[MERGE][#56299] New option -C/--change for diff and status to show changes in one revision.

[Ian Clatworthy]

Lukáš Lalinský wrote:

> Another patch will follow that makes -r branch:..\bzr.dev work, because
> I wouldn't expect to have to use / in local paths on Windows.

bb: approve

> @@ -180,6 +180,10 @@
>              versioned=False):
>          from bzrlib.status import show_tree_status
>  
> +        if revision and len(revision) > 2:
> +            raise errors.BzrCommandError('bzr status --revision takes exactly'
> +                                         ' one or two revision specifiers')
> +
>          tree, file_list = tree_files(file_list)
>              
>          show_tree_status(tree, show_ids=show_ids,

A question: You've changed the status command to throw an exception if
more than 2 revisionspecs are passed. Why only that one? It seems we
could do that more centrally perhaps?

If so, could you move that code as part of the follow-up patch?

Otherwise, all good.

Ian C.