unable to use non-inlineable library in tests directly

[Karrq]

Component

Forge

Have you ensured that all of these are up to date?

• Foundry
• Foundryup

What version of Foundry are you on?

7f93bae

What version of Foundryup are you on?

No response

What command(s) is the bug in?

forge test

Operating System

macOS (Apple Silicon)

System Specifications

M3 Max, 64GB

Describe the bug

When using a library directly in a test script, execution reverts, and we also get an error that the bytecode at the given address (done thru deletegatecall) is empty.

Here's a repro example:
direct_use.patch

[Karrq]

When using a non-inlineable library, the compiler will insert a reference that is eventually replaced by an on-chain address before the bytecode can be used (for tests or deployment or whatnot).

The address computation is different between EVM and EraVM, therefore contracts compiled for EVM will make use of a different address than what is in EraVM.

As scripts & tests are run in EVM always (by design), the references that those contracts hold for libraries will be those of EVM, not EraVM. This, combined with our system intercepting the delegatecall and redirecting it to be done in EraVM is what causes the issue, in short:

1. Script/Test is calling the lib at EVM address
2. Equivalent lib in EraVM is not at same address

When zksolc linking was implemented, we decided to not force lib deployment on EraVM to have the same address as the EVM counterpart, as those addresses wouldn't match what is ultimately deployed on-chain, which would also mean that we wouldn't support usage of predeployed libraries.

One solution for this issue would be to keep a mapping between EVM and EraVM deployed library address, that way the system can use that mapping to execute the correct library code across VM boundaries.
Considering that the deploy_library implementation for ZKSync strategy also invokes the EVM's implementation, we can already populate the mapping at that point, and reference it later during the execution of the test code.

Alternative solutions are possible but haven't been researched yet