return value ignored sometimes when returning from within a loop

[Edward Welbourne]

Configuration Information [Automatically generated, do not change]:
Machine: i386
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i386' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i386-pc-linux-gnu' 
-DCONF_VENDOR='pc' -DSHELL -DHAVE_CONFIG_H   -I.  
-I/home/doko/packages/bash/bash-2.05a 
-I/home/doko/packages/bash/bash-2.05a/include 
-I/home/doko/packages/bash/bash-2.05a/lib -g -O2
uname output: Linux whorl 2.2.19pre17 #1 Tue Mar 13 22:37:59 EST 2001 i686 
unknown
Machine Type: i386-pc-linux-gnu

Bash Version: 2.05a
Patch Level: 0
Release Status: release

Description:
        I was parsing cvs log's output and the function I wrote to do
        it went strangely wrong.  The following silly script mimics
        what was going on:

#!/bin/bash
function demo () {
    echo -e 'a\nb\nc\n' | while read nom
    do if [ -z "$nom" ]
      then break
      elif [ "$nom" != a ]
      then
          [ "$nom" = b ] || break
          return 0
      fi
      echo "d'uh"
    done
    return 1
}

if demo
then echo Yes
else echo No
fi

        yes, I'm sorry, it's a bit contorted.  However, if I run it, I
        see the "d'uh" message once and get the answer No - i.e. demo
        returned 1, which I'm quite sure is wrong.  Indeed, if I
        replace each use of break with return 1, and remove the last
        line of the function, I see one "d'uh" and get the answer Yes,
        which is the behaviour I expect.  Alternatively (reverting to
        use of break and a dangling return 1) if I replace the
        "echo | while read" line with "for nom in a b c", the script
        again says "d'uh" once and answers Yes.

        If this is not a bug, it is certainly very strange behaviour.
        I've not tried to reduce it to a smaller test-case, but this
        can probably be done !

Repeat-By:
        Save the above script to a file, run it.
        Remove the "return 1" line and place each "break" with "return 1".
        Save the result to a second file, run it.
        Starting from the original, replace the "echo | while read" line
        with "for nom in a b c", save to a third file, run it.
        Notice how the output varies.

Fix:
        As indicated, I have a work-around; but no fix, sadly.