COPY racket dist from docker img is insufficient

[ccfontes]

Error: huh, erased from the terminal buffer, but it was spurious as such: build/exec/index not found.

Offending code:

FROM racket/racket:8.8 AS racket

FROM idris2-chez AS idris2-racket
ONBUILD COPY --from=racket /usr/bin/raco /usr/bin/raco
ONBUILD COPY --from=racket /usr/bin/racket /usr/bin/racket
ONBUILD COPY --from=racket /usr/share/racket /usr/share/racket
ONBUILD COPY --from=racket /usr/lib/racket /usr/lib/racket

What works:

FROM racket/racket:8.8 AS racket

FROM idris2-chez AS idris2-racket
ONBUILD RUN apt-get update && apt-get install --yes racket

Now we know this will get us into trouble in prod right? So, let's try to find out what's missing.

[ccfontes]

Error:

#26 [stage-6 16/13] RUN pack --cg racket build function.ipkg
#26 40.88 /usr/bin/raco: Unrecognized command: exe