Add block number for external contract events

[remybar]

Description

To ease external contract indexing at Torii level, ExternalContractRegistered and ExternalContractUpgraded events must contain the block number to use for indexing.

At sozo level, there are 2 kinds of external contracts: the ones directly deployed and so managed by sozo (called sozo-managed), and the ones deployed outside of sozo (called self-managed).

For sozo-managed external contracts:

• by default, the block number of the deploy transaction is used to register the contract into the world, but it can be overriden in dojo_dev.toml. A ExternalContractRegistered event is emitted with this block number.
• If the contract changes (its class_hash changes), it will be upgraded but, as its address stays the same, the contract registration at world level does not change.
• If the configured block_number in dojo_dev.toml changes, the contract registration at world level will be updated with the new block number (i.e a ExternalContractUpgraded event will be emitted).

For self-managed external contracts:

• if the block number is not provided in the dojo_dev.toml, 0 is used by default.
• the first time the contract is detected in the dojo_dev.toml file, it is registered into the world with the configured block number (0 by default),
• if the configured block number changes, the contract registration at world level is updated with the new block number (i.e a ExternalContractUpgraded event will be emitted).

Tests

• Yes
• No, because they aren't needed
• No, because I need help

Added to documentation?

• README.md
• Dojo Book
• [] No documentation needed

Checklist

• I've formatted my code (scripts/rust_fmt.sh, scripts/cairo_fmt.sh)
• I've linted my code (scripts/clippy.sh, scripts/docs.sh)
• I've commented my code
• I've requested a review after addressing the comments

[glihm]

The goal of the block number is that when Torii detects this event, it knows at which block this contract must be indexed from.

In the current implementation, we are actually using the current block, which may not correspond to the block the user wants to setup the indexing from.

This must be an argument of the register external contract function. In case that the external contract is not a token, which may not be indexed by Torii, the use can simply use 0.
Otherwise, the user can provide the block at which the token has been deployed (which is not the get_block_number()).

Does it make sense to you too?

cc @MartianGreed this is how I understood it at least.

[MartianGreed]

That totally makes sense !

[remybar]

Hum ok, but external contracts are deployed by sozo so how the user knows/provides the block number to use for indexing to be able to pass it to the register_external_contract entry point ? Because registering is done just after having deployed the contract.
It looks like more an indexer configuration (so at Torii level) than an information that should be provided when registering the external contract 🤔
But if you still think that this information has to be present in the ExternalContractRegistered event, we can provide this block number through the dojo_dev.toml file for example, and then pass it to the register entry point.
Tell me WDYT about that 😉

[glihm]

The user can know the block when it's a token that already exists in the network for instance. Let's say $LORD for instance, one may just want to register this token in the world to ease the dns usage to refer to this token instead of hardcoding addresses.

It is definitely an indexer configuration. However the goal here is to give the whole context to the automatic indexer Torii, to avoid having to edit configurations for each new token.
In a marketplace example, having to restart Torii by adding a new token address would make it unmanageable.

With this strategy of exposing the block number during the registration, then a marketplace could have Torii automatically adding some tokens to the indexing list without restart or human intervention in the config.

But if you still think that this information has to be present in the ExternalContractRegistered event, we can provide this block number through the dojo_dev.toml file for example, and then pass it to the register entry point.

Yes this sounds the right approach. I guess that when Sozo is deploying the external contract, then the block could be automatically taken.
However, we should also be able to pass the block for contracts not deployed by Sozo.

Not sure the migration has this info at the moment, we may need to add this context for Sozo when deployments are done.

[remybar]

Thanks for this detailed feedback 👍

I've updated the PR (description + code) accordingly but I still have to test all the corner cases.

[glihm]

Thank you @remybar for the work here and the addition of this block number parameter. 👍

Was wondering if the block number should be an option instead of u64. Since in some cases, the registration of the contract may not be coupled to indexing.

But we may stay with that for now, and we will see with usage in the marketplace. 🫡