"Clean up document" counts as a 'modification', even if it doesn't do anything in certain circumstances

[rickmastfan67]

Inkscape 0.91pre3 r13670 (win64) & Inkscape 0.48.5 r10040 (win32)
Windows 7 x64 SP1

Steps to reproduce:
1. Start with a fresh preferences file.
2. Start Inkscape.
3. Load ANY saved SVG file on your hard drive that you know for sure has no unused 'defs'. (or take attachment from Bug #1405378 to use for this as it has no 'unused defs' already for sure)
4. File > Vacuum Defs (0.48.5) or File > Clean up document (0.91)
5. Notice that in the status bar says 'No unused definitions in < defs >' (same in both versions) (also note nothing is logged in the undo history as nothing has been done to the file)
6. Now 'File > Save As' and save the file in another location (or just add a number to it and save in the same place).
7. Repeat Step #4.

What happens:
Inkscape runs the 'Vacuum Defs' or 'Clean up document', but doesn't modify the document since there was nothing to 'clean up' (as confirmed by steps #4/5) and shows that it ran in the undo history menu. You can now also re-save the file again if you want to as Inkscape thinks it was changed when it wasn't.

What should happen:
You should get the message you get in Step #5 again in the status bar because you proved in Steps #4/5 that there is nothing to clean up.

[jazzynico (jazzynico)]

Reproduced on Windows XP, Inkscape trunk rev. 13828.
Diff confirms the documents are perfectly identical before and after the "Clean up document" command.

[Nathan Lee (nathan.lee)]

Hi - thanks for reporting this bug, I've manually migrated it to Inkscape's new
bug tracker on GitLab, and closed it here.

Please feel free to file new bugs about the issues you're seeing at
http://inkscape.org/report.

Moved to: https://gitlab.com/inkscape/inbox/issues/1567
Closed by: https://gitlab.com/nathanal