Limitation (max elements in list)

[jleni]

Due to memory constraints, we have limited the number of:

• list elements
• tuple elements

#1 (comment)

Can you confirm that this limit is acceptable? or please suggest a number that would be adequate.

[kantai]

This wouldn't be acceptable -- there are likely to be transactions involving much larger lists and tuples. However, it would be acceptable to do something like display 'list of length X with elements of type Y' for large lists and tuples.

[jleni]

We have limitations on the amount of RAM (~2kB) and NVRAM (~8kB) in Nano S. For this reason, we need to set some maximum values. In multiple places, we are already pre-parsing and indexing and later parsing on demand as the user navigates the information. Still, we we need to set some limits and see if we can fit them.

Nano X can definitely have higher limits (~38kB RAM).

What would you suggest as an acceptable limit that still is useful in 90% of the cases?

[kantai]

What's running out of memory in the parser here? Is it the parser itself? Or is the object being constructed too large? I think it should be possible to address this by not parsing large lists/tuples, and instead providing some kind of stand-in/summary value for the large object.

[jleni]

Well, it is a combination of all those.. we need to balance storage, call stack consumption plus work out a way to format and present the information.

Yes, we normally do all these things and many other tricks and somersault.. :)

I think the point is: we try to concentrate the effort in areas that are required. We were not sure what was the value we need to target. Having a number if mind helps to see how/where to spend more time and if we need to use some more complex approaches.

[kantai]

I see -- I think a limit of ~10 is more reasonable and would handle most cases, however, I think an error path that still allows a user to sign more complex transactions while possibly eliding some information from the prompts is preferable to a hard error.

[jleni]

@neithanmo Can we document here the limits of the latest release?
I think we can then close this issue

[jleni]

@kantai @kyranjamie Can we close this?
I think the current limit has been acceptable in practice, right?

[neithanmo]

We do not have any limit here regarding the list, other than the number of the nested lists it may contain..that limit is 3 at the moment, but it can be increased if needed..