Spacing in justified text becomes incorrect after line break
This issue affects some texts shaped like the following example (short first line, long second line):
First line
We now keep writing after the line break, and eventually, strange gaps may appear in the middle of words. Depends on the font, obviously, but once you fill up a few lines, things usually start to go wrong. Apparently the length of the first line also matters. Somehow this is still not enough text, but at some point it needs to start happening, right? Maybe if we challenge it with a really long word like supercalifragilisticexpialidocious.
When rendering such a text as justified and with small enough width that the second line wraps, incorrect horizontal spacing appears all over the place in the middle of words, making the output look rather messed up. The degree to which this happens differs depending on the contents of both lines and the font used, but as long as the line break is present and the second line is long enough, there always seems to be some amount of damage.
I have tested this using the command pango-view text.txt --justified -w 350
(where text.txt contains the example given above) with a few different versions:
The oldest version shows how I would expect the spacing to look, while both of the newer ones are quite obviously getting it wrong. On the affected systems, the issue can also be reproduced by simply opening GIMP and entering the example text into a justified text box of appropriate width.