n/a

that is a dynamic variable that would only be available during runtime, it's not available to be referenced

does runtime include build time?

meaning accessible during build

nixpacks or Dockerfile?

dockerfile

then it would be available during the build as long as you do ARG RAILWAY_GIT_COMMIT_SHA

That worked perfectly

ARG RAILWAY_GIT_COMMIT_SHA

ENV RAILWAY_GIT_COMMIT_SHA=${RAILWAY_GIT_COMMIT_SHA}

then set another var with it

you don't need that ENV line

you're assigning the same variable to the same variable

Ah, you are right!