tests: remove use of unprotected 'set'

* cfg.mk (sc_prohibit_bare_set): A new syntax check to
ensure we protect use of set with '--', so that args
beginning with '-' are not interpreted as options,
and if no args are present, all existing args are cleared.
* tests/cp/symlink-slash.sh: Add -- to unprotected use of set.
* tests/ls/ls-time.sh: Likewise.
* tests/ls/symlink-slash.sh: Likewise.
* tests/mkdir/perm.sh: Likewise.
* tests/mkdir/selinux.sh: Likewise.
* tests/mkdir/smack-no-root.sh: Likewise.
* tests/mkdir/smack-root.sh: Likewise.
* tests/mv/part-hardlink.sh: Likewise.
* tests/nice/nice.sh: Likewise.
* tests/stty/stty-row-col.sh: Likewise.

cfg.mk

@@ -498,6 +498,12 @@ sc_prohibit_NULL:
 	halt='use nullptr instead'					\
 	  $(_sc_search_regexp)
 
+sc_prohibit_bare_set:
+	@prohibit='^ *set [`$$]'					\
+	in_vc_files='\.sh$$'						\
+	halt='use set -- $$args instead of set $$args'			\
+	  $(_sc_search_regexp)
+
 # Don't use "indent-tabs-mode: nil" anymore.  No longer needed.
 sc_prohibit_emacs__indent_tabs_mode__setting:
 	@prohibit='^( *[*#] *)?indent-tabs-mode:'			\

tests/cp/symlink-slash.sh

@@ -24,7 +24,7 @@ mkdir dir || framework_failure_
 ln -s dir symlink || framework_failure_
 
 cp -dR symlink/ s || fail=1
-set $(ls -l s)
+set -- $(ls -l s)
 
 # Prior to fileutils-4.0q, the following would have output ...'s -> dir'
 # because the trailing slash was removed unconditionally (now you have to

tests/ls/ls-time.sh

@@ -38,7 +38,7 @@ touch -m -d "$t1" c || framework_failure_
 
 # Check default name sorting works
 for def_sort in '' '--sort=name' '-U --sort=name' '-t --sort=name'; do
-  set $(ls $def_sort a B c)
+  set -- $(ls $def_sort a B c)
   test "$*" = 'B a c' || fail=1
 done
 
@@ -53,9 +53,9 @@ touch -a -d "$u1" a || framework_failure_
 
 
 # A has ctime more recent than C.
-set $(ls -t -c a c)
+set -- $(ls -t -c a c)
 test "$*" = 'a c' || fail=1
-set $(ls -c a c)  # Not specified by POSIX
+set -- $(ls -c a c)  # Not specified by POSIX
 test "$*" = 'a c' || fail=1
 
 # Sleep so long in an attempt to avoid spurious failures
@@ -101,20 +101,20 @@ EOF
   ;;
 esac
 
-set $(ls -ut a B c)
+set -- $(ls -ut a B c)
 test "$*" = 'c B a' || fail=1
-set $(ls -u a B c)  # not specified by POSIX
+set -- $(ls -u a B c)  # not specified by POSIX
 test "$*" = 'c B a' || fail=1
 test $fail = 1 && ls -l --full-time --time=access a B c
 
-set $(ls -t a B c)
+set -- $(ls -t a B c)
 test "$*" = 'a B c' || fail=1
-set $(ls --time=mtime a B c)
+set -- $(ls --time=mtime a B c)
 test "$*" = 'a B c' || fail=1
 test $fail = 1 && ls -l --full-time a B c
 
 # Now, C should have ctime more recent than A.
-set $(ls -ct a c)
+set -- $(ls -ct a c)
 if test "$*" = 'c a'; then
   : ok
 else

tests/ls/symlink-slash.sh

@@ -22,7 +22,7 @@ print_ver_ ls
 mkdir dir || framework_failure_
 ln -s dir symlink || framework_failure_
 
-set $(ls -l symlink/)
+set -- $(ls -l symlink/)
 
 # Prior to fileutils-4.0k, the following would have output '... symlink -> dir'.
 test "$*" = 'total 0' && : || fail=1

tests/mkdir/perm.sh

@@ -47,7 +47,7 @@ for p in empty -p; do
 
   old_IFS=$IFS
   IFS=':'
-  set $colon_tests
+  set -- $colon_tests
   IFS=$old_IFS
 
   while :; do

tests/mkdir/selinux.sh

@@ -33,7 +33,7 @@ for cmd_w_arg in 'mkdir dir' 'mknod b p' 'mkfifo f'; do
   # In OpenBSD's /bin/sh, mknod is a shell built-in.
   # Running via "env" ensures we run our program and not the built-in.
   env -- $cmd_w_arg --context=$c 2> out && fail=1
-  set $cmd_w_arg; cmd=$1
+  set -- $cmd_w_arg; cmd=$1
   echo "$cmd: $msg" > exp || framework_failure_
 
   # Some systems fail with ENOTSUP, EINVAL, ENOENT, or even

tests/mkdir/smack-no-root.sh

@@ -28,7 +28,7 @@ msg="failed to set default file creation context to '$c':"
 
 for cmd in 'mkdir dir' 'mknod b p' 'mkfifo f'; do
   $cmd --context="$c" 2> out && fail=1
-  set $cmd
+  set -- $cmd
   echo "$1: $msg" > exp || framework_failure_
 
   sed -e 's/ Operation not permitted$//' out > k || framework_failure_

tests/mkdir/smack-root.sh

@@ -28,7 +28,7 @@ c=arbitrary-smack-label
 
 for cmd in 'mkdir dir' 'mknod b p' 'mkfifo f'; do
   $cmd --context="$c" || { fail=1; continue; }
-  set $cmd
+  set -- $cmd
   ls -dZ $2 > out || fail=1
   test "$(cut -f1 -d' ' out)" = "$c" || { cat out; fail=1; }
 done

tests/mv/part-hardlink.sh

@@ -35,9 +35,9 @@ mv f g "$other_partition_tmpdir" || fail=1
 mv a b "$other_partition_tmpdir" || fail=1
 
 cd "$other_partition_tmpdir"
-set $(ls -Ci f g)
+set -- $(ls -Ci f g)
 test $1 = $3 || fail=1
-set $(ls -Ci a/1 b/1)
+set -- $(ls -Ci a/1 b/1)
 test $1 = $3 || fail=1
 
 Exit $fail

tests/nice/nice.sh

@@ -42,7 +42,7 @@ tests='
 19 --1:-12 12
 NA LAST NA
 '
-set $tests
+set -- $tests
 
 # Require that this test be run at 'nice' level 0.
 niceness=$(nice)

tests/stty/stty-row-col.sh

@@ -53,7 +53,7 @@ tests='
 11 rows_036 30_80
 NA LAST NA
 '
-set $tests
+set -- $tests
 
 saved_size=$(stty size) && test -n "$saved_size" \
   || skip_ "can't get window size"