Cluster definition hash incorrect for empty addresses or signatures

[corverroos]

Problem to be solved

The current (and previous) versions of the charon definition (<=v1.4) calculates the incorrect SSZ hash for empty Bytes20 (eth addresses) and Bytes65 (k1 signatures).

BytesN type fields should ALWAYS be of length N. So an empty address should be 20 bytes of just 0s, similarly an empty signature should be 56 bytes of just 0s. Charon uses empty arrays instead which is incorrect.

This is causing an incompatibility with the launchpad, specifically the solo slow that includes empty operator addresses. The JS implementation is doing it correctly. That means the launchpad generated solo flow definitions are not compatible with charon v1.4.

We cannot however fix this in charon v1.4, since it would break any lock files out there with empty addresses or signatures, specifically lock files created by the create cluster cli.

The proper solution is to fix this in charon, so as part of the upcoming v1.5 that will be released as part of charon v0.14.

Proposed solution

If the launchpad needs to support solo flow with charon v0.13 (so cluster definition v1.4), then we either need to:

• fix this in charon now v1.4, thereby throwing v1.4 create cluster users under the bus (requiring them to use --no-verify).
• or better, the launchpad can implement a workaround to achieve the same "buggy" behavior for the solo flow (and fix it in their v1.5 later).

Charon v1.5 should however include the fix. Charon v1.3 must still be compatible with buggy logic.