[Bug 235] New: ash: incorrect word splitting with read builtin

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=235

           Summary: ash: incorrect word splitting with read builtin
           Product: Busybox
           Version: 1.13.x
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: enhancement
          Priority: P5
         Component: Standard Compliance
        AssignedTo: unassigned at busybox.net
        ReportedBy: truedfx at gentoo.org
                CC: busybox-cvs at busybox.net
   Estimated Hours: 0.0


The read builtin in ash performs word splitting differently depending on
whether the first character in $IFS is a space.

printf 'a\t\tb\tc\n' | busybox ash -c 'IFS=$(printf "\t") read a b c; echo
".$a. .$b. .$c."'
.a. .. .b       c.
printf 'a\t\tb\tc\n' | busybox ash -c 'IFS=$(printf " \t") read a b c; echo
".$a. .$b. .$c."'
.a. .b. .c.
printf 'a,,b,c\n' | busybox ash -c 'IFS="," read a b c; echo ".$a. .$b. .$c."'
.a. .. .b,c.
printf 'a,,b,c\n' | busybox ash -c 'IFS=" ," read a b c; echo ".$a. .$b. .$c."'
.a. .b. .c.

This isn't right. Whether multiple characters form a single field separator
depends on whether those characters themselves are whitespace characters, not
on whether space is present in $IFS. Current behaviour is different from how
IFS is handled during ordinary word splitting, different from what susv3
specifies, and different from other shells, so I'm going to assume this is
unintentional.

For reference, here's bash's behaviour:

printf 'a\t\tb\tc\n' | bash -c 'IFS=$(printf "\t") read a b c; echo ".$a. .$b.
.$c."'
.a. .b. .c.
printf 'a\t\tb\tc\n' | bash -c 'IFS=$(printf " \t") read a b c; echo ".$a. .$b.
.$c."'
.a. .b. .c.
printf 'a,,b,c\n' | bash -c 'IFS="," read a b c; echo ".$a. .$b. .$c."'
.a. .. .b,c.
printf 'a,,b,c\n' | bash -c 'IFS=" ," read a b c; echo ".$a. .$b. .$c."'
.a. .. .b,c.


-- 
Configure bugmail: https://bugs.busybox.net/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.