why does PyCoq opam pin a package before doing the strace of an opam reinstall?

[brando90]

I noticed that PyCoq does:

    if ((not coq_proj_path is None) and
            not opam_pin_package(coq_proj, coq_proj_path, coq_serapi, coq_serapi_pin, compiler)):

before it tries to strace the opam reinstall ... coq_pkg of the coq pkg in question. Is the opam pin really necessary before? How can we remove that depedency? Would it work if the package was built with make clean -C ...?