trunk: Removing ID attribute from object (XML editor) causes crash (rev >= 10992)

[su_v]

As discussed on the mailing list:
<http://thread.gmane.org/gmane.comp.graphics.inkscape.devel/41947/focus=41995>

Steps to reproduce:
1) launch trunk (default prefs, default new doc (not localized))
2) draw rect
3) switch back to select tool
4) open 'File > Export PNG image'
5) open 'Edit > XML Editor'
6) delete id of rect in XML Editor
7) deselect and reselect the rect on-canvas
--> crash

Variations as described by the original reporter (with custom preferences):
x) Manifestation 1: Choose "select" tool, click away from rect and then click rect again. Inkscape dies with "unhandled exception (type std::exception) in signal handler:\n what: basic_string::_S_construct null not valid"
x) Manifestation 2: Don't choose the select tool, just click the rect with the rect tool. Inkscape dies with "terminate called after throwing an instance of 'std::logic_error' \n what(): basic_string::_S_construct null not valid"

Crash reproduced with current trunk r12836 on OS X 10.7.5.

Based on tests with archived builds on OS X:
- not reproduced with rev <= 10990,
- reproduced with rev >= 10992,
this crash was likely introduced with in
Revision 10992: Fix for bug #171579 : Make inkscape remember dialogs window status
<http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/10992>

[Alvin Penner (apenner)]

on XP, Inkscape rev 12792, I have not been able to produce a crash, but I am getting various warnings, as below:

(inkscape.exe:3460): Gtk-CRITICAL **: gtk_window_set_transient_for: assertion `parent == NULL || GTK_IS_WINDOW (parent)' failed

(inkscape.exe:3460): GLib-GObject-WARNING **: invalid uninstantiatable type `(null)' in cast to `GtkWidget'

(inkscape.exe:3460): Gtk-CRITICAL **: gtk_widget_get_window: assertion `GTK_IS_WIDGET (widget)' failed

(inkscape.exe:3460): Gdk-WARNING **: gdkdrawable-win32.c:2013 drawable is not a pixmap or window

[jazzynico (jazzynico)]

Reproduced on Crunchbang Waldorf, Inkscape trunk revision 12836.
Same console message, (almost) same backtrace.

[Martin Owens (doctormo)]

Fixed in r12910. I've given the id a default of 'object' which is then replaced by the first valid id in the selection.

[DerekDreery (richard-o-dodd)]

I had this issue in Inkscape 0.91 r13725 (Oct 2 2015). It occured immediately after deleting an id from an arc in the xml editor, without any other user interaction.