Re: [PATCH] git-svn: Don't rely on $_ after making a function call

From: Junio C Hamano <junkio@cox.net>
Date: Apr 25, 2007, 21:13 UTC
Message-ID: <7v4pn4w41k.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <20070425205948.GA12375@untitled>

Eric Wong <normalperson@yhbt.net> writes:

Show 7 quoted lines

> Adam Roben <aroben@apple.com> wrote:
>> Many functions and operators in perl set $_, so its value cannot be relied upon
>> after calling arbitrary functions. The solution is simply to copy the value of
>> $_ into a local variable that will not get overwritten.
>
> Does this fix any particular bug?  It looks right to me
> and makes the code easier to follow, so;

I suspect Merlyn has better explanation, but...

     for (list) {
	...	
     }

loop implicitly localizes $_ and does not share this problem, which I really appreciate whenever I am writing Perl code, but often enough I was bitten by scripts that use "while (<$fh>)", which does not localizes $_, and made hard to spot bugs by clobbering $_.

I find the patch a good safety measure for any future breakages.