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

TL;DR

Fix: 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).

The error

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.

Fix

1. 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).
2. 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).

Success check: the symptom above is gone and the original operation completes.

When to use

• You hit this exact symptom in railpack.
• You want the verified fix without digging through the thread.

When not to use

• A different error in railpack, even a similar-looking one.
• General railpack setup or credential questions.

Compatibility

• Railpack (railwayapp/railpack) Reported against version 1.

Variant phrasings

• How to fix "build Fails Due to “Failed to Resolve Version 1 of Yarn” Without Any Config Changes" in railpack
• railpack: build Fails Due to “Failed to Resolve Version 1 of Yarn” Without Any Config Changes
• build Fails Due to “problem to Resolve Version 1 of Yarn” Without Any Config Changes

Source

• https://github.com/railwayapp/railpack/issues/210

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).