[Protocol Manager] ERC-4337 Requirements for Account Creation

[nlordell]

This issue is here to document some of my findings around 4337 requirements, specifically in the context of account creation.

In particular the section on un-staked entities mentions that:

the UserOp creates a new account using a staked factory contract, then the entity may also use storage associated with the sender

This refers to the fact that access to the account's associated storage is only permitted to be used by entities (including the account entity during validateUserOp) if the factory is staked. So a validateUserOp that makes use of some mapping(account => value) in a separate contract, while it would be generally be considered fair use, it requires staking for account creation.

In particular this means that:

• In general the idea presented by @mmv08 in [Protocol Manager] Evaluate Protocol support for ERC4337 #60 (comment) works (and fortunately, there are no downsides AFAICT, see Refactor Storage Access to be 4337 Compatible #128)
• The factory contract should be staked. @akshay-ap suggested we can create a "wrapper factory" that supports the required staking, without needing to modify the current factory and change existing Safe infrastructure.

Alternatively, it would be possible to try and work with bundlers directly to add exceptions for Safe (there is prior-art for this: alchemyplatform/rundler#231). Personally, I'm not a fan of this approach (it feels icky to go against the spec if it is possible to so and makes things dependent on specific bundler support).

References

1. Some more discussion can be found in Non-compliant Storage Access Restrictions alchemyplatform/rundler#480.