[FIX] OWFile: Show error msg when file doesn't exists

Orange/widgets/data/owfile.py

@@ -117,6 +117,9 @@ class Warning(widget.OWWidget.Warning):
         file_too_big = widget.Msg("The file is too large to load automatically."
                                   " Press Reload to load.")
 
+    class Error(widget.OWWidget.Error):
+        file_not_found = widget.Msg("File not found.")
+
     def __init__(self):
         super().__init__()
         RecentPathsWComboMixin.__init__(self)
@@ -219,7 +222,8 @@ def __init__(self):
 
         if self.source == self.LOCAL_FILE:
             last_path = self.last_path()
-            if last_path and os.path.getsize(last_path) > self.SIZE_LIMIT:
+            if last_path and os.path.exists(last_path) and \
+                    os.path.getsize(last_path) > self.SIZE_LIMIT:
                 self.Warning.file_too_big()
                 return
 
@@ -271,7 +275,13 @@ def load_data(self):
         self.closeContext()
         self.domain_editor.set_domain(None)
         self.apply_button.setEnabled(False)
-        self.Warning.file_too_big.clear()
+        self.clear_messages()
+        self.set_file_list()
+        if self.last_path() and not os.path.exists(self.last_path()):
+            self.Error.file_not_found()
+            self.send("Data", None)
+            self.info.setText("No data.")
+            return
 
         error = None
         try:

Orange/widgets/data/tests/test_owfile.py

@@ -1,13 +1,16 @@
 # Test methods with long descriptive names can omit docstrings
 # pylint: disable=missing-docstring
-from os import path
+from os import path, remove
 from unittest.mock import Mock
 
+import numpy as np
+
 from AnyQt.QtCore import QMimeData, QPoint, Qt, QUrl
 from AnyQt.QtGui import QDragEnterEvent, QDropEvent
 
 import Orange
-from Orange.data import FileFormat, dataset_dirs, StringVariable
+from Orange.data import FileFormat, dataset_dirs, StringVariable, Table, \
+    Domain, DiscreteVariable
 from Orange.widgets.data.owfile import OWFile
 from Orange.widgets.tests.base import WidgetTest
 
@@ -99,3 +102,28 @@ def test_no_last_path(self):
             self.create_widget(OWFile, stored_settings={"recent_paths": []})
         # Doesn't crash and contains a single item, (none).
         self.assertEqual(self.widget.file_combo.count(), 1)
+
+    def test_file_not_found(self):
+        # Create a dummy file
+        file_name = "test_owfile_data.tab"
+        domainA = Domain([DiscreteVariable("d1", values=("a", "b"))],
+                         DiscreteVariable("c1", values=("aaa", "bbb")))
+        dataA = Table(domainA, np.array([[0], [1], [0], [np.nan]]),
+                      np.array([0, 1, 0, 1]))
+        dataA.save(file_name)
+
+        # Open the file with the widget
+        self.open_dataset(file_name)
+        self.assertEqual(self.get_output("Data").domain, dataA.domain)
+
+        # Delete the file and try to reload it
+        remove(file_name)
+        self.widget.load_data()
+        self.assertEqual(file_name, path.basename(self.widget.last_path()))
+        self.assertTrue(self.widget.Error.file_not_found.is_shown())
+        self.assertIsNone(self.get_output("Data"))
+        self.assertEqual(self.widget.info.text(), "No data.")
+
+        # Open a sample dataset
+        self.open_dataset("iris")
+        self.assertFalse(self.widget.Error.file_not_found.is_shown())

Orange/widgets/utils/filedialogs.py

@@ -1,6 +1,7 @@
 import os
 
-from AnyQt.QtCore import QFileInfo
+from AnyQt.QtCore import QFileInfo, Qt
+from AnyQt.QtGui import QBrush
 from AnyQt.QtWidgets import \
     QMessageBox, QFileDialog, QFileIconProvider, QComboBox
 
@@ -281,6 +282,8 @@ def _relocate_recent_files(self):
                 rec.append(
                     RecentPath.create(recent.search(search_paths), search_paths, **kwargs)
                 )
+            else:
+                rec.append(recent)
         # change the list in-place for the case the widgets wraps this list
         # in some model (untested!)
         self.recent_paths[:] = rec
@@ -351,6 +354,9 @@ def set_file_list(self):
             for i, recent in enumerate(self.recent_paths):
                 self.file_combo.addItem(recent.basename)
                 self.file_combo.model().item(i).setToolTip(recent.abspath)
+                if not os.path.exists(recent.abspath):
+                    self.file_combo.setItemData(i, QBrush(Qt.red),
+                                                Qt.TextColorRole)
 
     def workflowEnvChanged(self, key, value, oldvalue):
         super().workflowEnvChanged(key, value, oldvalue)