Archive for the 'cinnabar' Category

Git-cinnabar is a git remote helper to interact with mercurial repositories. It allows to clone, pull and push from/to mercurial remote repositories, using git.

Get it on github.

These release notes are also available on the git-cinnabar wiki.

What's new since 0.3.2?

• Various bug fixes.
• Updated git to 2.9 for cinnabar-helper.
• Now supports bundle2 for both fetch/clone and push (https://www.mercurial-scm.org/wiki/BundleFormat2).
• Now Supports git credential for HTTP authentication.
• Removed upgrade path from repositories used with version < 0.3.0.
• Experimental (and partial) support for using git-cinnabar without having mercurial installed.
• Use a mercurial subprocess to access local mercurial repositories.
• Cinnabar-helper now handles fast-import, with workarounds for performance issues on macOS.

If you've been following this blog, you know I've been working on a git remote helper that gives access to mercurial repositories, named git-cinnabar. So far, it has been using libraries from mercurial itself in order to talk to local or remote repositories.

That is, until today. The current master branch now has experimental support for direct access to remote mercurial repositories, without mercurial.

Git-cinnabar is a git remote helper to interact with mercurial repositories. It allows to clone, pull and push from/to mercurial remote repositories, using git.

Get it on github.

These release notes are also available on the git-cinnabar wiki.

This is mostly a bug and regression-fixing release.

What's new since 0.3.1?

• Fixed a performance regression when cloning big repositories on OSX.
• git configuration items with line breaks are now supported.
• Fixed a number of issues with corner cases in mercurial data (such as, but not limited to nodes with no first parent, malformed .hgtags, etc.)
• Fixed a stack overflow, a buffer overflow and a use-after free in cinnabar-helper.
• Better work with git worktrees, or when called from subdirectories.
• Updated git to 2.7.4 for cinnabar-helper.
• Properly remove all refs meant to be removed when using git version lower than 2.1.

This is a brown paper bag release. It turns out I managed to break the upgrade
path only 10 commits before the release.

What's new since 0.3.0?

• git cinnabar fsck doesn't fail to upgrade metadata.
• The remote.$remote.cinnabar-draft config works again.
• Don't fail to clone an empty repository.
• Allow to specify mercurial configuration items in a .git/hgrc file.

Git-cinnabar is a git remote helper to interact with mercurial repositories. It allows to clone, pull and push from/to mercurial remote repositories, using git.

Get it on github.

These release notes are also available on the git-cinnabar wiki.

Development had been stalled for a few months, with many improvements in the next branch without any new release. I used some time during the new year break and after in order to straighten things up in order to create a new release, delaying many of the originally planned changes to a future 0.4.0 release.

What's new since 0.2.2?

• Speed and memory usage were improved when doing git push.
• Now works on Windows, at least to some extent. See details.
• Support for pre-0.1.0 git-cinnabar repositories was removed. You must first
  use a git-cinnabar version between 0.1.0 and 0.2.2 to upgrade its metadata.
• It is now possible to attach/graft git-cinnabar metadata to existing commits
  matching mercurial changesets. This allows to migrate from some other
  hg-to-git tool to git-cinnabar while preserving the existing git commits.
  See an example of how this works with the git clone of the Gecko mercurial
  repository
• Avoid mercurial printing its progress bar, messing up with git-cinnabar's
  output.
• It is now possible to fetch from an incremental mercurial bundle (without
  a root changeset).
• It is now possible to push to a new mercurial repository without -f.
• By default, reject pushing a new root to a mercurial repository.
• Make the connection to a mercurial repository through ssh respect the
  GIT_SSH and GIT_SSH_COMMAND environment variables.
• git cinnabar now has a proper argument parser for all its subcommands.
• A new git cinnabar python command allows to run python scripts or open a python shell with the right sys.path to import the cinnabar module.
• All git-cinnabar metadata is now kept under a single ref (although for
  convenience, other refs are created, but they can be derived if necessary).
• Consequently, a new git cinnabar rollback command allows to roll back to
  previous metadata states.
• git-cinnabar metadata now tracks the manifests DAG.
• A new git cinnabar bundle command allows to create mercurial bundles,
  mostly for debugging purposes, without requiring to hit a mercurial server.
• Updated git to 2.7.0 for the native helper.

Development process changes

Up to before this release closing in, the master branch was dedicated to
releases, and development was happening on the next branch, until a new
release happens.

From now on, the release branch will take dot-release fixes and new
releases, while the master branch will receive all changes that are
validated through testing (currently semi-automatically tested with
out-of-tree tests based on four real-life mercurial repositories, with
some automated CI based on in-tree tests used in the future).

The next branch will receive changes to be tested in CI when things
will be hooked up, and may have rewritten history as a consequence of
wanting passing tests on every commit on master.

Git-cinnabar is a git remote helper to interact with mercurial repositories. It allows to clone, pull and push from/to mercurial remote repositories, using git.

Get it on github.

What's new since 0.2.1?

• Don't require core.ignorecase to be set to false on the repository when using a case-insensitive file system. If you did set core.ignorecase to false because git-cinnabar told you to, you can now set it back to true.
• Raise an exception when git update-ref or git fast-import return an error. Silently ignoring those errors could lead to bad repositories after an upgrade from pre-0.1.0 versions on OS X, where the default maximum number of open files is low (256), and where git update-ref uses a lot of lock files for large transactions.
• Updated git to 2.4.0, when building with the native helper.
• When doing git cinnabar reclone, skip remotes with remote.$remote.skipDefaultUpdate set to true.

Git-cinnabar is a git remote helper to interact with mercurial repositories. It allows to clone, pull and push from/to mercurial remote repositories, using git.

Get it on github.

What's new since 0.2.0?

Not much, but this felt important enough to warrant a release, even though the issue has been there since before 0.1.0:

Mercurial can be slower when cloning or pulling a list of "heads" that contain non-topological heads. On repositories like the mercurial repository, it's not so much of a big deal, taking 7s instead of 4s. But on big repositories like mozilla-central, it's taking 23 minutes instead of 2 minutes and 20s (on my machine). And that's with 100% CPU use on the server side.

The problem is that mozilla-central recently merged some old closed heads, such that it now has branch heads that aren't topological heads. Git-cinnabar, until this release, would request those branch heads, leading the server to use the slow path mentioned above. This release works around the issue.

It also fixes an issue pushing to a remote empty mercurial repository.

Git-cinnabar is a git remote helper to interact with mercurial repositories. It allows to clone, pull and push from/to mercurial remote repositories, using git.

Get it on github.

What's new since 0.1.1?

• git cinnabar git2hg and git cinnabar hg2git commands that allow to translate (possibly abbreviated) git sha1s to mercurial sha1s and vice-versa.
• A "native" helper that makes some operations faster. It is not required for git-cinnabar to work, but it can improve performance significantly. Check the Setup instructions in the README file.
• Do not store mercurial metadata when pushing to non-publishing repositories. For Mozilla developers, this means not storing that metadata when pushing to try, which is a good thing when you know each of them makes pulling slower. This behavior can be changed if necessary. Future releases will allow to remove metadata that was created by previous releases but that wouldn't be created with 0.2.0.
• Made the discovery phase of pushes require less round trips (the phase that finds what is common between the local and remote repositories), hopefully making pushing faster.
• Improved logging, which now doesn't require fiddling with the code to get extra logging.
• Made fsck validate more things, and act on more errors.
• Fixed a few edge cases.
• Better handle files with weird names, and that git quotes in its output.
• Extensively tested on the following repositories: mozilla-central, mozilla-beta, mercurial, hg-git, cpython.

What to expect next?

• Allow to push merge commits.
• Improve memory footprint for pushes (currently, it's fairly catastrophic on big repositories ; don't try to push multiple hundreds of commits of a Mozilla-sized repository if you don't have multiple gigabytes of memory available).
• As mentioned above, allow to remove some metadata.
• And more...

If you want to follow the improvements more closely, I encourage you to switch to the `next` branch. I won't push anything there that hasn't been extensively tested on the above mentioned repositories.

And as always, please report any issue you run into.

0.1.1 is a one-bugfix release fixing an issue where git-cinnabar could be confused if commands were started from a subdirectory of the repository. It might be the cause for corruptions leading to issues such as the impossibility to push.

If you do encounter failures please report them. Please also paste the output of git cinnabar fsck.

As you may or may not know, I have been working on this project for quite some time, but actually really started the most critical parts a couple months ago. After having looked for (and chosen) a new name for what was a prototype project, it's now time for a very first release.

So what is this all about?

Cinnabar is the common natural form in which mercury can be found on Earth. It contains mercury sulfide and its powder is used to make the vermillion pigment.

What does that have to do with git?

Hint: mercury.

Git-cinnabar is a git remote helper (you can think of that as a plugin) to interact with mercurial repositories. It allows to clone, pull and push from/to mercurial remote repositories, using git.

Numerous such tools already exist. Where git-cinnabar stands out is that it doesn't use a local mercurial clone under the hood (unlike all the existing other such tools), and is close to an order of magnitude faster to clone a repository like mozilla-central than the git-remote-hg that used to be shipped as a contrib to git.

I won't claim it is exempt of problems and limitations, which is why it's not a 1.0. I'm however confident enough with its state to make the first "official" release.

Get it on github.

If you've been using the prototype, you can actually continue to use that clone and update it. Github conveniently keeps things working after a rename. You can update the remote url if you feel like it, though.

If you are a Gecko developer, you can take a look at a possible workflow.