Do not throw on malformed Desktop Entries on Linux.

This just skips the malformed entry when it's found.

Fixes #899

dangerzone/gui/logic.py

@@ -24,7 +24,7 @@
  from PySide2 import QtCore, QtGui, QtWidgets
 
 if platform.system() == "Linux":
- from xdg.DesktopEntry import DesktopEntry
+ from xdg.DesktopEntry import DesktopEntry, ParsingError
 
 from ..isolation_provider.base import IsolationProvider
 from ..logic import DangerzoneCore
@@ -123,27 +123,37 @@ def _find_pdf_viewers(self) -> OrderedDict[str, str]:
  full_filename = os.path.join(search_path, filename)
  if os.path.splitext(filename)[1] == ".desktop":
  # See which ones can open PDFs
- desktop_entry = DesktopEntry(full_filename)
- desktop_entry_name = desktop_entry.getName()
- if (
- "application/pdf" in desktop_entry.getMimeTypes()
- and "dangerzone" not in desktop_entry_name.lower()
- ):
- pdf_viewers[desktop_entry_name] = (
- desktop_entry.getExec()
+ try:
+ desktop_entry = DesktopEntry(full_filename)
+ except ParsingError:
+ # Do not stop when encountering malformed desktop entries
+ continue
+ except Exception:
+ log.exception(
+ "Encountered the following exception while processing desktop entry %s",
+ full_filename,
  )
-
- # Put the default entry first
- if filename == default_pdf_viewer:
- try:
- pdf_viewers.move_to_end(
- desktop_entry_name, last=False
- )
- except KeyError as e:
- # Should be unreachable
- log.error(
- f"Problem reordering applications: {e}"
- )
+ else:
+ desktop_entry_name = desktop_entry.getName()
+ if (
+ "application/pdf" in desktop_entry.getMimeTypes()
+ and "dangerzone" not in desktop_entry_name.lower()
+ ):
+ pdf_viewers[desktop_entry_name] = (
+ desktop_entry.getExec()
+ )
+
+ # Put the default entry first
+ if filename == default_pdf_viewer:
+ try:
+ pdf_viewers.move_to_end(
+ desktop_entry_name, last=False
+ )
+ except KeyError as e:
+ # Should be unreachable
+ log.error(
+ f"Problem reordering applications: {e}"
+ )
  except FileNotFoundError:
  pass
 

tests/gui/test_logic.py

@@ -7,7 +7,7 @@
 from dangerzone.gui.logic import DangerzoneGui
 
 if platform.system() == "Linux":
- from xdg.DesktopEntry import DesktopEntry
+ from xdg.DesktopEntry import DesktopEntry, ParsingError
 
 
 @pytest.mark.skipif(platform.system() != "Linux", reason="Linux-only test")
@@ -98,3 +98,25 @@ def test_mime_handers_succeeds_no_default_found() -> None:
  mock_list.assert_called()
  assert len(dz.pdf_viewers) == 3
  assert dz.pdf_viewers.popitem(last=False)[0] == "Evince"
+
+
+@pytest.mark.skipif(platform.system() != "Linux", reason="Linux-only test")
+def test_malformed_desktop_entry_is_catched() -> None:
+ """
+ Given a failure to read a desktop entry,
+ ensure that the exception is not thrown to the end-user.
+ """
+ mock_app = mock.MagicMock()
+ dummy = mock.MagicMock()
+
+ with mock.patch("dangerzone.gui.logic.DesktopEntry") as mock_desktop, mock.patch(
+ "os.listdir",
+ side_effect=[
+ ["malformed.desktop", "another.desktop"],
+ [],
+ [],
+ ],
+ ):
+ mock_desktop.side_effect = ParsingError("Oh noes!", "malformed.desktop")
+ DangerzoneGui(mock_app, dummy)
+ mock_desktop.assert_called()