app-alternatives/awk: add 4 (warning for mawk)

Add one-off warning if using mawk, as suggested by kerframil.

Signed-off-by: Sam James <sam@gentoo.org>

1 files changed, 95 insertions, 0 deletions

diff --git a/app-alternatives/awk/awk-4.ebuild b/app-alternatives/awk/awk-4.ebuild
new file mode 100644
index 000000000000..127157897532
--- /dev/null
+++ b/app-alternatives/awk/awk-4.ebuild
@@ -0,0 +1,95 @@
+# Copyright 2022 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+ALTERNATIVES=(
+	gawk:sys-apps/gawk
+	busybox:sys-apps/busybox
+	mawk:sys-apps/mawk
+	nawk:sys-apps/nawk
+)
+
+inherit app-alternatives
+
+DESCRIPTION="/bin/awk and /usr/bin/awk symlinks"
+KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~x64-cygwin ~amd64-linux ~x86-linux ~ppc-macos ~x64-macos ~sparc-solaris ~sparc64-solaris ~x64-solaris ~x86-solaris"
+IUSE="split-usr"
+
+RDEPEND="
+	!app-eselect/eselect-awk
+"
+
+src_install() {
+	local alt=$(get_alternative)
+	local root_prefix=
+	use split-usr && root_prefix=../../bin/
+
+	# We could consider setting AWK=... like we do for yacc & lex,
+	# but it would need some testing with a fair amount of packages first,
+	# as autoconf prefers gawk.
+	case ${alt} in
+		busybox)
+			dosym "${root_prefix}busybox" /usr/bin/awk
+			;;
+		*)
+			dosym "${alt}" /usr/bin/awk
+			;;
+	esac
+
+	newman - awk.1 <<<".so ${alt}.1"
+
+	if use split-usr; then
+		dosym ../usr/bin/awk /bin/awk
+	fi
+}
+
+pkg_preinst() {
+	HAD_MAWK=0
+
+	has_version "app-alternatives/awk[mawk]" && HAD_MAWK=1
+
+	local v
+	for v in ${REPLACING_VERSIONS}; do
+		if ver_test "${v}" -lt 4; then
+			SHOW_MAWK_WARNING=1
+		fi
+
+		# if we are upgrading from a new enough version, leftover manpage
+		# symlink cleanup was done already
+		if ver_test "${v}" -ge 3; then
+			return
+		fi
+	done
+
+	# otherwise, remove leftover files/symlinks created by eselect-awk (sic!)
+	shopt -s nullglob
+	local files=( "${EROOT}"/usr/share/man/man1/awk.1* )
+	shopt -u nullglob
+
+	if [[ ${files[@]} ]]; then
+		einfo "Cleaning up leftover manpage symlinks from eselect-awk ..."
+		rm -v "${files[@]}" || die
+	fi
+}
+
+pkg_postinst() {
+	# Show the warning on new installs if using mawk, or older installs
+	# if upgrading from < app-alternatives/awk-4[mawk].
+	if [[ -z ${REPLACING_VERSIONS} || ${SHOW_MAWK_WARNING} -eq 1 || ${HAD_MAWK} -eq 0 ]] && use mawk; then
+		ewarn "mawk (incompletely) implements  awk, as it was defined by the now-obsolete"
+		ewarn "POSIX 1003.2 (draft 11.3) specification. It does not fully implement the standard"
+		ewarn "extended regular expression syntax and there are other known issues pertaining to POSIX conformance."
+	fi
+}
+
+pkg_postrm() {
+	# make sure we don't leave the user without the symlinks, since
+	# they've not been owned by any other package
+	if [[ ! -h ${EROOT}/usr/bin/awk ]]; then
+		ln -s gawk "${EROOT}/usr/bin/awk" || die
+	fi
+	if [[ ! -h ${EROOT}/bin/awk ]]; then
+		ln -s ../usr/bin/awk "${EROOT}/bin/awk" || die
+	fi
+}