Re: Reference for quote "creating branch is not the issue, merging is", in context of Subversion/Git

["Jakub Narębski" <jnareb@gmail.com>]

W dniu 26.02.2017 o 16:19, Igor Djordjevic pisze:
> Hello Michael,
> 
> On 26/02/2017 12:40, Michael Hüttermann wrote:
>> Linus Torvalds made a statement regarding merging/branching and stated
>> (as far as I know) that "creating branch is not the issue, merge is", in
>> context of Subversion/Git.
>> I do not find the origin source for that. Can you please help and point
>> me to a statement or article where Linus elaborated on this?
> 
> Could it be that you think of "Tech Talk: Linus Torvalds on Git"[1]
> (held on May 3, 2007)?
> 
> To give you some clue, here`s an excerpt from Linus' talk/presentation
> (taken from the transcript[2] containing the whole thing):
> 
>   "... Subversion for example, talks very loudly about how they do CVS
>   right by making branching really cheap. It's probably on their main
>   webpage where they probably say branching in subversion is O(1)
>   operation, you can do as many cheap branches as you want. Nevermind
>   that O(1) is actually with pretty large O I think, but even if it
>   takes a millionth of a second to do branching, who cares? It's the
>   wrong thing you are measuring. Nobody is interested in branching,
>   branches are completely useless unless you merge them, and CVS cannot
>   merge anything at all. You can merge things once, but because CVS
>   then forgets what you did, you can never ever merge anything again
>   without getting horrible horrible conflicts. Merging in subversion is
>   a complete disaster. The subversion people kind of acknowledge this
>   and they have a plan, and their plan sucks too. It is incredible how
>   stupid these people are. They've been looking at the wrong problem
>   all the time. Branching is not the issue, merging is..."
> 
> This specific branch/merge performance talk starts at 50:20[3], where
> the part quoted above comes at 51:34[4].

Note also that while "creating branch is not the issue, merge is"
remains true, modern Subversion (post 1.5) makes merging easy thanks
to svn:mergeinfo property.

Though it does it in completely different way than Git and other
"graph of commits" VCS-es, because of the "branch is directory"
philosophy, namely that it keeps information about what was merged
in, rather than finding common ancestor(s) and using this information
for resolving merge.

> 
> Please note that there`s more context before and after this excerpt
> that puts it all into the meant perspective, so you may really want
> to watch/listen/read the whole thing anyway.
> 
> Regards,
> Buga
> 
> [1] https://www.youtube.com/watch?v=4XpnKHJAok8
> [2] https://git.wiki.kernel.org/index.php/LinusTalk200705Transcript
> [3] https://youtu.be/4XpnKHJAok8?t=3020
> [4] https://youtu.be/4XpnKHJAok8?t=3094
>