commit e33b5f976eb631d64485474683cea67a7cf6f712
from: Thomas Adam <thomas@xteddy.org>
date: Sun Mar 05 23:45:37 2023 UTC

portable: regress: improve date wrapper

When looking for a suitable date wrapper, don't use the platform name,
and rather use date(1)'s own parsing to choose BSD date, or gdate (GNU).

Additionally, only declare the date() wrapper once.

From Christian "naddy" Weisgerber

commit - 8fedfb3cc9c6c88a5105f3926595d3807da6922d
commit + e33b5f976eb631d64485474683cea67a7cf6f712
blob - ceda4608d69d1238f584e5d362eb9471e406fb2e
blob + 745539b43da693829d69925c94761edf2731751d
--- regress/cmdline/common.sh
+++ regress/cmdline/common.sh
@@ -40,29 +40,34 @@ export MALLOC_OPTIONS=S
 # commands are used.
 [ -z "$PLATFORM" -a "$(uname)" = "Linux" ] && PLATFORM="linux"
 
-[ "$(date -u -r 86400 +%F 2>/dev/null)" = 1970-01-02 ] || date()
-{
-	DATECMD="date"
-	[ "$PLATFORM" != "linux" ] && {
-		command -v "gdate" >/dev/null 2>&1 && {
-			DATECMD="gdate"
-		} || {
-			echo "Couldn't find gdate is GNU coreutils installed?"
-		}
-	}
-
-	local flag r u
-	while getopts r:u flag; do
-		case $flag in
-		r)	r=$OPTARG ;;
-		u)	u=-u ;;
-		?)	exit 1 ;;
-		esac
+if [ "$(date -u -r 86400 +%F 2>/dev/null)" != 1970-01-02 ]; then
+	DATECMD=
+	for p in date gdate; do
+		if [ "$($p -u -d @86400 +%F 2>/dev/null)" = 1970-01-02 ]; then
+			DATECMD=$p
+			break
+		fi
 	done
-	shift $((OPTIND - 1))
-	command "$DATECMD" $u ${r+-d"@$r"} "$@"
-}
+	if [ -z "$DATECMD" ]; then
+		echo "Couldn't find gdate, is GNU coreutils installed?" >&2
+		exit 1
+	fi
 
+	date()
+	{
+		local flag r u
+		while getopts r:u flag; do
+			case $flag in
+			r)	r=$OPTARG ;;
+			u)	u=-u ;;
+			?)	exit 1 ;;
+			esac
+		done
+		shift $((OPTIND - 1))
+		command "$DATECMD" $u ${r+-d"@$r"} "$@"
+	}
+fi
+
 sed()
 {
 	SEDCMD="sed"