fix bun path handling and add a test (#4785)

* fix bun path handling and add a test

* fix flags

* fix tests

* fix unit tests and mock object

* fix units test again

* revert some changes for now

* remove unused test

Author: Lendemor

reflex/reflex.py

@@ -145,10 +145,7 @@ def _run(
     exec.output_system_info()
 
     # If no --frontend-only and no --backend-only, then turn on frontend and backend both
-    if not frontend and not backend:
-        frontend = True
-        backend = True
-
+    frontend, backend = prerequisites.check_running_mode(frontend, backend)
     if not frontend and backend:
         _skip_compile()
 
@@ -306,10 +303,18 @@ def export(
         True, "--no-zip", help="Disable zip for backend and frontend exports."
     ),
     frontend: bool = typer.Option(
-        True, "--backend-only", help="Export only backend.", show_default=False
+        False,
+        "--frontend-only",
+        help="Export only frontend.",
+        show_default=False,
+        envvar=environment.REFLEX_FRONTEND_ONLY.name,
     ),
     backend: bool = typer.Option(
-        True, "--frontend-only", help="Export only frontend.", show_default=False
+        False,
+        "--backend-only",
+        help="Export only backend.",
+        show_default=False,
+        envvar=environment.REFLEX_BACKEND_ONLY.name,
     ),
     zip_dest_dir: str = typer.Option(
         str(Path.cwd()),
@@ -332,7 +337,9 @@ def export(
     from reflex.utils import export as export_utils
     from reflex.utils import prerequisites
 
-    if prerequisites.needs_reinit(frontend=True):
+    frontend, backend = prerequisites.check_running_mode(frontend, backend)
+
+    if prerequisites.needs_reinit(frontend=frontend or not backend):
         _init(name=config.app_name, loglevel=loglevel)
 
     if frontend and not config.show_built_with_reflex:

reflex/utils/path_ops.py

@@ -247,6 +247,22 @@ def find_replace(directory: str | Path, find: str, replace: str):
             filepath.write_text(text, encoding="utf-8")
 
 
+def samefile(file1: Path, file2: Path) -> bool:
+    """Check if two files are the same.
+
+    Args:
+        file1: The first file.
+        file2: The second file.
+
+    Returns:
+        Whether the files are the same. If either file does not exist, returns False.
+    """
+    if file1.exists() and file2.exists():
+        return file1.samefile(file2)
+
+    return False
+
+
 def update_directory_tree(src: Path, dest: Path):
     """Recursively copies a directory tree from src to dest.
     Only copies files if the destination file is missing or modified earlier than the source file.

reflex/utils/prerequisites.py

@@ -1225,6 +1225,21 @@ def install_frontend_packages(packages: set[str], config: Config):
         )
 
 
+def check_running_mode(frontend: bool, backend: bool) -> tuple[bool, bool]:
+    """Check if the app is running in frontend or backend mode.
+
+    Args:
+        frontend: Whether to run the frontend of the app.
+        backend: Whether to run the backend of the app.
+
+    Returns:
+        The running modes.
+    """
+    if not frontend and not backend:
+        return True, True
+    return frontend, backend
+
+
 def needs_reinit(frontend: bool = True) -> bool:
     """Check if an app needs to be reinitialized.
 
@@ -1293,10 +1308,13 @@ def validate_bun():
     """
     bun_path = path_ops.get_bun_path()
 
-    if bun_path and not bun_path.samefile(constants.Bun.DEFAULT_PATH):
+    if bun_path is None:
+        return
+
+    if not path_ops.samefile(bun_path, constants.Bun.DEFAULT_PATH):
         console.info(f"Using custom Bun path: {bun_path}")
         bun_version = get_bun_version()
-        if not bun_version:
+        if bun_version is None:
             console.error(
                 "Failed to obtain bun version. Make sure the specified bun path in your config is correct."
             )

tests/units/utils/test_utils.py

@@ -115,21 +115,33 @@ def test_typehint_issubclass(subclass, superclass, expected):
     assert types.typehint_issubclass(subclass, superclass) == expected
 
 
-def test_validate_invalid_bun_path(mocker):
+def test_validate_none_bun_path(mocker):
+    """Test that an error is thrown when a bun path is not specified.
+
+    Args:
+        mocker: Pytest mocker object.
+    """
+    mocker.patch("reflex.utils.path_ops.get_bun_path", return_value=None)
+    # with pytest.raises(typer.Exit):
+    prerequisites.validate_bun()
+
+
+def test_validate_invalid_bun_path(
+    mocker,
+):
     """Test that an error is thrown when a custom specified bun path is not valid
     or does not exist.
 
     Args:
         mocker: Pytest mocker object.
     """
     mock_path = mocker.Mock()
-    mock_path.samefile.return_value = False
     mocker.patch("reflex.utils.path_ops.get_bun_path", return_value=mock_path)
+    mocker.patch("reflex.utils.path_ops.samefile", return_value=False)
     mocker.patch("reflex.utils.prerequisites.get_bun_version", return_value=None)
 
     with pytest.raises(typer.Exit):
         prerequisites.validate_bun()
-    mock_path.samefile.assert_called_once()
 
 
 def test_validate_bun_path_incompatible_version(mocker):
@@ -141,6 +153,7 @@ def test_validate_bun_path_incompatible_version(mocker):
     mock_path = mocker.Mock()
     mock_path.samefile.return_value = False
     mocker.patch("reflex.utils.path_ops.get_bun_path", return_value=mock_path)
+    mocker.patch("reflex.utils.path_ops.samefile", return_value=False)
     mocker.patch(
         "reflex.utils.prerequisites.get_bun_version",
         return_value=version.parse("0.6.5"),