Have you tried messing with the launch options? I've used that to debug source mods before by launching a terminal and having it execute a script. I'm not at my desktop right now, so I don't know the exact command, but it was something like your-favorite-terminal --someswitch bash -c "gdb /path/to/executable" && echo %command%

Thanks for reporting. The spaces issue will be fixed in the next build. In the meantime, you can workaround by putting quotes around the path in the first line of that /tmp/ file.

The scripts are sparely documented at the top of each script. They could be more thorough, I guess, but they're each like 3 lines long and shouldn't be too hard to figure out alongside the winedbg manpage. They're not really intended for use by end-users.

Note that winedbg itself isn't terribly robust or well documented, but that's not a Proton issue per se =/

Here's a super trivial session example (with some junk trimmed):

[aeikum@aeikum ~]$ /tmp/proton_aeikum/gdb_run 
0027:0028: create process ''/0x110c90 @0x4f9a16 (0<0>)
0027:0028: create thread I @0x4f9a16
...
0027:0028: loads DLL  @0x7d300000 (0<0>)
00000027:00000028: exception code=0x80000003
warning: remote target does not support file transfer, attempting to access files from local filesystem.
warning: Could not load shared library symbols for linux-gate.so.1.
Do you need "set solib-search-path" or "set sysroot"?
start_process (entry=0x4f9a16, peb=0x7ffdf000) at /home/proton/proton/wine/dlls/kernel32/process.c:1099
1099	/home/proton/proton/wine/dlls/kernel32/process.c: No such file or directory.


Wine-gdb> break SetWindowPos
Breakpoint 1 at 0x7e756770: file /home/proton/proton/wine/dlls/user32/winpos.c, line 2338.


Wine-gdb> c
Continuing.
...
00000027:00000028: exception code=0x80000003

Breakpoint 1, SetWindowPos (hwnd=0x2004e, hwndInsertAfter=0x0, x=0, y=0, cx=0, cy=0, flags=67) at /home/proton/proton/wine/dlls/user32/winpos.c:2338
2338	/home/proton/proton/wine/dlls/user32/winpos.c: No such file or directory.


Wine-gdb> bt
#0  SetWindowPos (hwnd=0x2004e, hwndInsertAfter=0x0, x=0, y=0, cx=0, cy=0, flags=67) at /home/proton/proton/wine/dlls/user32/winpos.c:2338
#1  0x7e757aa2 in show_window (hwnd=0x2004e, cmd=5) at /home/proton/proton/wine/dlls/user32/winpos.c:1152
#2  0x7e757d48 in ShowWindow (hwnd=0x2004e, cmd=5) at /home/proton/proton/wine/dlls/user32/winpos.c:1250
#3  0x0067dc15 in ?? ()
#4  0x0067c1b5 in ?? ()
#5  0x004f2158 in ?? ()
#6  0x004c49e3 in ?? ()
#7  0x004c4836 in ?? ()
#8  0x00437164 in ?? ()
#9  0x004f9b41 in ?? ()
[#10](/issue/ValveSoftware/Proton/10) 0x7b4611dc in call_process_entry () from /home/aeikum/.local/share/Steam/steamapps/common/Proton 3.7 Beta/dist/bin/../lib/wine/kernel32.dll.so
[#11](/issue/ValveSoftware/Proton/11) 0x7b462a36 in start_process (entry=0x4f9a16, peb=0x7ffdf000) at /home/proton/proton/wine/dlls/kernel32/process.c:1099
[#12](/issue/ValveSoftware/Proton/12) 0x7b4611ea in start_process_wrapper () from /home/aeikum/.local/share/Steam/steamapps/common/Proton 3.7 Beta/dist/bin/../lib/wine/kernel32.dll.so
[#13](/issue/ValveSoftware/Proton/13) 0x00000000 in ?? ()


Wine-gdb>

Edit: I tried to make the input prompts more obvious.

Great, that's really helpful!

I know it's a pretty broad question, but do you have any other wine debugging tips, in particular around games? Or general resources? I've read through the wine debugging FAQ, but can't shake the feeling that there are more tricks most wine devs just know.

E.g. breaking on SetWindowPos seems to be a pretty good idea in my use case, as it breaks pretty soon before where I suspect it crashes.

For me, debugging Wine issues, I use the debug log most often. I rarely use a debugger. Add log channels relevant to the problem you're having, and look for err: and warn: lines for obvious failures. If the program is just quitting unexpectedly, you can add +relay and look backwards from ExitProcess to find the last bit of what looks like "normal processing" to find the failure. +seh will show you exceptions, c0000005 indicates a bad pointer dereference, which will often be preceded by some sort of failure.

Cool thanks! Managed to make Little Nightmares run somewhat yesterday evening, partly thanks to your hints :)

Closing for now, but I'd love to have a bit more of a guide or collections of hints like that at some point. I'd write up some myself, but I don't think I know quite enough yet.