add checks to _get_python_path()

Author: Mike Prosser

src/nipanel/_panel.py

@@ -37,7 +37,7 @@ def __init__(
             grpc_channel=grpc_channel,
         )
         self._panel_script_path = panel_script_path
-        python_path = str(Path(sys.executable).resolve())
+        python_path = self._get_python_path()
         self._panel_url = self._panel_client.start_panel(panel_id, panel_script_path, python_path)
 
     @property
@@ -49,3 +49,12 @@ def panel_script_path(self) -> str:
     def panel_url(self) -> str:
         """Read-only accessor for the panel URL."""
         return self._panel_url
+
+    def _get_python_path(self) -> str:
+        """Get the Python path for the panel."""
+        if getattr(sys, "frozen", False):
+            raise RuntimeError("Panel cannot be used in a frozen application (e.g., PyInstaller).")
+        python_path = str(Path(sys.executable).resolve())
+        if python_path is None or python_path == "":
+            raise RuntimeError("Python environment not found")
+        return python_path

tests/unit/test_streamlit_panel.py

@@ -350,6 +350,15 @@ def test___panel___panel_is_running_and_in_memory(
     assert is_panel_running(panel)
 
 
+def test___panel___python_path_is_in_venv(
+    fake_python_panel_service: FakePythonPanelService,
+    fake_panel_channel: grpc.Channel,
+) -> None:
+    StreamlitPanel("my_panel", "path/to/script", grpc_channel=fake_panel_channel)
+
+    assert ".venv" in fake_python_panel_service.servicer.python_path
+
+
 def is_panel_in_memory(panel: StreamlitPanel) -> bool:
     return panel.panel_id in panel._panel_client.enumerate_panels().keys()
 

tests/utils/_fake_python_panel_servicer.py

@@ -27,11 +27,13 @@ def __init__(self) -> None:
         self._panel_value_ids: dict[str, dict[str, Any]] = {}
         self._fail_next_start_panel = False
         self._notification_count: int = 0
+        self._python_path: str = ""
 
     def StartPanel(  # noqa: N802
         self, request: StartPanelRequest, context: Any
     ) -> StartPanelResponse:
         """Trivial implementation for testing."""
+        self._python_path = request.python_path
         if self._fail_next_start_panel:
             self._fail_next_start_panel = False
             context.abort(grpc.StatusCode.UNAVAILABLE, "Simulated failure")
@@ -81,6 +83,11 @@ def notification_count(self) -> int:
         """Get the number of notifications sent from SetValue."""
         return self._notification_count
 
+    @property
+    def python_path(self) -> str:
+        """Get the Python path used to start the panel."""
+        return self._python_path
+
     def _init_panel(self, panel_id: str) -> None:
         if panel_id not in self._panel_ids:
             self._panel_ids.append(panel_id)