Raise warning if path specified in forge build does not match and fallback is triggered

[dyedm1]

Component

Forge

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

• Foundry
• Foundryup

What version of Foundry are you on?

forge 0.2.0 (4817280 2024-11-12T00:20:42.760650000Z)

What command(s) is the bug in?

forge build

Operating System

macOS (Apple Silicon)

Describe the bug

forge build with the ./path/to/contract:contractName syntax appears to behave identically to contractName syntax, compiling the entire project and searching the output for the desired contract name.

e.g.:

• forge build ./path/to/contract compiles 15 files
• forge build ./path/to/contract:contractName compiles 132 files
• forge build contractName also compiles 132 files

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Perhaps as a result of the behavior described in the first part of this issue, the ./path/to/contract appears to be ignored entirely, with compilation succeeding even when ./path/to/contract does not contain contractName.

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PoC:

A.sol

pragma solidity ^0.8.0; 
contract B {}

C.sol

pragma solidity ^0.8.0; 
contract D {}

Results

• i. forge build ./A.sol compiles B ✅
• ii. forge build ./A.sol:B compiles both B and D ❌
• iii. forge build B compiles both B and D ✅
• iv. forge build ./A.sol:D succeeds and compiles both B and D ❌

Expected behavior

• ii. should only compile D if it is in the same file as A or somewhere in the inheritance tree (in other words, the same contracts should be compiled as the i. case)
• iv. should fail? If ii. is implemented correctly, then D wouldn't be anywhere in the compiler output

[grandizzy]

@dyedm1 thank you for your report. This behavior is not supported (and I don't think can be added either), how forge build [PATHS] works is to build specific paths / files and not contracts

  [PATHS]...
          Build source files from specified paths

as shown here https://book.getfoundry.sh/reference/cli/forge/build
If there's no match then it simply ignores given paths and falls back to regular forge build, hence your results
i. A.sol file exists and can be built
ii. ./A.sol:B file doesn't exist so execution is equivalent to forge build
iii. B file doesn't exist so execution is equivalent to forge build
iv. ./A.sol:D file doesn't exist so execution is equivalent to forge build

@zerosnacks pls comment, thanks!

[zerosnacks]

I agree, I think the way we should address this would be to raise a warning if the path is missed and a fallback is triggered informing the user that there was no match in their specified path.