fix(pdf_viewer): connect document status once instead of disconnecting unconnected slots

bec_widgets/widgets/utility/pdf_viewer/pdf_viewer.py

@@ -56,6 +56,7 @@ class PdfViewerWidget(BECWidget, QWidget):
 
         # Create the PDF document and view first
         self._pdf_document = QPdfDocument(self)
+        self._pdf_document.statusChanged.connect(self._on_document_status_changed)
         self.pdf_view = QPdfView()
         self.pdf_view.setZoomMode(QPdfView.ZoomMode.FitToWidth)
 
@@ -328,15 +329,6 @@ class PdfViewerWidget(BECWidget, QWidget):
 
         self._current_file_path = file_path
 
-        # Disconnect any existing signal connections
-        try:
-            self._pdf_document.statusChanged.disconnect(self._on_document_status_changed)
-        except (TypeError, RuntimeError):
-            pass
-
-        # Connect to statusChanged signal to handle when document is ready
-        self._pdf_document.statusChanged.connect(self._on_document_status_changed)
-
         # Load the document
         self._pdf_document.load(file_path)
 
@@ -544,10 +536,12 @@ class PdfViewerWidget(BECWidget, QWidget):
 
     def cleanup(self):
         """Handle widget close event to prevent segfaults."""
-        if hasattr(self, "_pdf_document") and self._pdf_document:
-            self._pdf_document.statusChanged.disconnect()
+        # Cleanup can run twice (explicit call, then close); disconnect only once.
+        if getattr(self, "_pdf_document", None) is not None:
+            self._pdf_document.statusChanged.disconnect(self._on_document_status_changed)
             empty_doc = QPdfDocument(self)
             self.pdf_view.setDocument(empty_doc)
+            self._pdf_document = None
 
         if hasattr(self, "toolbar"):
             self.toolbar.cleanup()

tests/unit_tests/test_pdf_viewer.py

@@ -1,3 +1,5 @@
+import warnings
+
 import pytest
 from qtpy.QtPdf import QPdfDocument
 from qtpy.QtPdfWidgets import QPdfView
@@ -227,6 +229,26 @@ def test_load_pdf_file(qtbot, pdf_viewer_widget: PdfViewerWidget, temp_pdf_file,
     assert widget.current_file_path == temp_pdf_file
 
 
+def test_load_and_cleanup_do_not_warn_about_disconnect(
+    qtbot, mocked_client, temp_pdf_file, temp_pdf_file_2
+):
+    """Loading, reloading and (repeated) cleanup never disconnect a slot that is not connected."""
+    with warnings.catch_warnings(record=True) as caught:
+        warnings.simplefilter("always")
+        widget = PdfViewerWidget(client=mocked_client)
+        qtbot.addWidget(widget)
+        widget.load_pdf(temp_pdf_file)
+        widget.load_pdf(temp_pdf_file_2)
+        qtbot.wait(100)
+        widget.cleanup()
+        widget.cleanup()  # a repeated cleanup must not disconnect again
+        unloaded = PdfViewerWidget(client=mocked_client)
+        qtbot.addWidget(unloaded)
+        unloaded.cleanup()
+
+    assert [str(w.message) for w in caught if "Failed to disconnect" in str(w.message)] == []
+
+
 def test_load_invalid_pdf_file(qtbot, pdf_viewer_widget: PdfViewerWidget, tmpdir):
     """Test loading an invalid PDF file into the viewer."""
     widget = pdf_viewer_widget