Re: [PATCH] no mergeinfo on 'mergeinfo NON-affecting' wc-to-wc copy

Mark Phippard wrote:
> On Wed, Sep 10, 2008 at 10:27 AM, C. Michael Pilato <cmpilato_at_collab.net> wrote:
>
>>> 2008/9/10 Danil Shopyrin <danil_at_visualsvn.com>:
>>>> Hi!
>>>>
>>>> Here is the patch that is trying to fix on of the problem discussed at
>>>> http://svn.haxx.se/dev/archive-2008-08/0793.shtml
>>>> [[
>>>> 2) Mergeinfo produced during WC-to-WC copy differs from equivalent
>>>> REPO-to-REPO copy. If you copy file in working copy and there is no
>>>> mergeinfo in the working copy then the new file will get an empty
>>>> mergeinfo record. Similar REPO-to-REPO copy operation doesn't produce
>>>> empty mergeinfo record.
>>>> ]]
>>>>
>>>> The general idea of the patch is as follows: we don't produce any
>>>> mergeinfo record if we [definitely] know that it's unnecessary. The
>>>> patch should ease the pain in the most cases. For example, it's not
>>>> needed to worry about mergeinfo in the cases when:
>>>> a. copy is performed within a working copy (it's just a 'local file
>>>> rename because of refactoring')
>>>> b. there is no merges except ones on the trunk/branches level (or
>>>> there is no merges at all)
>>>>
>>> The patch looks correct, but I think it's more complicated than it
>>> needs to be. I'd rather not put the extra checks in a different
>>> function, and I don't think you need to extend
>>> svn_client__get_wc_mergeinfo().
>>>
>>> In propagate_mergeinfo_within_wc(), we need to do the following:
>>>
>>> 1. Get the mergeinfo for the source. If it's explicit, not inherited,
>>> we're done, there's nothing to propagate, because the destination
>>> already has the same explicit mergeinfo as the source, as a result of
>>> the copy. Currently, propagate_mergeinfo_within_wc() calls
>>> calculate_target_mergeinfo(), we can replace this with a call to
>>> svn_client__get_wc_mergeinfo().
>>> 2. Figure out which path the destination inherits mergeinfo from, if any.
>> ...making sure to honor the wc-to-wc copy's promise not to talk to the
>> repository. If, in this scenario, you don't find any inheritable
>> mergeinfo in a working copy parent, you must not assume that *no*
>> parent has mergeinfo (since maybe you only checked out /trunk/project
>> but it's /trunk that carries the mergeinfo). Unless you can otherwise
>> determine that's safe not to do so in this case, you must continue to
>> set the empty mergeinfo property on the copy destination.
>
> Is it possible to do the logic at commit time and discard the property
> if it is not needed?

I trust you mean, "to *also* do the logic at commit time"? We already
discussed how delaying the logic altogether could mean corrupting merges
made into a copied-but-uncommitted directory. And I would suspect that
introducing the commit-time mergeinfo calculation has its own problems (at
the very least, WC schema changes to persist the previously calculated
value, complexity to ensure that we aren't blowing away a user's 'svn merge
--record-only' results, etc.)

It suspect it can be done. I suspect it comes with a great price of
complexity and special-cased-ness.

-- 
C. Michael Pilato <cmpilato_at_collab.net>
CollabNet   <>   www.collab.net   <>   Distributed Development On Demand