Manually check whether persistent_history_file is a directory

Author: kotfu

cmd2/cmd2.py

@@ -3469,15 +3469,18 @@ def _initialize_history(self, hist_file):
 
         # first we try and unpickle the history file
         history = History()
+        # on Windows, trying to open a directory throws a permission
+        # error, not a `IsADirectoryError`. So we'll check it ourselves.
+        if os.path.isdir(hist_file):
+            msg = "persistent history file '{}' is a directory"
+            self.perror(msg.format(hist_file))
+            return
+
         try:
             with open(hist_file, 'rb') as fobj:
                 history = pickle.load(fobj)
         except (FileNotFoundError, KeyError, EOFError):
             pass
-        except IsADirectoryError:
-            msg = "persistent history file '{}' is a directory"
-            self.perror(msg.format(hist_file))
-            return
         except OSError as ex:
             msg = "can not read persistent history file '{}': {}"
             self.perror(msg.format(hist_file, ex), traceback_war=False)

tests/test_history.py

@@ -459,18 +459,11 @@ def hist_file():
         pass
 
 def test_bad_history_file_path(capsys, request):
-    # can't use tempfile.TemporaryDirectory() as a context on Appveyor
-    # on windows. it causes a file locking issue which is reflected as
-    # a permission exception
-    test_dir = tempfile.mkdtemp()
-    # Create a new cmd2 app
-    cmd2.Cmd(persistent_history_file=test_dir)
-    _, err = capsys.readouterr()
-    assert 'is a directory' in err
-    try:
-        os.rmdir(test_dir)
-    except OSError:
-        pass
+    with tempfile.TemporaryDirectory() as test_dir:
+        # Create a new cmd2 app
+        cmd2.Cmd(persistent_history_file=test_dir)
+        _, err = capsys.readouterr()
+        assert 'is a directory' in err
 
 def test_history_file_conversion_no_truncate_on_init(hist_file, capsys):
     # test the code that converts a plain text history file to a pickle binary