Rope Trick and Handy Haversack

[Unwise]

As a DM, I find the correct answer is to just grin and get them to make an arcana roll. If they make it, they are aware that other mages must have thought about stacking dimensional pockets, but nobody does it. When the mage's mentor was asked about it, he just said "heh, well...I wouldn't".

That is enough fair warning. They can try it if they want and if it is non-abusive, nothing happens. Now however, I have a good basis for whatever nastiness might happen if they abuse dimensional spaces. In reality though, they just know to not mess around doing stuff like that.

For me the more common issue is putting living beings and people inside bags of holding or dimensional pockets. I just handle it in the same way.

 

[nijineko]

So what exactly happens when you crawl up the rope into that extra dimensional space with your handy haversack.

technically... nothing.

however, if you wish to follow through the logical conclusion made from the bag of holding and the portable hole, reference the list of spells which use the ethereal and astral in the planar books. note that portable hole uses one, and bag of holding uses the other. the logical conclusion is that when you attempt to place one item which has an extra-dimensional space-effect based on one plane inside another object which has an extra-dimensional space-effect based on the other plane, then it will cause you some problems.

just keep in mind, that while that might be a logical extension of the concept presented, it is not actually in the rules anywhere. the bag and hole are the only two items which such a destructive interface that i recall offhand.

 

[N'raac]

From the 3.5 Rope Trick spell:

Note: It is hazardous to create an extradimensional space within an existing extradimensional space or to take an extradimensional space into an existing one.

Not much detail, other than "it's hazardous". Obviously, however, you can take one ED space into another.

A number of spells and magic items utilize extradimensional spaces, such as rope trick, a bag of holding, a handy haversack, and a portable hole. These spells and magic items create a tiny pocket space that does not exist in any dimension. Such items do not function, however, inside another extradimensional space. If placed inside such a space, they cease to function until removed from the extradimensional space. For example, if a bag of holding is brought into a rope trick, the contents of the bag of holding become inaccessible until the bag of holding is taken outside the rope trick. The only exception to this is when a bag of holding and a portable hole interact, forming a rift to the Astral Plane, as noted in their descriptions.

So nesting works in Pathfinder, but for storage, not access. I wonder how many wizards carry spell books in haversacks with the expectation of studying spells in a Rope Trick...

I seem to recall an older suggestion (Sage advice, maybe) that putting a bag or holding in a second bag of holding, or a portable hole inside another portable hole, would cause the two enchantments to nest, leaving enough extra room for some small object like a single coin or ring.