Re: Editorr v2 svn_editor_alter_directory needs list of children

Philip Martin wrote:

> I think alter_directory needs a list of children as well as the new
> properties.

I agree.  I already felt that was needed for API symmetry (or else the add_directory() should *not* take the list of children).  Now your use case below adds a practical reason.

>  Consider an update from
>
>   relpath  revision props
>               3
>   A          3      p=v
>   A/X        3
>
> to
>
>   relpath  revision props
>               4
>   A          4      p=vvv
>   A/X        4
>   A/Y        4
>
> The v2 editor drive will call alter_directory to change the properties
> on A and add_directory to add the child A/Y.
>
> The alter_directory call cannot change the properties of A without
> changing the revision, but it cannot simply change the revision of A if
> A/Y has not yet been added.  The best solution seems to be that
> alter_directory should have a list of the children, just like
> add_directory, then it can add any missing children as incomplete,
> change the properties and update the revision.
>
> An alternative might be marking A incomplete, like a v1 drive.  I don't
> like that, I would prefer it if v2 could reserve incomplete for nodes
> that are just names and have no content.

An important point here is that, by knowing the list of children, the semantics of the WC "incomplete" status can be greatly simplified.  We will only ever need to make new children "incomplete", never the directory itself.  Now the "incomplete" status will only need to mean, "We know there is a node with this name; we know nothing else about it".  It will no longer ever need to mean "This directory has some children which are completely (or partially?) fleshed out, and/or perhaps some that we don't know anything about yet".

That simplification in itself sounds like a very good reason to go this way.

- Julian

> Another alternative might be imposing a drive order restriction, only
> allow alter_directory after all children have been added. I don't think
> that is right either, v2 tries to avoid depth order restrictions.
>
> If we consider a node's "content" to consist of text+props for
> files and
> children+props for directories then we see that the current alter_file
> already supplies all the content for file nodes while the current
> alter_directory only supplies part of the content for directory nodes.
> Adding children to alter_directory removes that difference.
>
> --
> uberSVN: Apache Subversion Made Easy
> http://www.uberSVN.com
>
Received on 2012-04-12 18:07:15 CEST