`test -x` returns wrong results for directories

["Ethan Gardener" <eekee57@fastmail.fm>]

in rc-httpd, i rely on `test -x` to check if a directory is searchable. this works in plan9port, 9base, inferno (with root from host fs), gnu coreutils, and freebsd. it doesn't work in 9front, nor in labs plan 9. (the labs version tested was a live-cd from 2010.)

term% test -x static ; echo $status
test 13436: false
term% ls -ld static
d-rwxrwxr-x M 24 ethan adm 0 Mar 15 14:58 static
term% man 1 test | grep -- -x
          -x file    True if the file exists and has execute permis-
term% 

the word 'wrong' in the subject may be a little strong, but there doesn't seem to be an alternative test for searchable directories other than mucking about with ls -l | sed or awk. test(1) has nothing to say on the matter.

for anyone using rc-httpd, the intended logic in rc-httpd/handlers/dir-index is this:
	if(! test -r $full_path -a -x $full_path) {
a suitable workaround is to remove ` -a -x $full_path`.
9front's version of rc-http has a workaround which may break when test is fixed.
/rc/bin/rc-httpd/handlers/dir-index:/-x
	if(! test -r $full_path -x $full_path){
in plan 9 and gnu coreutils, this effectively replaces the logical and (-a) with a logical or. freebsd reports an error, 'unexpected operator'.