ui: fix raylib log message formatting by handing va_list arguments (#35561)

* fix raylib log message formatting by handing va_list arguments

* dd

* improve&simplify

* chadder says this works

* consis

* clean up

---------

Co-authored-by: Shane Smiskol <shane@smiskol.com>

system/ui/lib/application.py

@@ -1,4 +1,5 @@
 import atexit
+import cffi
 import os
 import time
 import pyray as rl
@@ -246,12 +247,29 @@ class GuiApplication:
     rl.gui_set_style(rl.GuiControl.DEFAULT, rl.GuiControlProperty.BASE_COLOR_NORMAL, rl.color_to_int(rl.Color(50, 50, 50, 255)))
 
   def _set_log_callback(self):
+    ffi_libc = cffi.FFI()
+    ffi_libc.cdef("""
+      int vasprintf(char **strp, const char *fmt, void *ap);
+      void free(void *ptr);
+    """)
+    libc = ffi_libc.dlopen(None)
+
     @rl.ffi.callback("void(int, char *, void *)")
     def trace_log_callback(log_level, text, args):
       try:
-        text_str = rl.ffi.string(text).decode('utf-8')
+        text_addr = int(rl.ffi.cast("uintptr_t", text))
-      except (TypeError, UnicodeDecodeError):
+        args_addr = int(rl.ffi.cast("uintptr_t", args))
-        text_str = str(text)
+        text_libc = ffi_libc.cast("char *", text_addr)
+        args_libc = ffi_libc.cast("void *", args_addr)
+
+        out = ffi_libc.new("char **")
+        if libc.vasprintf(out, text_libc, args_libc) >= 0 and out[0] != ffi_libc.NULL:
+          text_str = ffi_libc.string(out[0]).decode("utf-8", "replace")
+          libc.free(out[0])
+        else:
+          text_str = rl.ffi.string(text).decode("utf-8", "replace")
+      except Exception as e:
+        text_str = f"[Log decode error: {e}]"
 
       if log_level == rl.TraceLogLevel.LOG_ERROR:
         cloudlog.error(f"raylib: {text_str}")