configure: require bash >= 4.1 at compile time

We've unofficially agreed to raise our minimum supported bash version to
4.1, and since added features that require it. Additionally, an earlier
commit adds a syntax check to the builds of scripts/ and contrib/ which
could conceivably fail with an earlier shell. Therefore, make this a
hard requirement of the build process.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>

1 files changed, 17 insertions, 1 deletions

diff --git a/configure.ac b/configure.ac
index d488bfaf..0e78c238 100644
--- a/configure.ac
+++ b/configure.ac
@@ -148,7 +148,23 @@ AC_PROG_AWK
 AC_PROG_CC_C99
 AC_PROG_INSTALL
 AC_CHECK_PROGS([PYTHON], [python2.7 python2.6 python2.5 python2 python], [false])
-AC_PATH_PROGS([BASH_SHELL], [bash bash4 bash3], [false])
+AC_PATH_PROGS([BASH_SHELL], [bash bash4], [false])
+
+AS_IF([test "x$BASH_SHELL" = "xfalse"],
+	AC_MSG_WARN([*** bash >= 4.1.0 is required for pacman scripts]),
+	[bash_version_major=`$BASH_SHELL -c 'echo "${BASH_VERSINFO[[0]]}"'`
+	bash_version_minor=`$BASH_SHELL -c 'echo "${BASH_VERSINFO[[1]]}"'`
+	ok=yes
+	if test "$bash_version_major" -lt 4; then
+		ok=no
+	fi
+	if test "$bash_version_major" -eq 4 && test "$bash_version_minor" -lt 1; then
+		ok=no
+	fi
+	if test "$ok" = "no"; then
+		AC_MSG_ERROR([*** bash >= 4.1.0 is required for pacman scripts])
+	fi
+	unset bash_version_major bash_version_minor ok])
 
 # find installed gettext
 AM_GNU_GETTEXT([external], [need-ngettext])