6.17.3 Launcher fails to work with already built games

[Levrex]

After installing RenPy 6.17 (6.17.3) — the before being 15.3 or 16.6 — i'm unable to use "Build distributions" and "Check script (Lint)" functions i use the most, due to "Launching the project failed", despite it working as normally when launched via their own executables. Also getting the following error while trying to launch any of the old games (which were already built) via launcher:

I'm sorry, but an uncaught exception occurred.

After initialization, but before game start.
TypeError: Expected dict, got RevertableDict

-- Full Traceback ------------------------------------------------------------

Full traceback:
File "E:\xxx\RenPy\renpy-6.17.3-sdk\renpy\bootstrap.py", line 286, in bootstrap
renpy.main.main()
File "E:\xxx\RenPy\renpy-6.17.3-sdk\renpy\main.py", line 282, in main
renpy.style.build_styles()
File "style.pyx", line 666, in renpy.style.build_styles (gen\renpy.style.c:8883)
File "style.pyx", line 589, in renpy.style.build_style (gen\renpy.style.c:7668)
TypeError: Expected dict, got RevertableDict

Windows-XP-5.1.2600-SP2
Ren'Py 6.17.3.327

[PyTom]

Can you send me the stuff needed to repeat this? It looks like it's some sort of bug in Ren'Py, but I haven't seen it before.

[Levrex]

Here is the sample game (actual files were cut due to big file size):
https://dl.dropboxusercontent.com/u/615 ... i-test.rar

In this case, the problem lies within the following line (154) in music_list_kai.rpy, as the launcher becomes silent when it is removed:

style.mm_button_text = Style(style.button_text, properties=dict(size = 10, line_spacing = 1))

The problem is also encountered when trying to launch Touhou Mecha 1.1 and 1.5 via launcher, however i don't know what's the reason there.

[PyTom]

For what it's worth, I've finally figured this out, and it will be fixed in 6.18.