Re: Expanding Includes in .gitignore

From: Aaron Pelly <aaron@pelly.co>
Date: Oct 27, 2016, 20:28 UTC
Message-ID: <b20b458c-440d-df09-d2c7-e510ac20492c@pelly.co>
In-Reply-To: <20161027105026.e752znq5jv5a6xea@sigill.intra.peff.net>

On 27/10/16 23:50, Jeff King wrote:

> I'd shy away from an actual include directive, as it raises a lot of
> complications:

I'm leaning that way now too.

Show 6 quoted lines

>   - we parse possibly-hostile .gitignore files from cloned repositories.
>     What happens when I include ask to include /etc/passwd? Probably
>     nothing, but there are setups where it might matter (e.g., something
>     like Travis that auto-builds untrusted repositories, and you could
>     potentially leak the contents of files via error messages). It's
>     nice to avoid the issue entirely.

I understand the issue.

It's not obvious to me how using a .d solves this problem though.

>   - finding a backwards-compatible syntax

using .d directories solves this nicely in my opinion

> Whereas letting any of the user- or repo-level exclude files be a
> directory, and simply reading all of the files inside, seems simple and
> obvious.

Apart from backwards compatibility, unless there's something I'm missing.

> If you go that route, it probably makes sense to teach
> gitattributes the same trick.

Understood. I'll keep that in mind.

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>> In the case of a directory the plan would be to add links to files
>> stored/sourced elsewhere. This does pose a precedence question which I
>> haven't thought about yet, but probably makes it too hard for the
>> limited value it brings.
> 
> I think the normal behavior in such "foo.d" directory is to just sort
> the contents lexically and read them in order, as if they were all
> concatenated together, and with no recursion. I.e., behave "as if" the
> user had run "cat $dir/*".
> 
> That lets you handle precedence via the filenames (or symlink names).

That was my thinking at first, but I didn't want to bias the discussion.

> It
> can't handle all cases (some items in "00foo" want precedence over "01bar"
> and vice versa), but I don't think there's an easy solution. That's a
> good sign that one or more of the files should be broken up.

I've been burned by this myself by packages interfering with each other in /etc/sysctl.d

Could we put this down to caveat emptor? I think this sorting should be intuitive to most people these days, and simple to document and comprehend.