With git and github you can have the best of both worlds. merge commits (seperate tree), linearized at the end (--no-ff) or rebased commits (pull --rebase).
1 and 3 have their usecases, 3 is esp. useful if the branch contains only 1-2 commits, and 1 is useful if the branch contains > 10. You can add test information into the merge commit.
I hope github will take more gerrit features into their tracker or allow tracker extensions, so that we can live with github alone. gerrit still is a UI and performance nightmare.
The merge history is the true one, it's what you want when browsing backwards to see how particular things changed. Rebase creates fake commits corresponding to a tree that never actually existed anywhere. Your history viewer should be able to linearize the tree for you if you want, but the canonical history in the repository should be the true one.
For Go, we will require that contributors (everyone working on Go) prepare their commit at head (or at least make the commit able to be automatically rebased). It makes no sense to have a merge commit for every single commit. That would add no extra information and double the size of the commit log.
It's not a merge commit for every single commit, only for every, well, merge. I sure hope people are writing new features or bugfixes in several commits, not just doing days of work and committing at the end (though I guess that would be a workflow for people who are worried about the size of the commit log).
What's the purpose of keeping a commit history at all? Really, what are your use cases? For me, the history is for looking around and understanding a particular change, or for bisecting to help understand a bug. Both of these use cases are better supported by seeing the tree as it actually was when someone was working on it, than by seeing an artificial, rebased history. What's your use case where the rebased version makes sense?
1 and 3 have their usecases, 3 is esp. useful if the branch contains only 1-2 commits, and 1 is useful if the branch contains > 10. You can add test information into the merge commit.
I hope github will take more gerrit features into their tracker or allow tracker extensions, so that we can live with github alone. gerrit still is a UI and performance nightmare.