smart-wallet: handle null slots better

[samsiegart]

Describe the bug

The dapps make use of makeImportContext from smart-wallet to unmarshal serialized objects from vstorage, as well marshal them back when submitting transactions to the smart wallet. However, this util function throws when it encounters a null slot, which occurs in some inter protocol vstorage query results, breaking the fromCapData function. To circumvent this, the dapps have been patching the util to allow null slots.

Design the Fix

There's a few ways that this could be handled:

• Incorporate the patch directly into smart-wallet
• Incorporate the patch in a modified form, such as behind a parameter that the dapps would use and the smart-wallet would not.
• Write a different makeImportContext function just for dapps and put it in ui-kit. I'm not sure about this approach because it would be ideal for the contract and UI to be on the same page when it comes to serialization.

cc @dckc and @turadg for input

[dckc]

Design the Fix

There's a few ways that this could be handled:

...

• Write a different makeImportContext function just for dapps and put it in ui-kit.

I'm leaning that way, since I think the current makeImportContext is not the way to go. In particular, I think when remotables are un-marshalled on the client side, they shouldn't know the board ID whence they came. The correspondence should be in a separate table.

My current thinking is in...

https://github.com/Agoric/agoric-sdk/blob/2d7a2c57b4228e0100bf3dfa70a2e3c34c9db7df/packages/inter-cli/src/lib/boardClient.js#L12

[ivanlei]

Agree on ui-kit approach.