STP.stacktrace is not strictly compatible to debug.traceback: It returns two values, instead of one. This creates problems in conjunction with varargs functions and those created through the Lua C API (which will happily consume the additional argument, creating an unexpected stack layout).
Is this something you want to fix?
--- a/src/StackTracePlus.lua
+++ b/src/StackTracePlus.lua
@@ -391,7 +392,7 @@ Stack Traceback
info = dumper.getinfo(level, "nSlf")
end
- return dumper:concat_lines(), original_error
+ return dumper:concat_lines()
end
--