Simplify cinnamon-menu-editor

[fredcw]

cinnamon-menu-editor:
Remove item cut/copy/paste from menu editor and add menu category selection to desktop editor instead so that instead of the menu editor adding <Include> and <Exclude> rules to the .menu file when launchers are added to/removed from categories, the desktop editor adds/removes categories to the Categories= field in the .desktop file.
Remove code related to separators and menu layout/ordering as these are not used in cinnamon applets.
Add "Restore Item" button and remove "Close" button.
Handle flatpak apps properly.

cinnamon-desktop editor:
Add menu category selection for launcher editor.
Add "Hide (NoDisplay)" toggle for launcher editor and directory editor.
Remove unnecessary <Include> and <Exclude> rules from the .menu file added in previous versions of menu-editor when a .desktop file is updated.
Show a warning infobar when editing a local file when no "restore" to system is available.
Don't create a new .desktop file in ~/.local/share/applications if original is in a subdirectory of ~/.local/share/applications as it would be overriden anyway and edit original instead.
Add command line option --show-categories so that unnecessary complexity can be avoided when launched from the app menu.

config.py:
delete unused constants

cinnamon-applications.menu:
simplify logic in "Administration" menu
remove unused "System" menu

Fixes #12890, #11998, #10139, #10581, #10140, #10141, #9293, #7961

Replaces: #13346

Known issues:
Using Categories key in .desktop file instead of <Include> and <Exclude> tags in the .menu xml means that placing an app in some combinations of categories is not possible. An app can't be in Education and Science at the same time, in Universal Access and Preferences at the same time, or in Accessories or Preferences and Administration at the same time. This was not previously the case.

While Wine apps can be added to other categories, they cannot be removed from the Wine category as Wine creates its own .menu file with <Include>'s. This was very likely previously also the case.

Apps installed locally have no "Restore" (to system default) option once edited. This was previously also the case. This includes Wine apps, Steam games, Chrome's PWAs. I have added a warning banner to the editor when the user is editing a locally installed .desktop or .directory file with no restore to system available.

[mtwebster]

I don't know how useful 'NoDisplay' is here - that's usually reserved for content handlers (Open with... in nemo) or autostart programs (nemo-desktop uses this) - things you don't want to appear in the menu.

So it's basically a 'hide' button for the menu - and if you're not using the entry as a content handler and it's not autostart, you may as well not have it. I think it should probably be left to advanced users, it'll just confuse people who are customizing their menu.

I wonder if those category limitations mentioned are caused by our customizations in our default menu file.

How will this affect people who already have made customizations?

I'd like @clefebvre's input on this (and the UI changes in the desktop-editor). I like the idea of just relying on desktop files here.

claude review:

 Critical Issues (2)                                                                                                 
                                                                                                                      
  1. getIsItemUserOrSystem crashes on unexpected item types — MenuEditor.py                                           
                                                                        
  If item is neither CMenu.TreeEntry nor CMenu.TreeDirectory, user_exists and system_exists are never assigned,
  causing UnboundLocalError. Should initialize both to False before the if/elif:

  def getIsItemUserOrSystem(self, item):
      user_exists = False
      system_exists = False

      if isinstance(item, CMenu.TreeEntry):
          ...
      elif isinstance(item, CMenu.TreeDirectory):
          ...

  2. getUserMenuXml() doesn't handle _getSystemMenuPath() returning None — util.py

  If no system menu file is found, the generated XML will contain <MergeFile type="parent">None</MergeFile> (literal
  string "None"), silently corrupting the menu configuration. Should raise an error or omit the element when
  system_file is None.

  Important Issues (6)

  3. _save() in MenuEditor has no error handling — MenuEditor.py

  File write can fail (permissions, disk full). No try/except means the app crashes with an unhandled traceback.

  4. ItemEditor.save() prints error but gives no user feedback — cinnamon-desktop-editor.py

  On IOError, only prints to stdout (invisible in a GUI app). The dialog closes as if save succeeded, and
  self.callback(True, ...) is still called. User thinks changes were saved when they weren't.

  5. Bare except Exception in _loadDOM() — MenuEditor.py

  Old code caught specific (IOError, xml.parsers.expat.ExpatError). New code catches all Exception, silently
  swallowing PermissionError etc. Should narrow to except (FileNotFoundError, ET.ParseError).

  6. Grammar: "it's" should be "its" in two translatable strings — MainWindow.py

  Two user-facing strings use "it's" (contraction of "it is") where possessive "its" is needed:
  - "...delete it's associated .desktop file..."
  - "...and it's associated .directory file..."

  7. Trailing whitespace — Multiple files

  ~15+ new lines have trailing whitespace across cinnamon-desktop-editor.py, MainWindow.py, MenuEditor.py, and
  util.py.

  8. Tab/space inconsistency — cinnamon-applications.menu

  New <Menuname>Science</Menuname> uses 2 spaces while all surrounding entries use tabs.

