FIX: Pick up changes to UI files when the main window is reloaded

pydm/display.py

@@ -116,6 +116,14 @@ def _load_ui_into_display(uifile, display):
     display.ui = display
 
 
+def clear_compiled_ui_file_cache() -> None:
+    """
+    Clears the cache of compiled ui files. Needed if changes to the underlying ui files have been made on disk and
+    need to be picked up, such as the user choosing to reload the display.
+    """
+    _compile_ui_file.cache_clear()
+
+
 def _load_compiled_ui_into_display(
     code_string: str, class_name: str, display: Display, macros: Optional[Dict[str, str]] = None
 ) -> None:

pydm/main_window.py

@@ -6,7 +6,7 @@
 from qtpy.QtGui import QKeySequence
 from .utilities import IconFont, find_file, establish_widget_connections, close_widget_connections
 from .pydm_ui import Ui_MainWindow
-from .display import Display, ScreenTarget, load_file
+from .display import Display, ScreenTarget, load_file, clear_compiled_ui_file_cache
 from .connection_inspector import ConnectionInspector
 from .about_pydm import AboutWindow
 from .show_macros import MacroWindow
@@ -442,6 +442,7 @@ def reload_display(self, checked):
         loaded_file = curr_display.loaded_file()
 
         self.statusBar().showMessage("Reloading '{0}'...".format(self.current_file()), 5000)
+        clear_compiled_ui_file_cache()
         new_widget = self.open(loaded_file, macros=macros, args=args)
         new_widget.previous_display = prev_display
         new_widget.next_display = next_display

pydm/tests/test_main_window.py

@@ -0,0 +1,30 @@
+import os
+
+from pydm import PyDMApplication
+from pydm.display import Display, clear_compiled_ui_file_cache
+from qtpy import uic
+from unittest.mock import MagicMock, patch
+
+# The path to the .ui file for creating a main window
+test_ui_path = os.path.join(os.path.dirname(os.path.realpath(__file__)), "test_data", "test.ui")
+
+
+@patch("qtpy.uic.compileUi", wraps=uic.compileUi)
+def test_reload_display(wrapped_compile_ui: MagicMock, qapp: PyDMApplication) -> None:
+    """Verify that when a user reloads a PyDM window the underling display's ui file is actually reloaded"""
+    clear_compiled_ui_file_cache()  # Ensure other tests have not already compiled our test file before we start
+
+    try:
+        display = Display(parent=None, ui_filename=test_ui_path)
+
+        qapp.make_main_window()
+        qapp.main_window.set_display_widget(display)
+
+        # When the display is first created and loaded the underlying ui file gets compiled
+        wrapped_compile_ui.assert_called_once()
+
+        # Reloading should force a re-compile of the ui file to ensure any changes are picked up
+        qapp.main_window.reload_display(True)
+        assert wrapped_compile_ui.call_count == 2
+    finally:
+        clear_compiled_ui_file_cache()