trunk: crash when selecting text object with empty 'font-family' property (rev >= 12104)

[su_v]

Inkscape trunk crashes on selecting a text object which has an empty 'font-family' style property. Independent of whether this is conformant SVG or not (needs to be verified), Inkscape ought to handle this more gracefully and not crash.

Steps to reproduce:
1) launch inkscape (default prefs, default new doc)
2) open the attached SVG file
3) select the bottom-most text object

Expected result:
Inkscape selects the text object and displays object information in the status bar.

Actual result:
Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: 13 at address: 0x0000000000000000
0x000000010427e863 in Glib::ustring::empty ()
(gdb) bt
#0 0x000000010427e863 in Glib::ustring::empty ()
#1 0x000000010072bc35 in Inkscape::FontLister::update_font_list (this=0x10e0b8cc0, document=0x10aec6c00) at font-lister.cpp:158
#2 0x00000001009e0392 in sp_text_toolbox_selection_changed (unnamed_arg=0x10d81a0f0, tbl=0x10b51aa20) at text-toolbar.cpp:867

First encountered with Inkscape 0.48+devel r12588 on OS X 10.7.5

Based on tests with archived builds on OS X:
 - not reproduced with rev <= 12103
 - reproduced with rev >= 12104,
this regression seems related to:
Revision 12104: Add fonts (and font-lists) used in document to top of Text tool-bar font-family drop-down menu.
<http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/12104>

[su_v (suv-lp)]

Note: the sample SVG file was created with (unreleased) lp:inkscape/0.48.x r9968, which includes the backported fix for
- Bug #805238 “Crash when setting empty font family”
  <https://bugs.launchpad.net/inkscape/+bug/805238>

The backported fix has been reverted for now in lp:inkscape/0.48.x r9969.

[su_v (suv-lp)]

Backtrace

[jazzynico (jazzynico)]

Confirmed on Windows XP, Inkscape trunk revision 12688.

[Johan Engelen (johanengelen)]

should be fixed in r12740

[jazzynico (jazzynico)]

Tested on Windows XP, Inkscape trunk revision 12742.
Inkscape no longer crashes when selecting the text object (step 3 in the original description).

But now the following steps lead to another crash:
1. Select one of the text objects.
2. Select the Text tool.
3. Open the font selector in the tools options bar -> at the top of the list, we now have two lines: one with Sans, the other with an apparently random font.
4. Move the mouse cursor on the top of the list -> the random font changes to Sans. We now have two Sans lines.
5. Select the first line (the one that changes in 4) -> Inkscape crashes.

Sorry, I didn't manage to get a gdb trace on Windows.

[Johan Engelen (johanengelen)]

nice testing, I think Tav should have a look at this too

[jazzynico (jazzynico)]

Bug from comment #6 reproduced on Crunchbang Waldorf, Inkscape trunk revision 12849.

Console message:
'std::logic_error' what(): basic_string::_S_construct null not valid

GDB trace attached.

[jazzynico (jazzynico)]

When moving the mouse cursor on the two top fonts, the application outputs the following console messages:
----
(inkscape:5402): Gtk-WARNING **: Failed to set text from markup due to error parsing markup: Error on line 1 char 68: 'gray'' is not a valid name: '''
(repeated many times).
----

And just before crashing, I get:
----
** (inkscape:5402): WARNING **: Ignoring font without family that will crash Pango
** Message: Family: (null)
----

 The g_message is a local test on the result of pango_font_description_get_family(descr), in libnrtype/font-lister.cpp:288.

[Martin Owens (doctormo)]

I've fixed it in r12908 by setting a default if pango fails to get a family name. This not only prevents the crash but looks more consistent in the UI.

[su_v (suv-lp)]

@Martin - JFYI: the default generic/fallback font in trunk is 'sans-serif', and no longer 'Sans'. Trunk had been switched from 'Sans' to 'sans-serif' in revision 11393:
<http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/11393>

[Martin Owens (doctormo)]

Thanks suv, updated in 12909