First-run failure to write or load new pop file w/ BMS-Auto.key (race -condition?)

[arithex]

First reported by Prime/AviationPlus https://www.youtube.com/watch?v=sB0DukjvIp0 but I think I remember this happening to me too when I first installed 4.37.

Repro:

1. clean install
2. during first run, prompts to change callsign (let's say, "Yankee") and pilot name ("Yankee Joe")
3. launch BMS, go to Setting / Controllers screen

Observed:

• settings screen shows my new callsign "Yankee" in green, but the Controllers page indicates "BMS - Full.key" as the current key file

Expected:

• settings screen shows callsign "Yankee" and key file "BMS - Auto.key"

Further:

4. close BMS
5. restart the launcher, and launch BMS again
6. now things appear ok -- callsign is "Yankee" and key file is "BMS - Auto.key"

Theory (I haven't fully debugged this, just repro'd it):

• AL is writing the pop file and reg keys upon window-close.. but at that point it has already started the BMS child process
• BMS can see the new pilotCallsign "Yankee" set in the reg key .. but is not able to load the new "Yankee.pop" file because it's still locked for writing by AL process (or maybe even doesn't exist yet)

[arithex]

https://imgur.com/a/n299Tbq

[arithex]

Debugging this, I uncovered 1 potential race and 1 problem with the Callsign.pop file initial creation.

1- we launch 'bms-logcat.exe' and don't wait for it to complete.. that's an easy fix

2- the initial Callsign.pop file we emit, seems to be rejected by BMS and it emits its own fresh new Callsign.pop file, which points to BMS-Full.key

looking at a binary diff, what AL emits vs what BMS emits, there are quite a few bits different.. even the total size is grown by 4 bytes.

looks like we haven't refreshed that block of code since 4.35? (it's in OverrideSettingFor435.cs :)

I'll send you a PR.. you can decide what to do with it, of course. But if the pop file format has further evolved for 4.37 U3 or 4.38.. you'll have to take over.

ps I have newfound respect for the difficulty you faced building all this, without source access..