Re: [PATCH 1/1] mingw: only test index entries for backslashes, not tree entries

From: Junio C Hamano <gitster@pobox.com>
Date: Dec 26, 2019, 22:01 UTC
Message-ID: <xmqqfth6kaqi.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20191226214245.GA186931@google.com>

Jonathan Nieder <jrnieder@gmail.com> writes:

> Is there anything we can or should do to prevent people checking in
> new examples of paths with backslash in them (on all platforms)?

I obviously won't dictate what should happen on Windows, but I think the overall principle for paths recorded in a tree object that can be problematic on some of the platforms ought to be:

 * fsck and transfer.fsckobjects should be taught to notice
   offending characteristics (e.g. has a backslash in it, is one of
   the "reserved names" on some platform like LPT1).

 * if paths with the offending characteristics are *so* obviously
   useless in real life and are possible only in a crafted path that
   is only useful to attack users, the check in fsck should default
   to "reject" to help the disease spread via hosting sites.

 * otherwise, the check should be to "warn" but not "reject", so
   that projects can keep using paths that may problematic on
   platforms that do not matter to them.

I think LPT1 and friends fall into the "warning is fine" category, and a path component that contains a backslash would fall into the "this is an attack, just reject" category.