  Minor Issues (4)

  9. Debug print() left in _on_edit_properties_activate — MainWindow.py

  Bare print() outputs an empty line to stdout. Debug leftover.

  10. Over-indented return node in _getXmlMenuPart — MenuEditor.py

  Has 20 spaces of indentation instead of 16. Valid Python but visually misleading — looks like it belongs to a deeper
   nesting level that no longer exists.

  11. _clear_menu_overrides() uses bare except Exception — cinnamon-desktop-editor.py

  Catches everything and only prints to stdout. Should narrow to except (ET.ParseError, OSError) and consider showing
  a warning since stale overrides can affect menu behavior.

  12. Comment says "custom launcher" in DirectoryEditor.check_custom_path — cinnamon-desktop-editor.py

  Says "custom launcher" but this handles .directory files. Should say "custom directory" or "custom menu category".

  Strengths

  - Net deletion of 253 lines — genuine simplification
  - Clean architectural shift: category management via .desktop Categories= field instead of .menu XML
  <Include>/<Exclude> rules
  - Good switch from xml.dom.minidom to xml.etree.ElementTree
  - Proper flatpak handling with .removesuffix(":flatpak")
  - Correctly removes stale comments referencing removed functionality
  - Replaces polling with GLib.child_watch_add
  - Well-written _fdo_to_cinnamon / _cinnamon_to_fdo mapping comments referencing the .menu file
  - Good warning infobar for locally-installed apps with no system restore available

[fredcw]

I don't know how useful 'NoDisplay' is here - that's usually reserved for content handlers (Open with... in nemo) or autostart programs (nemo-desktop uses this) - things you don't want to appear in the menu.

I've no objection to this being removed, however, I can think of a couple of reasons some people might find it useful: To show an item hidden by default, e.g. cinnamon-menu-editor itself (although tbf, that's the only one I've come across), and to hide items e.g. if something is installed as a dependency of another package but you know you'll never use it. e.g. VSCodium (manjaro) installs two icons, "VSCodium" and "VSCodium (Wayland)", user may want to hide one of them if they only use x11 or wayland. LibreOffice, they may want to show LibreOffice Writer but not LibreOffice Impress. Some utilities e.g. "Avahi Zeroconf Browser" (Manjaro) is installed as a dependency of many packages but some users may never use it and want to hide it.

I wonder if those category limitations mentioned are caused by our customizations in our default menu file.

Yes, e.g. the "Education" category contains the rule: <Not><Category>Science</Category></Not> so if user selects both "Education" and "Science" categories in cinnamon-desktop-editor, the app will only appear in "Science" menu. I haven't added any feedback or info to the user regarding this so some users may think it's a bug. I can't think of a non-complicated way to give feedback to the user regarding these specific limitations.
Edit: I added feedback for this. Mutually exclusive categories cannot now be selected at the same time as selecting on will toggle the other off.

How will this affect people who already have made customizations?

It won't affect them initially, their existing customizations will continue to take effect. That changes when they edit the properties of an already customized app. In cinnamon-desktop-editor, the selected categories will reflect those in the .desktop "Categories=" key, rather than their previous customisations. If they then click "OK", their selected categories (in the cinnamon-desktop-editor dialog) will be written to the .desktop file and all <Include> and <Exclude> rules relating to that particular app will be removed from the .menu file. So basically, they'll have to ensure that they select the categories they want the app to appear in before clicking "OK". While not ideal, this should be somewhat intuitive as they may see that their previously customised category selections appear to have been reset and therefore "fix" them. Preselecting the categories based on the existing <Include> and <Exclude> rules in the menu xml file would be fairly complicated I think.

Note: I also added a command line option for cinnamon-desktop-editor, --show-categories. I added this so that when cinnamon-desktop-editor is called from cinnamon-menu-editor --show-categories is included. But when called from the app menu, it isn't (categories section of the dialog will be hidden). My thinking is that showing the categories when opened from the app menu may encourage casual users to start rearranging their menu when they don't really need to and the FDO desktop spec is not really the most user friendly way of doing this. I can of course remove this if that's preferred.

[fredcw]

Fixed all Claude suggestions except number 2. If /etc/xdg/menus/cinnamon-applications.menu is missing, user probably has bigger fish to fry since their app menu will be empty anyway. Also, this would not be the place to detect that problem as <MergeFile type="parent">None</MergeFile> would just be ignored by the xml parser anyway.

Added atomic save in menu editor when saving user's cinnamon-applications.menu file.

Added feedback when selecting mutually exclusive categories in cinnamon-desktop-editor, e.g. when toggling on "Education", "Science" will automatically toggle off and vice versa.

Added error dialog to cinnamon-desktop-editor when there's a write error.

[JosephMcc]

Probably shouldn't use Gtk.STOCK_* in new code.