility when redis is used, we MUST add any decorator pages
 # before compiling the app in a thread to avoid event loop error (REF-2172).
 app._apply_decorated_pages()
@@ -30,7 +29,7 @@ if is_prod_mode():
 # ensure only "app" is exposed.
 del app_module
 del compile_future
-del get_app
+del get_and_validate_app
 del is_prod_mode
 del telemetry
 del constants

reflex/config.py

@@ -730,24 +730,36 @@ class Config(Base):
                 "REDIS_URL is required when using the redis state manager."
             )
 
+    @staticmethod
+    def _load_via_spec(path: str) -> ModuleType:
+        """Load a module dynamically using its file path.
+
+        Args:
+            path: The path to the module.
+
+        Returns:
+            The loaded module.
+        """
+        module_name = Path(path).stem
+        module_path = Path(path).resolve()
+        sys.path.insert(0, str(module_path.parent.parent))
+        spec = importlib.util.spec_from_file_location(module_name, path)
+        module = importlib.util.module_from_spec(spec)
+        # Set the package name to the parent directory of the module (for relative imports)
+        module.__package__ = module_path.parent.name
+        spec.loader.exec_module(module)
+        return module
+
     @property
     def app_module(self) -> ModuleType | None:
-        """Get the app module.
+        """Return the app module if `app_module_path` is set.
 
         Returns:
             The app module.
         """
-
+        return (
-        def load_via_spec(path):
+            self._load_via_spec(self.app_module_path) if self.app_module_path else None
-            module_name = Path(path).stem
+        )
-            spec = importlib.util.spec_from_file_location(module_name, path)
-            module = importlib.util.module_from_spec(spec)
-            spec.loader.exec_module(module)
-            return module
-
-        if self.app_module_path:
-            return load_via_spec(self.app_module_path)
-        return None
 
     @property
     def module(self) -> str:

reflex/state.py

@@ -1759,7 +1759,7 @@ class BaseState(Base, ABC, extra=pydantic.Extra.allow):
         except Exception as ex:
             state._clean()
 
-            app_instance = getattr(prerequisites.get_app(), constants.CompileVars.APP)
+            app_instance = prerequisites.get_and_validate_app().app
 
             event_specs = app_instance.backend_exception_handler(ex)
 
@@ -1871,7 +1871,7 @@ class BaseState(Base, ABC, extra=pydantic.Extra.allow):
         except Exception as ex:
             telemetry.send_error(ex, context="backend")
 
-            app_instance = getattr(prerequisites.get_app(), constants.CompileVars.APP)
+            app_instance = prerequisites.get_and_validate_app().app
 
             event_specs = app_instance.backend_exception_handler(ex)
 
@@ -2383,7 +2383,7 @@ class FrontendEventExceptionState(State):
             component_stack: The stack trace of the component where the exception occurred.
 
         """
-        app_instance = getattr(prerequisites.get_app(), constants.CompileVars.APP)
+        app_instance, _ = prerequisites.get_and_validate_app()
         app_instance.frontend_exception_handler(Exception(stack))
 
 
@@ -2422,7 +2422,7 @@ class OnLoadInternalState(State):
             The list of events to queue for on load handling.
         """
         # Do not app._compile()!  It should be already compiled by now.
-        app = getattr(prerequisites.get_app(), constants.CompileVars.APP)
+        app = prerequisites.get_and_validate_app().app
         load_events = app.get_load_events(self.router.page.path)
         if not load_events:
             self.is_hydrated = True
@@ -2589,7 +2589,7 @@ class StateProxy(wrapt.ObjectProxy):
         """
         super().__init__(state_instance)
         # compile is not relevant to backend logic
-        self._self_app = getattr(prerequisites.get_app(), constants.CompileVars.APP)
+        self._self_app = prerequisites.get_and_validate_app().app
         self._self_substate_path = tuple(state_instance.get_full_name().split("."))
         self._self_actx = None
         self._self_mutable = False
@@ -3682,7 +3682,7 @@ def get_state_manager() -> StateManager:
     Returns:
         The state manager.
     """
-    app = getattr(prerequisites.get_app(), constants.CompileVars.APP)
+    app = prerequisites.get_and_validate_app().app
     return app.state_manager
 
