Why do some Dehacked patches rename edited sprites instead of just having the sprites override the original ones directly?

[SavebearingBoss]

In, for example, Knee-Deep In Knee-Deep In ZDoom, there's a Dehacked lump in which various sprite names are changed, such as "AMMO" to "RAMO", using the text section, similar to changing intermission messages & the like. (this also makes WhackEd4 not able to view the .deh file properly, saying "The engine string could not be found.It will not be loaded.")
Obviously the sprites themselves were edited to fit the wad's new palette & colormap, but why not just have them named "AMMO" instead? Is there some quirk about the vanilla engine that necessitates this?

[Arsinikk]

34 minutes ago, SavebearingBoss said:

 Obviously the sprites themselves were edited to fit the wad's new palette & colormap, but why not just have them named "AMMO" instead? Is there some quirk about the vanilla engine that necessitates this?

Yes, for new sprites to work in Vanilla, they must be renamed to prevent Vanilla from crashing.

 

This is because there's a quirk in Vanilla, where if one sprite name is replaced in a PWAD, it expects the entirety of all Doom/Doom II sprites to also be replaced. Obviously we don't want to do that. However adding newly named sprites is supported in Vanilla, and so something like "RAMO" instead of "AMMO" would not result in a crash.

 

These Dehacked Sprite blocks were added for this specific reason giving mappers the ability to replace sprites using alternate names to avoid a crash. Obviously from BOOM forward, this sorta of quirk was fixed, just allowing the normal replacing of sprites.

Edited February 11 by Arsinikk