Re: [PATCH] contrib: Cleanup downloaded archives in download_prerequisites

(Resending to the list - my previous reply went to Alexander only
   by mistake.)

Hi Alexander,

I'm not aware of any discussion behind dropping the cleanup step -
from what I can tell it was incidental.

download_prerequisites was introduced in 2010 (commit 69baf0a) and
explicitly removed the downloaded archives at the end:

    rm $MPFR.tar.bz2 $GMP.tar.bz2 $MPC.tar.gz || exit 1

That stayed in place for about three years.

In 2013, commit a8db599 ("download_prerequisites: Download isl and
cloog conditionally") dropped that line while adding conditional
isl/cloog handling. The commit message is entirely about making
isl/cloog optional and says nothing about archive cleanup, so the
removal looks like an unrelated side effect rather than a deliberate
change.

So my patch is restoring the 2010-2013 behavior rather than
introducing something new. --save-archives/--no-save-archives is
there for people who want to keep the archives around (offline
rebuilds etc).

Separately: I noticed my patch has the same weakness the current
script already has - if extraction fails partway through, the target
directory is left non-empty, and the next run (without --force) treats
it as already extracted and silently skips it. The extraction step
only checks `[ -e "${directory}/${package}" ]`, so this isn't
new, but it's worth fixing while we're touching this area:

    [ -e "${directory}/${package}" ]                                          \
        || ( cd "${directory}" && $uncompress <"${ar}" | tar -xf - )          \
        || { rm -rf "${directory:?}/${package}"; die "Cannot extract package from ${ar}"; }

Can fold this into v2 or send separately, whichever you prefer.

Daniil