 

reflex/utils/exec.py

@@ -240,6 +240,19 @@ def run_backend(
         run_uvicorn_backend(host, port, loglevel)
 
 
+def get_reload_dirs() -> list[str]:
+    """Get the reload directories for the backend.
+
+    Returns:
+        The reload directories for the backend.
+    """
+    config = get_config()
+    reload_dirs = [config.app_name]
+    if app_module_path := config.app_module_path:
+        reload_dirs.append(str(Path(app_module_path).resolve().parent.parent))
+    return reload_dirs
+
+
 def run_uvicorn_backend(host, port, loglevel: LogLevel):
     """Run the backend in development mode using Uvicorn.
 
@@ -256,7 +269,7 @@ def run_uvicorn_backend(host, port, loglevel: LogLevel):
         port=port,
         log_level=loglevel.value,
         reload=True,
-        reload_dirs=[get_config().app_name],
+        reload_dirs=get_reload_dirs(),
     )
 
 
@@ -281,7 +294,7 @@ def run_granian_backend(host, port, loglevel: LogLevel):
             interface=Interfaces.ASGI,
             log_level=LogLevels(loglevel.value),
             reload=True,
-            reload_paths=[Path(get_config().app_name)],
+            reload_paths=get_reload_dirs(),
             reload_ignore_dirs=[".web"],
         ).serve()
     except ImportError:

reflex/utils/prerequisites.py

@@ -17,11 +17,13 @@ import stat
 import sys
 import tempfile
 import time
+import typing
 import zipfile
 from datetime import datetime
 from pathlib import Path
 from types import ModuleType
 from typing import Callable, List, Optional
+from collections import namedtuple
 
 import httpx
 import typer
@@ -42,9 +44,12 @@ from reflex.utils.exceptions import (
 from reflex.utils.format import format_library_name
 from reflex.utils.registry import _get_npm_registry
 
+if typing.TYPE_CHECKING:
+    from reflex.app import App
+
 CURRENTLY_INSTALLING_NODE = False
 
-
+AppInfo = namedtuple("AppInfo", ["app", "module"])
 @dataclasses.dataclass(frozen=True)
 class Template:
     """A template for a Reflex app."""
@@ -296,7 +301,6 @@ def get_app(reload: bool = False) -> ModuleType:
             if not config.app_module
             else config.app_module
         )
-
         if reload:
             from reflex.state import reload_state_module
 
@@ -312,19 +316,24 @@ def get_app(reload: bool = False) -> ModuleType:
         raise
 
 
-def get_and_validate_app(reload: bool = False):
+def get_and_validate_app(reload: bool = False) -> AppInfo:
-    """Get the app module based on the default config and validate it.
+    """Get the app instance based on the default config and validate it.
 
     Args:
         reload: Re-import the app module from disk
+
+    Returns:
+        The app instance and the app module.
     """
     from reflex.app import App
 
     app_module = get_app(reload=reload)
     app = getattr(app_module, constants.CompileVars.APP)
     if not isinstance(app, App):
-        raise RuntimeError("The app object in rxconfig must be an instance of rx.App.")
+        raise RuntimeError(
-    return app
+            "The app instance in the specified app_module_path in rxconfig must be an instance of rx.App."
+        )
+    return AppInfo(app=app, module=app_module)
 
 
 def get_compiled_app(reload: bool = False, export: bool = False) -> ModuleType:
@@ -337,8 +346,7 @@ def get_compiled_app(reload: bool = False, export: bool = False) -> ModuleType:
     Returns:
         The compiled app based on the default config.
     """
-    app_module = get_app(reload=reload)
+    app, app_module = get_and_validate_app(reload=reload)
-    app = getattr(app_module, constants.CompileVars.APP)
     # For py3.9 compatibility when redis is used, we MUST add any decorator pages
     # before compiling the app in a thread to avoid event loop error (REF-2172).
     app._apply_decorated_pages()