Merge from 3.x: PR #3906

Fixes #3673

spyder/widgets/variableexplorer/collectionseditor.py

@@ -505,9 +505,12 @@ def createEditor(self, parent, option, index):
             return editor
         #---editor = TextEditor
         elif is_text_string(value) and len(value) > 40:
-            editor = TextEditor(value, key)
-            self.create_dialog(editor, dict(model=index.model(), editor=editor,
-                                            key=key, readonly=readonly))
+            te = TextEditor(None)
+            if te.setup_and_check(value):
+                editor = TextEditor(value, key)
+                self.create_dialog(editor, dict(model=index.model(),
+                                                editor=editor, key=key,
+                                                readonly=readonly))
             return None
         #---editor = QLineEdit
         elif is_editable_type(value):

spyder/widgets/variableexplorer/tests/test_texteditor.py

@@ -12,6 +12,7 @@
 import pytest
 
 # Local imports
+from spyder.py3compat import PY2
 from spyder.widgets.variableexplorer.texteditor import TextEditor
 
 @pytest.fixture
@@ -31,6 +32,16 @@ def test_texteditor(qtbot):
     dlg_text = texteditor.get_value()
     assert text == dlg_text
 
+def test_texteditor_setup_and_check():
+    if PY2:
+        import string
+        dig_its = string.digits;
+        translate_digits = string.maketrans(dig_its,len(dig_its)*' ')
+        editor = TextEditor(None)
+        assert not editor.setup_and_check(translate_digits)
+    else:
+        assert True
+
 
 if __name__ == "__main__":
     pytest.main()

spyder/widgets/variableexplorer/texteditor.py

@@ -89,6 +89,14 @@ def get_value(self):
         # already been destroyed, due to the Qt.WA_DeleteOnClose attribute
         return self.text
 
+    def setup_and_check(self, value):
+        """Verify if TextEditor is able to display strings passed to it."""
+        try:
+            to_text_string(value, 'utf8')
+            return True
+        except:
+            return False
+
 
 #==============================================================================
 # Tests