Re: [PATCH] t/Makefile: make sure that file names are truly platform-independent

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Peff & Junio,

On Mon, 15 Aug 2016, Jeff King wrote:

> On Mon, Aug 15, 2016 at 09:57:52AM -0700, Junio C Hamano wrote:
> 
> > I wonder if we already have a good mechanism to allow a project and
> > its participants (say, "me") to declare "in this project, pathnames
> > must conform to this rule" and help them avoid creating a tree that
> > violates the rule customized to their project.
> > 
> > I guess "write_index_as_tree()" would be one of the central places to
> > hook into and that covers an individual contributor or a patch applier
> > who ends up adding offending paths to the project, as well as a merge
> > made in response to a pull request (unless it is a fast-forward)
> > [*1*].  The pre-receive hook can also be used to inspect and reject an
> > attempt to push an offending tree into the history.

FWIW I think it should be at a different level. See below for more
details.

> > Such a mechanism would allow a project that wants participation by
> > folks with case insensitive filesystems to ensure that they do not
> > create a directory that has both xt_TCPMSS.h and xt_tcpmss.h at the
> > same time, for example, but the mechanism needs to allow visibility
> > into more than just a single path when the custom check is made (e.g.
> > a hook run in "write_index_as_tree()" can see all entries in the index
> > to make the decision; if we were to also hook into "add_to_index()",
> > the hook must be able to see other entries in the index to which the
> > new entry is being added).
> 
> I am not convinced this mechanism needs to be built into git. Because it
> happens to be about filenames, git at least has a hope of making sense
> of the various project rules.

Both of you gentle people may recall a conversation in December 2014 when
we scrambled to plug a hole where maliciously-chosen file names would have
allowed to wreak havoc with a local Git repository's config (among other
things).

We did plug it, but not before I proposed to exclude many more file names
than just maliciously-chosen ones. For example, I wanted to exclude all
file names that are illegal on Windows when core.protectNTFS was set to
true.

If we were to implement this "let's help cross-platform projects"
functionality, it would be at that same level.

However, I have to agree with Junio that Git is *not* targeting *all*
platforms. Conversely, any solution we implement to try to be helpful by
pointing out unportable file names will certainly fall short of *some*
project's requirement.

Given that we have no shortage of problems to solve, I would vote for
addressing portability only as far as Git and its intended target
platforms are concerned.

Ciao,
Dscho