rcs co stops processing files after an empty revision file is encountered

# ----------------------- rcs co bug ------------------------
#
# when the rcs "co" command is given a file list which contains an
# rcs file that has no revison, e.g., rcs -i file, it fails
# with the following "Bad file number" error after failing to process the
# empty rev file and does not check out any remaining files in the list.
#
#       no revisions present; generating empty revision 0.0
#       co: output error: Bad file number
#       co aborted
#
#  This only happens if the empty rev file is *not* first in the list,
#
# In this test, only the first two runs will succeed
# because only those tests have the file with the empty revision first 
in the list

for test in "1 2 3"   "1 3 2"   "2 1 3"   "2 3 1"   "3 1 2"   "3 2 1"
do
        echo "--------------- test: $test ---------------"
        echo "remove all test files"
        rm -f co_bug.*
        echo "use rcs -i to create co_bug.1,v file"
        rcs -i -t-test co_bug.1
        echo "use ci to create empty co_bug.2,v and co_bug.3,v files"
        touch co_bug.2 co_bug.3
        ci -t-test co_bug.2 co_bug.3
        rcsfiles=""
        files=""
        for ext in $test
        do
                rcsfiles="$rcsfiles co_bug.$ext,v"
                files="$files co_bug.$ext"
        done
        echo "use co -f $rcsfiles to check out all files"
        co -f  $rcsfiles
        exit_status=$?
        echo "co -f exit status : \$? = $exit_status"
        echo "use ls -l to list all checked out files"
        ls -l $files
done >$0.out 2>&1