Re: [PATCH] Avoid bug in Solaris xpg4/sed as used in submodule

[Andreas Schwab <schwab@linux-m68k.org>]

Ben Walton <bwalton@artsci.utoronto.ca> writes:

> Excerpts from Andreas Schwab's message of Mon Apr 09 02:40:03 -0400 2012:
>
>> How about using 's|[^/][^/]*|..|g' instead, which should avoid the bug
>> as well.
>
> I'd be ok with that change if the changed semantics of the regex are
> ok in this application.  It's essentially the same as s|[^/]+|..|g,
> which requires at least one character.
>
> In the current code, if you do:
>
> echo '/' | sed -e 's|[^]*|..|g'
>
> you get: ../.. (from a working implementation).
>
> Your regex would see the result  be: /
>
> I don't think we'd ever be passing a plain /, but we might pass a
> fully qualified path /path/to/foo, which would see the result change
> from ../../../.. to /../../.. and that could have unintended impact.

AFAICS the variables at this point never contain a value with a leading
slash.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."