1.9rc1 countdown

[John Arbash Meinel]

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Martin Pool wrote:
> On Thu, Oct 30, 2008 at 8:41 PM, Martin Pool <mbp at canonical.com> wrote:
>> On Thu, Oct 30, 2008 at 7:44 PM, Martin Albisetti <argentina at gmail.com> wrote:
>>> On Thu, Oct 30, 2008 at 8:37 AM, Martin Pool <mbp at canonical.com> wrote:
>>>> * 1.9 format (uses btree indexes) -- and make this the default?
>>> I know this has been discussed somewhere, but I can't find it.
>>> Is this format rich-root?
>> It still has rich-root as a separate format, but this issue was
>> mentioned in that thread.  I'd like to just make it rich-root and ask
>> people to upgrade, but I'd like to understand if there would be any
>> deleterious effects in doing so.
> 
> One effect is that upgrading to rich-root is relatively slower than
> just updating the indexes or other similar transitions, since we need
> to update all inventories.
> 
> I spoke to Robert about this briefly on irc.
> 
>  * We should check that not only are inventories updated correctly
> when moving in to a rich-root form, but also their sha is updated in
> the revision object.
>  * People may have repositories in the wild that (incorrectly, maybe
> through using very old buggy versions?) mix rich-root and non content,
> and we should ensure check/reconcile will detect and fix this.  Robert
> has a patch for check but not for reconcile.
> 
> <lifeless> and yes, while the default isn't rich root, I think there
> are clear drawbacks to adding a new format that is a trapdoor for
> users on the default
> 
> I can't parse that.  If we made the default format rich-root, then it
> would be the default.
> 

So one of the problems with upgrading to rich-root is that when someone
commits in a rich-root repo, that patch cannot be applied to a
non-rich-root repository.

We've run into this in the past when people were experimenting, and
accidentally upgraded something to rich-root. They had to downgrade, and
do another commit before we could merge there changes.

I believe what Robert is saying is that "I think there are drawbacks to
making a trapdoor format the default."

For example, once rich-root is default doing:

bzr init-repo .
bzr branch http://upstream

Will convert to the new format, and they will no longer be able to merge
their changes back into "upstream" without upgrading it.

John
=:->
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