# Buggy code
def get_dialog_directory(self, default=None):
    """
    Return the directory folder which a load/save dialog box should
    open into. In order of precedence this function will return:

    0) If not None, the value of default.
    1) The last location used by a load/save dialog.
    2) The directory containing the current file.
    3) The mode's reported workspace directory.
    """
    if default is not None:
        folder = default
    elif self.current_path and os.path.isdir(self.current_path):
        folder = self.current_path
    else:
        current_file_path = ""
        workspace_path = self.modes[self.mode].workspace_dir()
        tab = self._view.current_tab
        if tab and tab.path:
            current_file_path = os.path.dirname(os.path.abspath(tab.path))
        folder = current_file_path if current_file_path else workspace_path
    logger.info("Using path for file dialog: {}".format(folder))
    return folder


# Traceback (PermissionError)
(base) me@ubuntu:~$ mu-editor
Logging to /home/me/snap/mu-editor/common/.cache/mu/log/mu.log
Gtk-Message: Failed to load module "gail"
Gtk-Message: Failed to load module "atk-bridge"
Gtk-Message: Failed to load module "canberra-gtk-module"
Traceback (most recent call last):
File "/snap/mu-editor/4/lib/python3.5/site-packages/mu/logic.py", line 1075, in select_mode
self.change_mode(new_mode)
File "/snap/mu-editor/4/lib/python3.5/site-packages/mu/logic.py", line 1112, in change_mode
self.modes[mode].workspace_dir()))
File "/snap/mu-editor/4/lib/python3.5/site-packages/mu/modes/adafruit.py", line 98, in workspace_dir
mount_output = check_output(mount_command).splitlines()
File "/snap/mu-editor/4/usr/lib/python3.5/subprocess.py", line 626, in check_output
**kwargs).stdout
File "/snap/mu-editor/4/usr/lib/python3.5/subprocess.py", line 693, in run
with Popen(*popenargs, **kwargs) as process:
File "/snap/mu-editor/4/usr/lib/python3.5/subprocess.py", line 947, in __init__
restore_signals, start_new_session)
File "/snap/mu-editor/4/usr/lib/python3.5/subprocess.py", line 1551, in _execute_child
raise child_exception_type(errno_num, err_msg)
PermissionError: [Errno 13] Permission denied

# Fixed code
def get_dialog_directory(self, default=None):
    """
    Return the directory folder which a load/save dialog box should
    open into. In order of precedence this function will return:

    0) If not None, the value of default.
    1) The last location used by a load/save dialog.
    2) The directory containing the current file.
    3) The mode's reported workspace directory.
    """
    if default is not None:
        folder = default
    elif self.current_path and os.path.isdir(self.current_path):
        folder = self.current_path
    else:
        current_file_path = ""
        try:
            workspace_path = self.modes[self.mode].workspace_dir()
        except Exception as e:
            # Avoid crashing if workspace_dir raises, use default path
            # instead
            workspace_path = self.modes["python"].workspace_dir()
            logger.error(
                (
                    "Could not open {} mode workspace directory"
                    'due to exception "{}". Using:'
                    "\n\n{}\n\n...to store your code instead"
                ).format(self.mode, e, workspace_path)
            )
        tab = self._view.current_tab
        if tab and tab.path:
            current_file_path = os.path.dirname(os.path.abspath(tab.path))
        folder = current_file_path if current_file_path else workspace_path
    logger.info("Using path for file dialog: {}".format(folder))
    return folder