Conflicting remappings (with and without "/src") lead to failed build in monorepo with multiple foundry.toml configs

[PaulRBerg]

Component

Forge

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

• Foundry
• Foundryup

What version of Foundry are you on?

v1.3.5-nightly

What version of Foundryup are you on?

v1.3.0

What command(s) is the bug in?

forge build

Operating System

macOS (Apple Silicon)

Describe the bug

Bug Report

When the user remaps forge-std/=../node_modules/forge-std/src/, but another dependency expects forge-std to be remapped WITHOUT the /src/ path, the build fails.

In my case, this happens when I use the openzeppelin-foundry-upgrades dependency alongside my remappings:

[profile.default]
  remappings = [
    "@chainlink/=../node_modules/@chainlink/",
    "@openzeppelin/=../node_modules/@openzeppelin/",
    "@prb/=../node_modules/@prb/",
    "@sablier/=../node_modules/@sablier/",
    "forge-std/=../node_modules/forge-std/",
    "solady/=../node_modules/solady/",
  ]

Error Log

Error: Compiler run failed:
Error (6275): Source "../node_modules/forge-std/Vm.sol" not found: File not found. Searched the following locations: "/home/runner/work/evm-monorepo/evm-monorepo/utils".
ParserError: Source "../node_modules/forge-std/Vm.sol" not found: File not found. Searched the following locations: "/home/runner/work/evm-monorepo/evm-monorepo/utils".
 --> ../node_modules/@openzeppelin/foundry-upgrades/src/Upgrades.sol:9:1:
  |
9 | import {Vm} from "forge-std/Vm.sol";
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Repro

1. Clone https://github.com/sablier-labs/evm-monorepo/tree/0f06c91b46b38f66c986780ac7736b61edcce0fb
2. Run bun install
3. cd utils
4. forge build

Related

Possibly related to #5447

[grandizzy]

please check https://getfoundry.sh/guides/project-setup/dependencies#remapping-conflicts most probably you need to map in their respective contexts

[grandizzy]

@PaulRBerg I am also not able to reproduce the issue

george@pop-os:~/work/foundry-issues/evm-monorepo/utils$ forge build
[⠒] Compiling...
[⠃] Compiling 152 files with Solc 0.8.29
[⠘] Solc 0.8.29 finished in 12.78s
Compiler run successful!
george@pop-os:~/work/foundry-issues/evm-monorepo/utils$ git log -1
commit 0f06c91b46b38f66c986780ac7736b61edcce0fb (HEAD)
Author: Paul Razvan Berg <prberg@proton.me>
Date:   Mon Sep 8 20:53:51 2025 -0400

    ci: build and cache
    
    refactor: rename to "foundry.toml"

do I miss any step here? thank you

[PaulRBerg]

@grandizzy did you cd utils before running forge build?

I am still able to reproduce the bug using forge v1.3.5-nightly

I'll take a look at that remapping conflicts reference you shared, thanks!

[grandizzy]

@grandizzy did you cd utils before running forge build?

I am still able to reproduce the bug using forge v1.3.5-nightly

I'll take a look at that remapping conflicts reference you shared, thanks!

yeah, see command above is performed from evm-monorepo/utils 🤔

[PaulRBerg]

Strange. You using Bun v1.2.21? and same version of Forge?

I cloned the repo in a new directory and I was still able to reproduce.

[grandizzy]

Strange. You using Bun v1.2.21? and same version of Forge?

I cloned the repo in a new directory and I was still able to reproduce.

hm, I have bun 1.1.25, will update and retry.

[grandizzy]

yeah, manage to repro, the thing is that remappings doesn't recurse outside of foundry project but always caps at proj root, hence "openzeppelin-foundry-upgrades/=../node_modules/@openzeppelin/foundry-upgrades/", it looks only inside proj/home/george/work/foundry-issues/evm-monorepo/utils

Source "../node_modules/forge-std/Vm.sol" not found: File not found. Searched the following locations: "/home/george/work/foundry-issues/evm-monorepo/utils"