It does not crash, but now clicking after the last character or between the last two characters will place the cursor before the last two characters. I submitted an (untested) alternative patch on the upstream bug, maybe it helps?

fixes my textbox crashes

fixes my textbox crashes

May I have a link to that patch, please?

https://launchpadlibrarian.net/405852336/inkscape-0.92.3-oob.patch

--- src/libnrtype/Layout-TNG-OutIter.cpp.orig   2019-01-11 19:56:12.701209914 +0100
+++ src/libnrtype/Layout-TNG-OutIter.cpp    2019-01-11 19:58:19.624114664 +0100
@@ -46,7 +46,8 @@
             best_x_difference = this_x_difference;
         }
     }
-    if (best_char_index == -1) return iterator(this, char_index);
+    if (best_char_index == -1) best_char_index = char_index;
+    if (best_char_index == _characters.size()) return end();
     return iterator(this, best_char_index);
 }

Awesome! Most of those bugs are fixed now. I'm seeing same behaviour the anonymous user reported.

File from #1573152 still crashes inkscape, but only when using Open with... -> inkscape (in Cinnamon). Drag'n'drop or Open menu in inkscape loads it successfully.

With steps from #1612618 i still can reproduce the crash.

Hmm, yes, #1612618 still crashes, so I tried it in gdb. This is half-guessing (i.e. untested): in src/libnrtype/Layout-TNG-OutIter.cpp, there is the function

bool Layout::iterator::nextLineCursor(int n) {
    // ...
    _char_index = _parent_layout->_cursorXOnLineToIterator(line_index + n, _x_coordinate)._char_index;
    _glyph_index = _parent_layout->_characters[_char_index].in_glyph;
    return true;
}

_char_index can actaully be _characters.size(), so I think it could be fixed by changing the last lines to:

bool Layout::iterator::nextLineCursor(int n) {
    // ...
    _char_index = _parent_layout->_cursorXOnLineToIterator(line_index + n, _x_coordinate)._char_index;
    if (_char_index == _characters.size())
        _glyph_index = _glyphs.size();
    else
        _glyph_index = _parent_layout->_characters[_char_index].in_glyph;
    return true;
}

(Sorry if this is not the right place to post tentative patches.)

s/_characters.size()/_parent_layout->_characters.size()/
s/_glyphs.size()/_parent_layout->_glyphs.size()/

I've had the best luck with https://launchpadlibrarian.net/405852336/inkscape-0.92.3-oob.patch by itself. I'll update to use that.