Invalid trans type error

[shin258]

Describe the bug

An Invalid trans type happen with the stage : Crystalline Cavern by Hihoshi (winmugen (plus) version) lead to this:

Version: nightly
Build Time: 2026.05.19
Platform: windows (amd64)
OpenGL 3.3
RAM in Use: 467 MB / OS Reserved: 808 MB
Active Goroutines: 2
Timestamp: 2026-05-19 22:46:57

Engine error

Error: .\external\script\start.lua:1654:
Error loading stages/Crystalline.def: Invalid trans type:
stack traceback:
[G]: in function 'game'
.\external\script\start.lua:1654: in function 'f_game'
.\external\script\start.lua:2232: in function 'launchFight'
external/script/default.lua:2: in function <external/script/default.lua:0>
.\external\script\start.lua:1710: in function 'f'
external/script/main.lua:2407: in function 'loop'
external/script/main.lua:3728: in main chunk
[G]: ?

Go stack traceback:
goroutine 1 [running, locked to thread]:
runtime/debug.Stack()
runtime/debug/stack.go:24 +0x65
main.handlePanic({0x7ff7fa6bc360?, 0xc0086b2040})
github.com/ikemen-engine/Ikemen-GO/src/main.go:362 +0x3e5
main.realMain.func1()
github.com/ikemen-engine/Ikemen-GO/src/main.go:66 +0x2a
panic({0x7ff7fa6bc360, 0xc0086b2040})
runtime/panic.go:884 +0x213
main.realMain()
github.com/ikemen-engine/Ikemen-GO/src/main.go:206 +0x573
main.main()
github.com/ikemen-engine/Ikemen-GO/src/main.go:59 +0x17

PS: maybe link to the reflection error on 0.99(more research in progress)

To Reproduce

1. Download the two stage for test and compare : https://mugenfreeforall.com/topic/24193-hihoshi-stage-collection/ (Crystalline Cavern)
2. Select the stage (principally the winmugen (plus) version) lead to this error.

Expected behavior

Work as same as winmugen plus or mugen 1.0/1.1

Engine Version (or source code date)

Devbuild

Operating system

Windows

[potsmugen]

The stage has a BG where trans is (unsurprisingly) invalid:

[BG 117]
type = normal 
layerno =1
spriteno = 1, 40
start = 74880, 0
delta = 640, 2
mask = 1
trans = 

We could probably make that be tolerated for older stages or something. But until then I rather our default behavior be to crash than to fail silently like Mugen.

[shin258]

The stage has a BG where trans is (unsurprisingly) invalid:

[BG 117]
type = normal 
layerno =1
spriteno = 1, 40
start = 74880, 0
delta = 640, 2
mask = 1
trans = 

We could probably make that be tolerated for older stages or something. But until then I rather our default behavior be to crash than to fail silently like Mugen.

With remove this line it work , also the mugen 1.0 version work too by default problem solved thanks for your time.