[PREVIEW] line-endings support

[Ian Clatworthy]

John Arbash Meinel wrote:

> The big problem I have with this is how to handle when a file matches
> multiple
> patterns. One clear example is absolute paths versus extensions (though
> generally you would say that the abspath would take precedence.)
> 
> I can certainly create multiple rules that would match a single path. In
> that
> case, do they stack? Does one "win"? What are the rules for that (comes
> first
> alphabetically, comes first on the search list, comes last on the search
> list,
> matches more of the filename, etc.)

In the case of gitattributes, the doc is pretty clear:

* lower patterns in the file take precedence
* .gitattributes files have lower priority the further up the tree
  they are.

Those rules look good to me.

> If we make the patterns *only* filename extensions *or* absolute paths,
> we can
> make some of the processing operations a lot faster. And you are a lot less
> likely to run into problems. But then what do you do about
> extension-less files
> (Makefile, configure, bzr, etc).

For consistency, I think we need to make the pattern language consistent
with .bzrignore (and see how that performs). In my current code, I think
the performance overhead ought to be next to non-existent if there are
no filters. Once we do have filters, I expect the overhead they
introduce to generally, but not always, swamp any increase we see in
pattern matching time to enable them.

Ian C.