Re: [PATCH 1/1] worktree refs: fix case sensitivity for 'head'

From: Jacob Keller <jacob.keller@gmail.com>
Date: Dec 14, 2018, 17:22 UTC
Message-ID: <CA+P7+xoxE0o=5fMQrDoyCgWMQ-By2t1LdApecRDWmoXXCfnFuw@mail.gmail.com>
In-Reply-To: <CACsJy8D9qfBLOUCyca+ws66uHx_tgoFZSTbTBxxW2fRQmyr_Nw@mail.gmail.com>

On Thu, Dec 13, 2018 at 11:38 PM Duy Nguyen <pclouds@gmail.com> wrote:

Show 8 quoted lines

> Even with a new ref storage, I'm pretty sure pseudo refs like HEAD,
> FETCH_HEAD... will forever be backed by filesystem. HEAD for example
> is part of the repository signature and must exist as a file. We could
> also lookup pseudo refs with readdir() instead of lstat(). On
> case-preserving-and-insensitive filesystems, we can reject "head" this
> way. But that comes with a high cost.
> --
> Duy

Once other refs are backed by something that doesn't depend on filesystem case sensitivity, you could enforce that we only accept call-caps HEAD as a psuedo ref, and always look up other spellings in the other refs backend, though, right? So, yea the actual file may not be case sensitive, but we would never create refs/head anymore for any reason, so there would be no ambiguity if reading the refs/head vs refs/HEAD on a case insensitive file system, since refs/head would no longer be a legitimate ref stored as a file if you used a different refs backend.

Basically, we'd be looking up HEAD by checking the file, but we'd stop looking up head, hEAd, etc in the files, and instead use whatever other refs backend for non-pseudo refs. Thus, it wouldn't matter, since we'd never actually lookup the other spellings of HEAD as a file. Wouldn't that solve the ambiguity, at least once a repository has fully switched to some alternative refs backend for non-pseudo refs? (Unless I mis-understand and refs/head could be an added pseudo ref?)

Jake