Re: Google Summer of Code 2009: GIT

From: saurabh gupta <saurabhgupta1403@gmail.com>
Date: Mar 19, 2009, 19:17 UTC
Message-ID: <ab9fa62a0903191217t5d0e6d9cn4915a425ed8084ff@mail.gmail.com>
In-Reply-To: <alpine.DEB.1.00.0903190003100.10279@pacific.mpi-cbg.de>

Hi all,

Sorry for replying so late as I was busy in my college's mid-semester exams :-|

On Thu, Mar 19, 2009 at 4:46 AM, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:

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> Hi,
>
> On Fri, 13 Mar 2009, saurabh gupta wrote:
>
>> On Fri, Mar 13, 2009 at 1:29 AM,  <david@lang.hm> wrote:
>> > On Fri, 13 Mar 2009, saurabh gupta wrote:
>> >
>> >> Very well described, David. I agree with you and providing these
>> >> merge options to the user, merge drivers can do the work and mark the
>> >> conflicts according to the option. The work to do is to modify the
>> >> merge driver. I think in this way, even people who have only a
>> >> terminal can also gain from it. They can choose the apt option to see
>> >> the conflict markers in their way. So, the aim is to make merge
>> >> driver configurable and create the merged/conflicted file according
>> >> to the options.
>> >
>> > for the GSOC I suspect that the right thing to do is the define one or
>> > more merge drivers to create, and list what applications are going to
>> > be used for testing these merges.
>> >
>> > you and the mentor can decide what is a reasonable amount of work.
>>
>> I will very glad to hear about this thing from the mentor (Johannes
>> Schindelin, according to wiki). I will try to plan out the things in a
>> proper way to carry out this project if I get a chance to work on this
>> for GSoC 2009.
>
> Well, now that we have been accepted as an organization, we can move
> forward with this idea!

Congrats for getting accepted in GSoC 2009.

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> My main concern is that we define early on what should be the user
> interface, preferably with a quick sketch.
>
> The technical details, we can hash them out later, I have no doubt that
> with the help of the complete Git community, we can overcome almost every
> problem handling XML data or some such.
>
>> > it may be just doing an XML merge driver is a summer's worth of work,
>> > or it may be that it's not really enough and you should try to do
>> > another one or two.
>> >
>> > it also may be that there is a lot of overlap between different merge
>> > drivers, and once you have the XML driver the others become fairly
>> > trivial to do. (I'm thinking the config file examples I posted earlier
>> > in the thread)
>>
>> with the options given to the user, one can handle the config files
>> also where order doesn't matter and also the whitespaces problem can
>> also be handled in the similar way.
>
> In my humble opinion, we should focus on the data types we want to be
> able to support at the end of the summer first.
>
> For example, if we decide that OOXML is a must (as it is a proper
> standard, and many people will benefit from it), we will most likely end
> up in having to write a merge _driver_ (to handle those .zip files), _and_
> a merge _helper_, although we can avoid writing our own GUI, as we can
> create an OOXML that has its own version of conflict markers.

Well, for ODF type document, we can write a merge driver which will change the xml file in an appropriate way that OO can understand it and the user can see the merge result/conflict in a comfortable way. As described by Junio, in this case, a dedicated merge helper is not needed as OO can parse the markers made by merge-driver and provide the user to resolve the conflict and register the changes to index.

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>
> If we decide that SVG is something we want to support by the end of the
> summer, then we can probably avoid writing a merge _driver_, as plain text
> is handled reasonably well in Git.  OTOH it could turn out that there are
> _real_ conflicts in overlapping tag ids, and it would still be easier to
> write a merge driver, too.

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>
> IOW the details are not as important as
>
> - knowing what data types we want to support _at the least_, and what data
>  types we keep for the free skate,

As of now, how about going for XML files. For this summer, we can go for XML files and latex files can be handled later.

>
> - a clear picture of the user interface we want to be able to provide,

In my opinion, we have following things to do:

=> while merging an ODF document, merge-driver will merge the file at file level. If changes don't overlap, then it returns the result with a success. For example, if the file is changed only on one side, then the driver will simply add the new content.

=> If conflicts appear, then the merge driver will put the markers in an appropriate manner which the end-user application (e.g. open office) can understand and show the user. For example, the XML file of that ODF document will be modified and OO can show it to user in its way. We will have to study about the OO style of version marking. Another method is to implement the marker style in our own way. For example, to show any marker, the XML file is modified so that user can see markers like ">>>> " or "====" in openoffice....In this case, we will have to just change the xml content in this way.

>
> - a timeline (weekly milestones should be fine, I guess) what should be
>  achieved when, and

Timeline can be decided once we reach some conclusion and the work which needs to be done become clear to us.

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> - being flexible in how to support that (IOW if a merge driver appears
>  unnecessary first, but necessary later, we should be able to fit that
>  into both the design and the timeline).
>
> How does that sound?
>
> Ciao,
> Dscho
>
>

-- 
Saurabh Gupta
Senior,
NSIT,New Delhi, India