[Help-smalltalk] What is supposed to happen when upToAll: hits the end of stream?

[Rick Flower]

I've got some code looking for a line of "----------------" but at
the very end of the stream it may instead find a line of "=========".
In this case I see this error in version 3.2:

error: Invalid argument nil: must be a Character
SystemExceptions.WrongClass(Exception)>>signal (ExcHandling.st:254)
SystemExceptions.WrongClass class>>signalOn:mustBe: (SysExcept.st:805)
SystemExceptions.WrongClass class>>signalOn:mustBe: (SysExcept.st:801)
String(Object)>>checkIndexableBounds:put: (Object.st:825)
String>>at:put: (String.st:329)
WriteStream>>nextPut: (WriteStream.st:93)
FileStream(Stream)>>upToAll: (Stream.st:264)

The line I was executing was this:
(pipe upToAll: '----------------------------')

The content of the pipe when this was issued was this (sans the quotes) :

"Initial revision
============================================================================="
<end of pipe>

Any ideas on whether this was proper handling or not?  I was hoping
it would return the entire string which is what I think it should 
be doing based on reading the docs.. 
Comments?