How long does damage resistance granted by Wish last?

Question

One of the possible effects you can create with the 9th level spell Wish states:

You grant up to ten creatures that you can see resistance to a damage type you choose.

And that's it. No length of time is defined, and the Duration of the spell itself is Instantaneous. Thus, my question is this: Does this mean that:

• The duration of the effect is Permanent, and thus lasts until dispelled?
• The effect is Instant and effects a permanent change in the targets?
• It's an error, and the description was supposed to list a Duration (say, 8 hours)?

My best guess is that it's the latter; the effect is probably supposed to be temporary but the bug slipped past QC.

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Answer 1

By RAW, the effect lasts indefinitely, and can't be dispelled.

The rules as written are quite clear: Up to ten creatures you can see gain resistance to a damage type of your choice. Full stop. They are not magically buffed with resistance, but instead their very nature changes such that they gain resistance. You can't dispel anything because there is nothing to dispel.

The rules as intended are much harder to prove, but I'd note that all of the effects seem to be meant as examples of the extraordinary things that the players can do. They set a baseline of what the players can do with the Wish spell, and an estimate of how powerful it is meant to be. Overall, if you really look at what a Wish spell can do, the permanent resistance isn't all that spectacular. Useful, certainly, but by no means game-breaking, at least not by Wish's standards.

Answer 2

The resistance is permanent, and cannot be dispelled.

Wish's duration is Instantaneous:

Many spells are instantaneous. The spell harms, heals, creates, or alters a creature or an object in a way that can't be dispelled, because its magic exists only for an instant.

(PHB: 203)

This duration applies to all parts of Wish that do not specifically override it. So while there is an 8 hour limit on granting immunity to a single spell, that limit applies only to that specific clause.