On 03/22/2012 07:59 AM, Martin Geisler wrote:
Thomas Heller<thom.heller@googlemail.com> writes:
On 03/21/2012 06:38 PM, Paul A. Bristow wrote:
Well both in working collaboratively on Boost.Math and a couple of GSoC projects, I have found that coming to commit and finding that someone else has committed a change is common.
Unless you agree who has temporary exclusive access to the code, it is all too easy to find that changes collide.
I'm unclear how git alters that (if at all) I have yet to understand. Same here ... But if we believe the git advocates, resolving those conflicts is easier with git. That's actually not true. DVCS tools are not magic and when there is a genuine conflict in SVN (the same region was editited in parallel by two developers) then you also get a conflict in Git and Mercurial.
The difference is that Git and Mercurial track the history more explicitly in their changeset graphs -- SVN has merge tracking after version 1.5, but according to the SVN authors, it's a fragile feature. I've heard from clients that they migrated to Mercurial after finding that Subversion had conflicts in the *meta data* that was supposed to track merges!
From what i understand it is partly due to the fact that gits merge algorithm is slightly better than svns. True, Mercurial and Git has a clearer picture of what's going on. I've already presented a case where Subversion fails to merge cleanly but Mercurial and Git will:
http://stackoverflow.com/a/2486662/110204
In the scenario, there is a rename on one branch and a modification on another branch.
This might also be due to the fact, that commits are broken into smaller pieces, thus the conflict is more isolated. No, the number of commits is not important for a three-way merge. This is a very common misunderstanding, though, and many blog posts keep saying this since it sounds intuitively correct.
But the fact is that a three-way merge is concerned with three things only: common ancestor, your version, and my version. The number of commits that went into producing your and my version is irrelevant.
I've written a little about it here:
http://stackoverflow.com/a/8592480/110204 http://stackoverflow.com/a/9500764/110204
Thanks for the clarifications!