Build Fails Due to “Failed to Resolve Version 1 of Yarn” Without Any Config Changes

Context

Railway deploys via Railpack suddenly fail with Failed to resolve version 1 of yarn / Failed to resolve version 1.22.22 even though nothing changed in the project, yarn 1.x detected via Corepack/mise, then version resolution fails.

Verified resolution

Maintainer iloveitaly (maintains railpack): this was platform-side, the mise yarn backend (asdf) was broken/corrupted for a period of time; Railpack later moved to a different mise backend via PR #216, but the asdf backend had already been fixed, so builds recovered on their own (deploy again and it should be fixed). Workarounds that reporters used meanwhile: pin the builder to NIXPACKS in railway.json, or switch the service to a Dockerfile that installs yarn directly (npm i -g yarn@1.22.22).

In gh:railwayapp/railpack#210 (https://github.com/railwayapp/railpack/issues/210), the question was: Railway deploys via Railpack suddenly fail with Failed to resolve version 1 of yarn / Failed to resolve version 1.22.22 even though nothing changed in the project, yarn 1.x detected via Corepack/mise, then version resolution fails. The verified resolution: Maintainer iloveitaly (maintains railpack): this was platform-side, the mise yarn backend (asdf) was broken/corrupted for a period of time; Railpack later moved to a different mise backend via PR #216, but the asdf backend had already been fixed, so builds recovered on their own (deploy again and it should be fixed). Workarounds that reporters used meanwhile: pin the builder to NIXPACKS in railway.json, or switch the service to a Dockerfile that installs yarn directly (npm i -g yarn@1.22.22).