feat: don't request Solc JSON AST unless absolutely necessary

[DaniPopes]

The Solc JSON AST output is very expensive to both serialize on the compiler's side, and deserialize on our side due to its very nested nature and generally big size.

This is especially noticeable on hot starts thanks to less time spent deserializing all the already-compiled artifacts. This is applicable to all commands that require a built project.

Adds the ast = <bool> config and --ast flag to build args to optionally include the AST in the artifacts.

We currently use the AST in:

• coverage
• flatten
• inline test config (NatSpec)

coverage and flatten have been updated to override the ast config.
test has not been updated for inline test config since it currently does not work, and all tests pass without it. It will have to be rewritten using solang_parser or something else.

Results

Note that I'm using the debug profile to build forge, but this won't matter much as most of the time is spent in solc anyway.

Default forge init project:

Solmate:

sablier/v2-core:

• out/ size before: 144Mb
• out/ size after: 106Mb
• profile before: https://share.firefox.dev/42KyHyM
• profile after: https://share.firefox.dev/3T2RrpQ
  

ethereum-optimism/optimism packages/contracts-bedrock

[mattsse]

does this affect the regular forge build artifacts?

we added metadata because this is apparently used by some tools

that's not part of metadata, so I think we can do that, but not entirely sure

[mattsse]

I'd be fine with that.

we should check with slither first if they're relying on this in the artifacts file

[onbjerg]

some external tools rely on this, so i'd add a flag to forge build to get this back

[mds1]

cc @0xalpharush for thoughts on how this affects slither

[gakonst]

Can we get a comparison for release mode compilation time improvements due to this on a large repo? e.g. Optimism contracts

[DaniPopes]

Can we get a comparison for release mode compilation time improvements due to this on a large repo? e.g. Optimism contracts

@gakonst
The overwhelming majority of the time is spent in solc so release mode on our side won't do much here.

It's 2-3% faster on clean builds, up to 2-3x for sablier/v2-core (absolute time save of about 2.5s for both). Note that time saved is proportional to amount of total artifacts.
Same for optimism contracts (updated description).

[0xalpharush]

I ran foundryup -b dani/drop-ast and it does make slither not work since the ASTs are missing. I think it is fine to drop from forge build but I'd prefer forge build --build-info (the hardhat artifact style) to be backwards compatible ofc. Otherwise, we'd have to cut a release and handle the case where people are not on this version of foundry yet