What VCS allows me to add changes to multiple pending commits simultaneously?

Question

My workflow usually involves me making multiple changes to a file, each of which belongs to it's own conceptual unit of change across the project (= commit).

What I would like to be able to do is to add certain diffs (either a whole file, or only certain lines of a file) to a pending commit (which would probably have to be named) and to have multiple pending commits 'active' at the same time.

Then when all changes related to a particular pending commit are complete across all files, I can commit the named commit!

Any ideas of which VCS would be a good candidate for this?

Answer 1

In svn, you can define changelists and then commit only the files in a particular changelist.

Git goes a bit further, and allows you to record patches by interactively selecting changed chunks from a file with git add -p.

Though popular, these features are contrary to best practices. You cannot test your changes properly in this way. Everything may work in your working copy, yet a commit of only part of the changes may break the build. Using feature branches is much safer, and any modern version control system supports this.

There are also the Mercurial ShelveExtension and git-stash, which allow you to shelve selected changes at the granularity of patch hunks for later commits. This way of working does allow you to test properly before committing.

Answer 2

The Subversion client (>=1.5) contains the notion of a changelist: a group of files which are associated with a chosen name.

This becomes especially useful when working on several different set of files within the same working copy. Instead of having to remember each file in each set, Subversion will allow you to associate a changelist with each set of files. Most commands which take a set of files as targets will now also accept the --changelist option, which filters those targets based upon the members of the changelist. Changelist membership can be edited using the new changelist subcommand.

Answer 3

It would be very hard to ensure that the commit of each separate change results in a buildable system.

I strongly recommend doing one thing at a time and commit each issue separately.

Answer 4

Content warning: my impression, based on only passing acquaintance:

If you need to micro-manage simultaneous but in some sense unrelated changes, then you may care to investigate darcs, which has a reversed emphasis when compared to systems like svn, git, or mercurial.

In darcs, the patch is the key element, and the state of a given branch is really just a summation of a set of patches. This model may suit what you are trying to do, but clearly @wcoenen's warning about best practice holds. For each set of patches, you'll need to ensure the build (whatever it might consist of) isn't broken.

BTW, are you the Eoghan M...r i think you are?

Answer 5

in bzr you can use shelve/unshelve commands to get some changes out of your files and then back, or use loom plugin to easily manage set of related patches. But neither of these will solve your original request, and I'm doubt any VCS can do it this way.

Answer 6

The original request sounds a lot like "cherry picking": manually selecting fragments of a "diff" to include in a new commit. At least Git and Darcs support that. For emacs + git there is gitsum, which I like a lot.