[Bug]: ICU Layouter crash

[PeterN]

Version of OpenTTD

git master 878c5d8

Expected result

No crash :-)

Actual result

openttd: ../src/gfx_layout_icu.cpp:498: virtual std::unique_ptr<const ICUParagraphLayout::Line> ICUParagraphLayout::NextLine(int): Assertion `run.length > new_partial_length' failed.

Steps to reproduce

1. Set medium font to "DejaVu Sans". (I'm using default font size, 2x interface.)
2. Open NewGRF settings window and select a NewGRF in either the upper or lower list.
3. Crash.

[PeterN]

My immediate thought is there a long string (MD5Sum!) that doesn't have any place to wrap, but that might just be coincidence.

[TrueBrain]

It happens during the drawing of MD5sum, yes. But it seems the reason why is because I kinda misunderstood how harfbuzz returns clusters. I expected the first char to be in the first cluster, but this doesn't always seems to be the case. Need to look a bit deeper what is actually going on here.