add: reflex init app name validator (#2336)

reflex/reflex.py

@@ -74,8 +74,8 @@ def _init(
     # Show system info
     exec.output_system_info()
 
-    # Get the app name.
-    app_name = prerequisites.get_default_app_name() if name is None else name
+    # Validate the app name.
+    app_name = prerequisites.validate_app_name(name)
     console.rule(f"[bold]Initializing {app_name}")
 
     prerequisites.check_latest_package_version(constants.Reflex.MODULE_NAME)

reflex/utils/prerequisites.py

@@ -215,19 +215,23 @@ def get_production_backend_url() -> str:
     )
 
 
-def get_default_app_name() -> str:
-    """Get the default app name.
+def validate_app_name(app_name: str | None = None) -> str:
+    """Validate the app name.
 
     The default app name is the name of the current directory.
 
+    Args:
+        app_name: the name passed by user during reflex init
+
     Returns:
-        The default app name.
+        The app name after validation.
 
     Raises:
-        Exit: if the app directory name is reflex.
+        Exit: if the app directory name is reflex or if the name is not standard for a python package name.
     """
-    app_name = os.getcwd().split(os.path.sep)[-1].replace("-", "_")
-
+    app_name = (
+        app_name if app_name else os.getcwd().split(os.path.sep)[-1].replace("-", "_")
+    )
     # Make sure the app is not named "reflex".
     if app_name == constants.Reflex.MODULE_NAME:
         console.error(
@@ -235,6 +239,13 @@ def get_default_app_name() -> str:
         )
         raise typer.Exit(1)
 
+    # Make sure the app name is standard for a python package name.
+    if not re.match(r"^[a-zA-Z][a-zA-Z0-9_]*$", app_name):
+        console.error(
+            "The app directory name must start with a letter and can contain letters, numbers, and underscores."
+        )
+        raise typer.Exit(1)
+
     return app_name
 
 

tests/utils/test_utils.py

@@ -306,8 +306,8 @@ def test_initialize_non_existent_gitignore(tmp_path, mocker, gitignore_exists):
     assert set(file_content) - expected == set()
 
 
-def test_app_default_name(tmp_path, mocker):
-    """Test that an error is raised if the app name is reflex.
+def test_validate_app_name(tmp_path, mocker):
+    """Test that an error is raised if the app name is reflex or if the name is not according to python package naming conventions.
 
     Args:
         tmp_path: Test working dir.
@@ -319,7 +319,10 @@ def test_app_default_name(tmp_path, mocker):
     mocker.patch("reflex.utils.prerequisites.os.getcwd", return_value=str(reflex))
 
     with pytest.raises(typer.Exit):
-        prerequisites.get_default_app_name()
+        prerequisites.validate_app_name()
+
+    with pytest.raises(typer.Exit):
+        prerequisites.validate_app_name(app_name="1_test")
 
 
 def test_node_install_windows(tmp_path, mocker):