What makes some version control systems better at merging?

Question

I\'ve heard that many of the distributed VCSs (git, mercurial, etc) are better at merging than traditional ones like Subversion. What does this mean? What sort of things do

Answer 1

Flippant answer: Why are some programming languages better at text/math than others?

Real answer: because they have to be. distributed VCSs do much of there merging at a point where the neither of the authors of the conflicting code can tweak the merge manually because the merge is being done by a third party. As a result, the merge tool has to get it right most of the time.

In contract with SVN you are doing something funky (and wrong?) if you ever end up merging something where you didn't write one side or the other.

IIRC most VCSs can shell out the merge to whatever you ask them to use, so there is (theoretically) nothing preventing SVN from using the GIT/mercurial merge engines. YMMV