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by AceJohnny2 708 days ago
Tangentially, I like to work with Gerrit [1], which approaches the core problem in a different way...

"Stacked branches" seem to be a terminology which derives from Github/etc's approach to Pull Requests, where one PR maps to one atomic change. The PR can either be integrated in the repo as a merge, in which case you maintain the history of the PR and all its changes through its reviews, or as a squash-merge, in which case you flatten the PR's review history into one commit.

But what if you want to maintain a series of separate but related commits? PRs don't really help you there, so people ended up inventing the concept of Stacked Branches, as discussed in the article.

Gerrit took a different approach, and requires you to add metadata to each commit's message, the Change-Id. This way Gerrit can track your commit through its review evolution (since its SHA will change with each iteration). This also allows Gerrit to trivially track a series of related changes through their overall evolution, since it can use git's normal branch data to track commit's relation to each other, and the Change-Id to track one commit as it evolves.

In any case, both solutions demonstrate that Git lacks a way to track the evolution of specific commits throughout their review history (a 2D branch in a way), so review tools like Github/etc and Gerrit had to create their own solution on top of it.

[1] https://www.gerritcodereview.com/

2 comments

Yep, Git's semantics are seriously lacking (see also renames). In Reviewable, we work around this with heuristics: we use Change-Id if it happens to be available, and otherwise do best-effort loose lexical matching on the commit messages to match up pairs across a rebase. It works reasonably well in practice but it's a bunch of complex code that I'd rather not have to maintain...
i like gerrit as well. There is a sizable population of developers working on google's projects android/chrome etc. that is well versed with gerrit. I am surprised there is no company that provides gerrit service for people who don't want to move to github. Other git hosting services also try to emulate github with similar workflows. I would love to host projects on gerrit but i don't want to manage it by myself.
> I am surprised there is no company that provides gerrit service for people who don't want to move to github.

There's GerritForge: https://www.gerritforge.com/

We work with them. Good folks. They helped migrate Eclipse's home-managed Gerrit to their own space [1] on Gerrithub [2]

[1] https://git.eclipse.org/r/

[2] https://gerrithub.io/q/