DirState.update_basis_by_delta checks Tree[0]

[John Arbash Meinel]

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On 5/19/2011 2:21 AM, Robert Collins wrote:
> On Thu, May 12, 2011 at 1:48 AM, John Arbash Meinel
> <john at arbash-meinel.com> wrote:
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>> I'm trying to understand some failures that I've gotten when trying to
>> change pull and update to use "WT.update_basis_by_delta".
> 
> IIRC update_basis_by_delta is -specifically- written for commit, and
> has sanity checks (because it was risky). You may wish to remove them
> (stripping some overhead).
> 
> -Rob

Yeah, I've been rewriting it now. I ran into a lot of edge cases it
didn't handle. For example

In the WorkingTree we have ('dir', 'file', 'file-id'), but in the basis
tree we have ('other-dir', 'file', 'file-id'), and then the delta says
('other-dir/file', 'third-dir/file', 'file-id', ...)

The other one is if the tree has ('dir', 'file', 'file-id') and you add
('other-dir', 'file', 'file-id') you have to be able to sync the two,
even though they are at different paths.

It is a bit tricky to get right, but since I've seen the perf results, I
feel obligated to finish this off. :)

John
=:->

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