meson.eclass: MESON_AUTO_DEPEND support

Make it possible to use the meson eclass without it automatically adding
meson to DEPEND. Intended for cases where meson usage is conditional
(e.g. hidden behind a USE flag).

This is a direct copy of the AUTOTOOLS_AUTO_DEPEND functionality &
implementation from autotools.eclass, including the guard for multiple
inheritance.

Closes: https://bugs.gentoo.org/626054
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
Signed-off-by: Mike Gilbert <floppym@gentoo.org>

diff --git a/eclass/meson.eclass b/eclass/meson.eclass
index 5b63f0ef3a33ef905addab263efe26897708ca13..b339017f90178078ee23a3a14613164bc08c89c6 100644 (file)
--- a/eclass/meson.eclass
+++ b/eclass/meson.eclass
@@ -38,6 +38,16 @@ case ${EAPI:-0} in
        *) die "EAPI=${EAPI} is not supported" ;;
 esac
 
+if [[ ${__MESON_AUTO_DEPEND+set} == "set" ]] ; then
+       # See if we were included already, but someone changed the value
+       # of MESON_AUTO_DEPEND on us.  We could reload the entire
+       # eclass at that point, but that adds overhead, and it's trivial
+       # to re-order inherit in eclasses/ebuilds instead.  #409611
+       if [[ ${__MESON_AUTO_DEPEND} != ${MESON_AUTO_DEPEND} ]] ; then
+               die "MESON_AUTO_DEPEND changed value between inherits; please inherit meson.eclass first! ${__MESON_AUTO_DEPEND} -> ${MESON_AUTO_DEPEND}"
+       fi
+fi
+
 if [[ -z ${_MESON_ECLASS} ]]; then
 
 inherit ninja-utils python-utils-r1 toolchain-funcs
@@ -49,9 +59,20 @@ EXPORT_FUNCTIONS src_configure src_compile src_test src_install
 if [[ -z ${_MESON_ECLASS} ]]; then
 _MESON_ECLASS=1
 
-DEPEND=">=dev-util/meson-0.40.0
+MESON_DEPEND=">=dev-util/meson-0.40.0
        >=dev-util/ninja-1.7.2"
 
+# @ECLASS-VARIABLE: MESON_AUTO_DEPEND
+# @DESCRIPTION:
+# Set to 'no' to disable automatically adding to DEPEND.  This lets
+# ebuilds form conditional depends by using ${MESON_DEPEND} in
+# their own DEPEND string.
+: ${MESON_AUTO_DEPEND:=yes}
+if [[ ${MESON_AUTO_DEPEND} != "no" ]] ; then
+       DEPEND=${MESON_DEPEND}
+fi
+__MESON_AUTO_DEPEND=${MESON_AUTO_DEPEND} # See top of eclass
+
 # @ECLASS-VARIABLE: BUILD_DIR
 # @DEFAULT_UNSET
 # @DESCRIPTION: