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Re: officially freezing svn:mergeinfo syntax

From: Paul Burba <ptburba_at_gmail.com>
Date: Mon, 23 May 2011 10:01:17 -0400

On Mon, May 23, 2011 at 9:45 AM, Paul Burba <ptburba_at_gmail.com> wrote:
> On Mon, May 23, 2011 at 8:29 AM, Greg Stein <gstein_at_gmail.com> wrote:
>> I've been assuming the syntax is frozen for a long time now, so yeah...
>> freeze it more :-)
>> On May 23, 2011 8:12 AM, "Stefan Sperling" <stsp_at_elego.de> wrote:
>>> The recent fix for issue #3895 ("repos layer does not verify mergeinfo
>>> syntax") implies that the syntax of svn:mergeinfo is frozen and cannot
>>> be changed in future release without breaking compatibility of newer
>>> clients with 1.7 servers.
>>>
>>> We also backported this change to 1.6.17.
>>>
>>> I am pointing this out on dev@ since it might not be obvious to those
>>> who haven't reviewed the change.
>>>
>>> Do people think that this might cause problems?
>>>
>>> I would say it is not a problem because current clients will already
>>> error out hard if the syntax is changed (see also issue #3896) so we're
>>> effectively already stuck with the current syntax.
>
> Agreed, either *potentially* break future clients with 1.6.17-1.7.x
> repositories or *definitely* break existing clients exposed to invalid
> mergeinfo that got into <1.6.16 repositories.  We need to pick our
> poison at this point and protecting existing clients against a
> demonstrated problem strikes me as a better choice than worrying about
> potential mergeinfo syntax changes.
>
> FWIW I read issue #3896 to describe the problems with a client when
> *invalid* mergeinfo enters the repository; though the same problems
> hold for older clients if we purposefully change the syntax.

I'm taking a look at issue #3896 today. It's something we should do
sooner rather than later. If users encounter issue #3895 we want a
better answer (i.e. upgrade to 1.7 client) than what we can provide
right now: "Dump/edit/load your repository, with a lot of hand-waving
on the edit part".

Paul

>>> We can always add a new property (e.g. svn:mergeinfo2) if we want
>>> to add information or use a new syntax.
>>>
>>> Thoughts?
>
> In an ideal world we would have laid the groundwork in 1.5 clients for
> this, with separate mergeinfo syntax checking for repository-provided
> mergeinfo vs. client/user provided/generated mergeinfo (disable merge
> tracking given the former, error out given the latter).  Or ever
> better, the repository could have provided the syntax it supports.
> Regardless, we didn't foresee the need and so we are stuck with what
> we have.
>
> Paul
>
Received on 2011-05-23 16:01:46 CEST

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