Have whenceforce() require the -x option to check the execute bit

This renders the behaviour of whenceforth() almost equivalent to type -P
in the absence of the -x option, the exception being that whenceforth()
never consults the hash table.

Signed-off-by: Kerin Millar <kfm@plushkava.net>

2 files changed, 60 insertions, 29 deletions

diff --git a/functions.sh b/functions.sh
index 367c4a3..4f6c0a0 100644
--- a/functions.sh
+++ b/functions.sh
@@ -565,23 +565,37 @@ warn()
 }
 
 #
-# Considers the first parameter as the potential name of an executable regular
-# file before attempting to locate it. If not specified as an absolute pathname,
-# a PATH search shall be performed in accordance with the Environment Variables
-# section of the Base Definitions. If an executable is found, its path shall be
-# printed. Otherwise, the return value shall be 1. This function is intended as
-# an alternative to type -P in bash. That is, it is useful for determining the
+# Considers the first parameter as a command name before trying to locate it as
+# a regular file. If not specified as an absolute pathname, a PATH search shall
+# be performed in accordance with the Environment Variables section of the Base
+# Definitions. If a file is found, its path shall be printed. Otherwise, the
+# return value shall be 1. If the -x option is specified then the file must
+# also be executable by the present user in order to be matched. This function
+# serves as an alternative to type -P in bash. It is useful for determining the
 # existence and location of an external utility without potentially matching
 # against aliases, builtins and functions (as command -v can).
 #
 whenceforth()
 (
-	local bin path prefix
+	local bin executable opt path prefix
+
+	executable=
+	while getopts :x opt; do
+		case ${opt} in
+			x)
+				executable=1
+				;;
+			'?')
+				_warn_for_args whenceforth "-${OPTARG}"
+				return 1
+		esac
+	done
+	shift "$(( OPTIND - 1 ))"
 
 	case $1 in
 		/*)
 			# Absolute command paths must be directly checked.
-			[ -f "$1" ] && [ -x "$1" ] && bin=$1
+			test -f "$1" && test ${executable:+-x} "$1" && bin=$1
 			;;
 		*)
 			# Relative command paths must be searched for in PATH.
@@ -603,7 +617,7 @@ whenceforth()
 					*)
 						bin=${prefix:-.}/$1
 				esac
-				[ -f "${bin}" ] && [ -x "${bin}" ] && break
+				test -f "${bin}" && test ${executable:+-x} "${bin}" && break
 			done
 	esac \
 	&& printf '%s\n' "${bin}"
diff --git a/test-functions b/test-functions
index 736836b..68e73eb 100755
--- a/test-functions
+++ b/test-functions
@@ -508,24 +508,40 @@ test_hr() {
 }
 
 test_whenceforth() {
-	set -- \
-		ge  1  PATH                        N/A                       \
-		ge  1  PATH                        .                         \
-		ge  1  PATH                        rather-unlikely-to-exist  \
-		ge  1  PATH                        /var/empty                \
-		ge  1  PATH                        /var/empty/nofile         \
-		eq  0  PATH                        /bin/sh                   \
-		eq  0  PATH                        sh                        \
-		eq  0  ''                          newer/file                \
-		eq  0  .                           newer/file                \
-		eq  0  :/var/empty/x               newer/file                \
-		eq  0  /var/empty/x:               newer/file                \
-		eq  0  /var/empty/x::/var/empty/y  newer/file                \
-		ge  1  ''                          older/file                \
-		ge  1  .                           older/file                \
-		ge  1  :/var/empty/x               older/file                \
-		ge  1  /var/empty/x:               older/file                \
-		ge  1  /var/empty/x::/var/empty/y  older/file
+	set  --  \
+		ge  1  PATH                        N/A                N/A                \
+		ge  1  PATH                        .                  N/A                \
+		ge  1  PATH                        unlikely-to-exist  N/A                \
+		ge  1  PATH                        /var/empty         N/A                \
+		ge  1  PATH                        /var/empty/nofile  N/A                \
+		eq  0  PATH                        /bin/sh            N/A                \
+		eq  0  PATH                        sh                 N/A                \
+		ge  1  PATH                        -x                 .                  \
+		ge  1  PATH                        -x                 unlikely-to-exist  \
+		ge  1  PATH                        -x                 /var/empty         \
+		ge  1  PATH                        -x                 /var/empty/nofile  \
+		eq  0  PATH                        -x                 /bin/sh            \
+		eq  0  PATH                        -x                 sh                 \
+		eq  0  ''                          -x                 newer/file         \
+		eq  0  .                           -x                 newer/file         \
+		eq  0  :/var/empty/x               -x                 newer/file         \
+		eq  0  /var/empty/x:               -x                 newer/file         \
+		eq  0  /var/empty/x::/var/empty/y  -x                 newer/file         \
+		eq  0  ''                          -x                 newer/file         \
+		eq  0  .                           -x                 newer/file         \
+		eq  0  :/var/empty/x               -x                 newer/file         \
+		eq  0  /var/empty/x:               -x                 newer/file         \
+		eq  0  /var/empty/x::/var/empty/y  -x                 newer/file         \
+		eq  0  ''                          older/file         N/A                \
+		eq  0  .                           older/file         N/A                \
+		eq  0  :/var/empty/x               older/file         N/A                \
+		eq  0  /var/empty/x:               older/file         N/A                \
+		eq  0  /var/empty/x::/var/empty/y  older/file         N/A                \
+		ge  1  ''                          -x                 older/file         \
+		ge  1  .                           -x                 older/file         \
+		ge  1  :/var/empty/x               -x                 older/file         \
+		ge  1  /var/empty/x:               -x                 older/file         \
+		ge  1  /var/empty/x::/var/empty/y  -x                 older/file
 
 	chmod +x newer/file
 
@@ -533,15 +549,16 @@ test_whenceforth() {
 		shift
 		path=$1
 		shift
-		test_description="whenceforth $(quote_args "$@")"
 		if [ "${path}" = PATH ]; then
+			test_description="whenceforth $(quote_args "$@")"
 			whenceforth "$@" >/dev/null
 		else
+			test_description="PATH=${path} whenceforth $(quote_args "$@")"
 			PATH=${path} whenceforth "$@" >/dev/null
 		fi
 	}
 
-	iterate_tests 4 "$@"
+	iterate_tests 5 "$@"
 }
 
 test_get_nprocs() {