#!/usr/bin/env bash
# Minimal stand-in for devtools' arch-meson.
#
# A number of Arch PKGBUILDs call arch-meson rather than meson directly. It
# ships in the `devtools` package, which is itself an Arch package -- so
# during a bootstrap it does not exist yet, and every PKGBUILD that uses it
# stops on "arch-meson: command not found".
#
# This reproduces the options devtools passes, which are what the PKGBUILDs
# assume: /usr prefix, plain buildtype so makepkg's CFLAGS are honoured
# verbatim, and no network access for subprojects.
#
# TWO OPTIONS BELOW ARE NOT IN REAL devtools, AND COPYING devtools VERBATIM
# IS THE BUG THEY FIX. On Arch these defaults are already right, so devtools
# has nothing to say. We run on Ubuntu, where meson answers differently.
#
# --libdir. meson's default (utils/universal.py, default_libdir):
#
#     if is_debianlike():                       # /etc/debian_version exists
#         dpkg-architecture -qDEB_HOST_MULTIARCH
#         return 'lib/' + archpath              # -> lib/s390x-linux-gnu
#
# So every arch-meson package installed into /usr/lib/s390x-linux-gnu while
# its PKGBUILD went on naming /usr/lib. Nothing complained: makepkg exited 0
# and the packages went into the repo with their libraries somewhere no Arch
# ld.so and no pkgconf will ever look. util-linux is where it finally shouted,
#
#     rm: cannot remove '.../pkg/util-linux/usr/lib/lib*.a*': No such file
#
# and even there the rm was the first victim, not the cause -- the
# `mv usr/lib/lib*.so*` two lines below would have shipped an EMPTY
# util-linux-libs. Measured before the fix: expat, lz4, pacman, pkgconf and
# zstd were already in repo/s390x carrying multiarch paths, libalpm.so.16
# among them.
#
# --libdir sits BEFORE "$@" so a PKGBUILD passing its own still wins: meson's
# argparse takes the last occurrence.
#
# python.platlibdir / python.purelibdir. The same divergence one layer up:
# meson's python module uses Debian's `deb_system` scheme and installs to
# /usr/lib/python3/dist-packages, which Arch's python does not read. The
# value is derived from the interpreter rather than hardcoded, because that
# is exactly how the PKGBUILDs derive theirs -- util-linux's package() moves
# `$(python -c 'sysconfig.get_paths()["stdlib"]')/site-packages`, so deriving
# it the same way makes the two agree by construction instead of by luck.
_pystdlib="$(python3 -c 'import sysconfig; print(sysconfig.get_paths()["stdlib"])')"
exec meson setup \
    --prefix        /usr \
    --libdir        lib \
    --libexecdir    lib \
    --sbindir       bin \
    --buildtype     plain \
    --auto-features enabled \
    --wrap-mode     nodownload \
    -D b_pie=true \
    -D python.bytecompile=1 \
    -D python.platlibdir="$_pystdlib/site-packages" \
    -D python.purelibdir="$_pystdlib/site-packages" \
    "$@"