Re: Proposal: sharing .git/config

[Jeff King <peff@peff.net>]

On Tue, Mar 12, 2013 at 01:01:08AM +0530, Ramkumar Ramachandra wrote:

> > But it was pointed out that you could also just do:
> >
> >   $ git config include.ref upstream-config
> >   $ git show origin/config ;# make sure it looks reasonable
> >   $ git show origin/config >.git/upstream-config
> >
> > and so forth. There are some ways that a pure ref can be more
> > convenient (e.g., if you are carrying local changes on top of the
> > upstream config and want to merge), but ultimately, you can replicate
> > any include.ref workflow with include.path by adding a "deploy" step
> > where you copy the file into $GIT_DIR.
> 
> This seems to be unnecessarily complex and inelegant.  Maybe this
> functionality is best managed as a separate git repository: `repo`
> from depot_tools uses a manifest repository containing all the project
> metadata.  Maybe we can extend it/ write an more general version?

I don't think you can avoid the 3-step problem and retain the safety in
the general case.  Forgetting implementation details for a minute, you
have either a 1-step system:

  1. Fetch and start using config from the remote.

which is subject to fetching and executing malicious config, or:

  1. Fetch config from remote.
  2. Inspect it.
  3. Integrate it into the current config.

We can automate the sequence to remove as much friction as possible, but
fundamentally step 2 requires some effort from the user.  Moving the
config to a separate repo does not get rid of those steps.  The user
either does not look at the config before using it, in which case we are
no better than the 1-step scenario, or they do, in which case they are
replicating the 3-step scenario.

The other alternative is to automate step 2. The simplest way would be
to have a whitelist of "ok to share" config, that would not include
things like diff.external that can run arbitrary code. I don't know
whether that would make the system too limited for what people want to
do. Do we have a concrete example of what config people would like to
share in this manner?

-Peff