Allow user to select a specific IWAD file for a (custom) game session
Right now, Doomsday locates by name game data. After it finds a list of candidate files, it selects the one which matches exactly the criteria for that game data file. Said criteria include a list of map names, and miscellaneous lumps. This can pose an issue in the case of both testing, and third-party game data (e.g. HACX 2.0). Although it may not be guaranteed at search-time that a non-matching IWAD is compatible with the engine, it is a comparably better experience that what is currently involved in getting the engine to select a non-standard IWAD. As an aside, this also allows for users to name game data in such a way that it is distinct from other data -- e.g. (doom, doom1, etc...).
#1 Updated by danij about 7 years ago
This is looking at the problem from the wrong perspective. Rather than overriding an IWAD for a pre-defined game mode one should instead be able to define an entirely new game mode configuration and then bundle both into a dynamically loaded package. Otherwise, runtime game selection can't really work correctly because the cart is before the horse.
If the intention is to override the IWAD data for a pre-defined game mode then the canonical way to do so is to load a PWAD on top.