What makes merging in DVCS easy?

Question

I read at Joel on Software:

With distributed version control, the distributed part is actually not the most interesting part.

The inte

Answer 1

Part of the reason is of course the technical argument that DVCSes store more information than SVN does (DAG, copies), and also have a simpler internal model, which is why it is able to perform more accurate merges, as mentioned in the other responses.

However probably an even more important difference is that because you have a local repository, you can make frequent, small commits, and also frequently pull and merge incoming changes. This is caused more by the ‘human factor’, the differences in the way a human works with a centralised VCS versus a DVCS.

With SVN, if you update and there are conflicts, SVN will merge what it can and insert markers in your code where it can’t. Big big problem with this is that your code will now no longer be in a workable state until you resolve all the conflicts.

This distracts you from the work you are trying to achieve, so typically SVN users do not merge while they are working on a task. Combine this with the fact that SVN users also tend to let changes accumulate in a single large commit for the fear of breaking other people’s working copies, and there will be large periods of time between the branch and the merge.

With Mercurial, you can merge with incoming changes much more frequently inbetween your smaller incremental commits. This will by definition result in less merge conflicts, because you will be working on a more up-to-date codebase.

And if there turns out to be a conflict, you can decide to postpone the merge and do it at your own leisure. This in particular makes the merging so much less annoying.