Re: [patch] vc-find-root with invert

[David Kastrup <dak@gnu.org>]

Justin Bogner <mail@justinbogner.com> writes:

> Stefan Monnier wrote:
>>>> Reading the docstring, my guess would be: vc-find-root walks the dir
>>>> tree up _until_ it finds WITNESS (as an evidence for the VC tree's root
>>>> dir). Unless we have CVS or SVN or similar, where every subdir has
>>>> WITNESS, so the root would be the last up-tree directory having WITNESS.
>>
>> That still doesn't tell me what it does.  I mean I can read the code and
>> understand what is the effect of calling the code like this, but I have
>> no idea what effect it has for the user.  AFAICT it's a misfeature.
>>
>>> This is exactly correct, though in the current trunk there is a bug
>>> such that the function does not behave like this. The patch causes it
>>> to work as documented.
>>
>> I think we should remove this misfeature rather than fix it.
>
> There are two types of version control directory, ones with a "root"
> directory in each directory under version control, and on with a
> "root" directory in the root of the version control. Since this
> function's purpose is to find the actual root of the tree, the latter
> case is simple, where it needs only find the "root" directory.
>
> However, for the other case, we need traverse upwards until we don't
> find the directory, returning the last one that does.

Why?  CVS or SVN do not do this either.  Subdirectories with .svn in
them are self-contained work directories with associated repository
location.

> As far as getting rid of invert, we could do that, and the function
> would then return something more reasonable than it does now, but it
> wouldn't actually find the root unless you happened to try the root
> first.

There is no dedicated root in CVS or SVN.  You never need to look at
.. in order to do local operations.  You can move your directory out to
a different location under a different "root" and things will work just
the same from there.

Which is pretty much the principal reason for every directory having its
own CVS or .svn subdirectories.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum