Friday, May 24, 2013

Git 1.8.3 and even more leftover bits

The 1.8.3 release has finally been tagged and pushed out to the usual places. Also the release tarballs at are back.

For a list of highlights, please see the previous post on -rc2; not much has changed since then.

During the last development cycle including its pre-release feature freeze, a few more interesting topics were discussed, and at this moment there aren't actual patches or design work.

[Previous list of "leftover bits" is here]
  • "git config", when removing the last variable in a section, leaves an empty section header behind. Anybody who wants to improve this needs to consider ramifications of leaving or removing comments.
    Cf. $gmane/219524
  • [STARTED AND THEN STALLED] Add "git pull --merge" option to explicitly override configured pull.rebase=true. Make "git pull" that does not say how to integrate fail when the result does not fast-forward, and advise the user to say --merge/--rebase explicitly or configure pull.rebase=[true|false]. An unconfigured pull.rebase and pull.rebase that is explicitly set to false would mean different things (the former will trigger the "fast-forward or die" check, the latter does the "pull = fetch + merge".
    Cf. $gmane/225326
  • Teach more commands that operate on branch names about "-" shorthand for "the branch we were previously on", like we did for "git merge -" sometime after we introduced "git checkout -".
    Cf. $gmane/230828
  • Proofread our documentation set, and update to reduce newbie confusion around "remote", "remote-tracking branch", use of the verb "to track", and "upstream".
    Cf. $gmane/230786.

Monday, May 13, 2013

Git 1.8.3-rc2

The second and planned-to-be-the-final release candidate for the upcoming 1.8.3 release was tagged today. Also, the release tarballs at are back ;-)

Hopefully we can have the final late next week, but we might end up doing another release candidate. Please help testing the rc2 early to make sure you can have a solid release.

There are numerous little fixes, new features and enhancements that cannot be covered in a single article, so I'll only highlight some selected big-picture changes here. For the full list of changes, please refer to the draft Release Notes.

Preparation for 2.0

A lot of work went into preparing the users for 2.0 release that will come sometime next year, which promises large backward-incompatible UI changes:
  • "git push" that does not say what to push from the command line will not use the "matching" semantics in Git 2.0 (it will use "simple", which pushes your current branch to the branch of the same name only when you have forked from it previously; e.g. "git push origin" done while you are on your "topic" branch that was previously created with "git checkout -t -b topic origin/topic" will push your "topic" branch to origin).

    This default change will hurt old-timers who are used to the traditional "matching" (if you have branches A, B and C, and of the other side has branches A and C, then your branches A and C will update their branches A and C, respectively), and they can use "push.default" configuration variable to keep the traditional behaviour. I.e.

    $ git config push.default matching

    Recent releases since 1.8.0 has been issuing warnings when you do not have any push.default configuration set, and this release continues to do so.

  • "git add -u" and "git add -A" that is run inside a subdirectory without any other argument to specify what to add will operate on the entire working tree in Git 2.0, so that the behaviour will be more consistent with "git commit -a" (e.g. "edit file && cd subdir && git commit -a" will commit the change to the file you just edited which is outside the directory you ran "git commit" in).

    Users can say "git add -u ." and "git add -A ." (the "dot" means "the current directory") to limit the operation to the subdirectory the command is run in with the traditional versions of Git (and this will stay the same in Git 2.0 or later), so there will be no configuration variable to change the default.

    The 1.8.3 and later releases do not yet change the behaviour until Git 2.0, and limit these operations to the current subdirectory, but they do notice when you have changes outside your current subdirectory and warn, saying that if you were to type the same command to Git 2.0, you would be adding those other files to your index, and encourages you to learn to add that explicit "dot" if you mean to add changed or all files in the current subdirectory only.

  • "git add path" has traditionally been a no-op for removed files (e.g. "rm -f dir/file && git add dir" does not record the removal of dir/file to the index), but Git 2.0 will notice and record removals, too.

    The 1.8.3 and later releases do not yet change the behaviour until Git 2.0, but they do notice when you have removed files that match the path and warn, saying that if you were to type the same command to Git 2.0, you would be recording their removal, and encourages you to learn to use the --ignore-removal option if you mean to only add modified or new files to the index.

Tightening of command line verification

There are quite a many UI fixes that tie loose ends. Some commands assumed that the users were perfect and would never throw nonsense command line arguments at them, and some operations that need two parameters were happily carried out even when they got three parameters without diagnosing such a command line as an error (the excess one was simply ignored).

Many of them have been updated to detect and die on such errors.

Helping our friends at Emacs land

We expedited the update of the foreign SCM interface to bzr we have in the contrib/ area since 1.8.2, and included a version that is vastly modified from what we had before, with help from some Emacs folks. This code could be a bit rougher than the rest of Git that usually moves slowly and cautiously, but we decided that, given the circumstance, it is more important to push out some improved version early, in order to help our friends in Emacs land, who have been (reportedly) suffering from less than ideal response to the issues they are having with their SCM of choice.

A beginning of a better triangular workflow support

The recommended workflows to collaborate with others are either:
  • to have your own repository and push your work there while pulling from your upstream to keep up to date, or
  • to have a central repository where everybody pushes to and pulls from.
The latter was primarily to make those who are coming from centralized version control systems feel at ease, and the repository configuration mechanisms such as "remote.origin.url" variable were designed to help that workflow (there is one "origin" you pull from and push to). The former however is also important, and many people on Git hosting sites (e.g. GitHub) employ this workflow (you pull from one place and push to another place, but they are not the same).

A new configuration mechanism "remote.pushdefault" has been introduced to support such a triangular workflow. After you clone from somebody else's project, that upstream repository will still be your 'origin', but you can add the repository you regularly push to in order to publish your work (and presumably then you will throw a "pull request" at the upstream) as another remote, and set it to this configuration variable. E.g.
$ git clone git:// frotz
$ cd frotz
$ git remote add publish ssh://
$ git config remote.pushdefault publish
After this, you can say "git push" and the push does not attempt to push to your origin (i.e. git://  but to your publish remote (i.e. ssh:// because of the last configuration.