Re: [PATCH] check_refname_component: Optimize

From: Duy Nguyen <pclouds@gmail.com>
Date: May 31, 2014, 11:21 UTC
Message-ID: <CACsJy8BcmT1AKe=EYrYUs9Xyu9YUNbA3YUDafg2rZ9fabVgEiQ@mail.gmail.com>
In-Reply-To: <20140530000728.GC28683@sigill.intra.peff.net>

On Fri, May 30, 2014 at 7:07 AM, Jeff King <peff@peff.net> wrote:

> But then we're just trusting that the "trust me" flag on disk is
> correct. Why not just trust that packed-refs is correct in the first
> place?

I missed one thing in the first reply: because packed-refs is a plain text file, the user could be tempted to edit it manually (I know I did a few times for fast rename) and so it could not be trusted. If we ignore this (and I think we can, it's not like we encourage people to edit files in $GIT_DIR), then #3 and #4 are as good as #2.

Show 19 quoted lines

>
> IOW, consider this progression of changes:
>
>   1. Check refname format when we read packed-refs (the current
>      behavior).
>
>   2. Keep a separate file "packed-refs.stat" with stat information. If
>      the packed-refs file matches that stat information, do not bother
>      checking refname formats.
>
>   3. Put a flag in "packed-refs" that says "trust me, I'm valid". Check
>      the refnames when it is generated.
>
>   4. Realize that we already check the refnames when we write it out.
>      Don't bother writing "trust me, I'm valid"; readers can assume that
>      it is.
>
> What is the scenario that option (2) protects against that options (3)
> and (4) do not?

-- 
Duy