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bug#6388: Should not match data be set on misses?
From: |
Eli Zaretskii |
Subject: |
bug#6388: Should not match data be set on misses? |
Date: |
Wed, 09 Jun 2010 22:03:08 -0400 |
> From: Lennart Borgman <lennart.borgman@gmail.com>
> Date: Thu, 10 Jun 2010 02:42:59 +0200
> Cc:
>
> (let ((ret (re-search-forward "some weird thing" (point-at-eol) t)))
> (message "ret=%s, mb0=%s, 1" ret (match-beginning 0) (match-beginning 1)))
>
> gives me messages like
>
> ret=nil, mb0=517, 1
>
> I expected
>
> ret=nil, mb0=nil, nil
I'm closing this bug report because the ELisp manual explicitly
documents the current behavior:
Every successful search sets the match data. Therefore, you should
query the match data immediately after searching, before calling any
other function that might perform another search. Alternatively, you
may save and restore the match data (*note Saving Match Data::) around
the call to functions that could perform another search.
A search which fails may or may not alter the match data. In the
past, a failing search did not do this, but we may change it in the
future. So don't try to rely on the value of the match data after a
failing search.
Patches welcome to "change this in the future" (unless Stefan or
Yidong object to such a change).