forge flatten sort contracts alphabetically

[sakulstra]

Component

Forge

Describe the feature you would like

We rely on flatten quite heavily to diff code.
One huge pain point with this is that flattening two versions of a contract can result in dramatically different code as import order might have changed.

Therefore it would be a huge help/improvement if flatten would sort contacts alphabetically, either as default or when passing a flag.

Additional context

No response

[grandizzy]

per foundry compilers comment

/// We can't just sort files alphabetically as it might break compilation, because Solidity
/// does not allow base class definitions to appear after derived contract
/// definitions.
///
/// Instead, we sort files by the number of their dependencies (imports of any depth) in ascending
/// order. If files have the same number of dependencies, we sort them alphabetically.
/// Target file is always placed last.

simple test yields solc failure with Error (2449): Definition of base has to precede definition of derived contract

@klkvr could you please chime in?

[sakulstra]

@grandizzy interesting, i was not aware.

For us this would still be insanely useful 😅 - we don't actually want to build/test or deploy the flattened code. We just want to compare it.
The realworld problem we have is for example here vs here.

In the first Address comes first, in the second Initializable comes first. Both i think don't have dependencies.

---

Perhaps this overall approach is a bit suboptimal and there might be better ways to do this?
Would be curious on your opinions, I guess contract diffing could be a quite useful feature on foundry itself as i guess everyone working with proxies would be interested in this.

[klkvr]

@sakulstra this was initially addressed in scope of foundry-rs/compilers#52 to resolve #6539

Sorting contracs alphabetically is not feasible because of the base has to precede definition of derived contract error. When working on this I was mostly optimizing for diff readability which I think is good enough now as order of files is pretty much deterministic as long as imported fileds not change.

The realworld problem we have is for example here vs here.

In the first Address comes first, in the second Initializable comes first. Both i think don't have dependencies.

This is happening because in the second file, Initializable.sol is coming from lib/aave-v3-origin/.. which is lexicographically higher than Address.sol path

[sakulstra]

This is happening because in the second file, Initializable.sol is coming from lib/aave-v3-origin/.. which is lexicographically higher than Address.sol path

Sorry, i don't see it 😅

How is Initializable lexicographically higher than Address? Or is the path considered for the sorting... which would be weird, no?
As in this case changing from e.g. submodules to soldeer or npm would completely change the output i guess?

[klkvr]

Or is the path considered for the sorting... which would be weird, no?

yeah path is considered right now

As in this case changing from e.g. submodules to soldeer or npm would completely change the output i guess?

yeah tbh I'd say this is an edge case I just didn't consider at the time :) I guess we can use path as secondary sorting key, should be fixed in foundry-rs/compilers#247