git-upstream is an open source Python application that can be used to keep in sync with upstream open source projects, mainly OpenStack.
The main usecase for this tool is for people who are doing active contributions to repositories that are mirrors of OpenStack repositories, with the intention that most of those contributions will be submitted to review.openstack.org at some point. If you are running a public cloud based on OpenStack, having local changes needed to use it in your environment, you can use git-upstream to stay up to date with the upstream master in a easier way (with respect to using raw git commands).
git-upstream provides new git subcommands to support rebasing of local-carried patches on top of upstream repositories. It provides commands to ease the use of git for who needs to integrate big upstream projects in their environment. The operations are performed using Git commands.
Note: currently git-upstream can be used only for projects that are maintained with Gerrit as it relies on the presence of Change-IDs. Nevertheless, the code is quite modular and can be extended to use any part of commit message (e.g., other headers).
Specifically, current git-upstream version supports the following features
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Single upstream branch import
Your repository is tracking an upstream project and has local changes applied and no other branch is merged in. This can also be applied to tracking upstream packaging branches: e.g., ubuntu/master => ubuntu/saucy-proposed/nova + local packaging changes.
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Multi branch import (upstream branch + additional branches)
In this case, your project tracks an upstream repository, merges in an arbitrary number of branches and applies local carried changes.
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Re-reviewing
Reviewing (w/ Gerrit) of all locally applied changes if desired. git-upstream creates an import branch in a manner that allows it to be fully re-reviewed or merged into master and pushed.
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Detailed logging
git-upstream can output to both console and log file simultaneously. Multiple levels and these are managed separately for log file and console output. This means jobs run by Jenkins can save a detailed log file separately as an artefact while printing status information to the console if those running the jobs don’t wish to have the console spammed with the details.
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Dropping of changes that appear upstream
Compares Change-Id's of changes applied since previous import with those that have appeared on the upstream branch since the last import point.
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Interactive mode
Once the list of changes to be re-applied has been determined (and those to be dropped have been pruned), the tool can open an editor (controlled by your git editor settings) for users to review those changes to be made and allow them to perform further operations such as re-ordering, dropping of obsolete changes, squashing.
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Dropping local changes
It’s always possible for local changes to be superseded by upstream changes, so when these are identified and marked as such, we should drop them.
This can also occur where a change was applied locally, modified when being upstreamed based on review feedback and the resulting differences were ported to the internal as well. While the original change will be automatically dropped, also useful to drop the additional ported changes automatically if possible, rather than have it cause conflicts.
The name of this tool includes the "git-" prefix because of the Git naming convention that a Git subcommand must have. So, as git-review (usually invoked with "git review [...]"), this tool can be invoked using "git upstream [...]".
That said, and even if git-upstream currently uses Change-Ids, it is not strictly related to git-review. In other words, git-review can (and most of the time will) be used without even knowing about git-upstream existence.
At the time of writing, there are two ways to install git-upstream: cloning its git repository or using pip.
git clone https://github.com/stackforge/git-upstream.git
cd git-upstream
# Install git-upstream itself
python setup.py installpip install git-upstreamSee also https://pypi.python.org/pypi/git-upstream
Please see USAGE.md
Import code from specified upstream branch. Creates an import branch from the specified upstream branch, and optionally merges additional branches given as arguments. Current branch, unless overridden by the --into option, is used as the target branch from which a list of changes to apply onto the new import is constructed based on the the specified strategy. Once complete it will merge and replace the contents of the target branch with those from the import branch, unless --no-merge is specified.
git upstream import [-h] [-d] [-i] [-f] [--merge] [--no-merge]
[-s <strategy>] [--into <branch>]
[--import-branch <import-branch>]
[<upstream-branch>] [<branches> [<branches> ...]]
positional arguments:
<upstream-branch> Upstream branch to import. Must be specified if you
wish to provide additional branches.
<branches> Branches to additionally merge into the import branch
using default git merging behaviour
optional arguments:
-h, --help show this help message and exit
-d, --dry-run Only print out the list of commits that would be
applied.
-i, --interactive Let the user edit the list of commits before applying.
-f, --force Force overwrite of existing import branch if it
exists.
--merge Merge the resulting import branch into the target
branch once complete
--no-merge Disable merge of the resulting import branch
-s <strategy>, --strategy <strategy>
Use the given strategy to re-apply locally carried
changes to the import branch. (default: drop)
--into <branch> Branch to take changes from, and replace with imported
branch.
--import-branch <import-branch>
Name of import branch to use
Mark a commit as dropped. Marked commits will be skipped during the upstream rebasing process.
See also the "git upstream import" command.
git upstream drop [-h] [-a <author>] <commit>
positional arguments:
<commit> Commit to be marked as dropped
optional arguments:
-h, --help show this help message and exit
-a <author>, --author <author>
Git author for the mark
Commits will be marked with git notes in the namespace refs/notes/upstream-merge.
To list of commit id marked with a note, run git notes --ref refs/notes/upstream-merge.
To show a specific note run git notes --ref refs/notes/upstream-merge show <marked commit sha1>
As drop uses git notes to mark commits that have to be skipped during import, notes should be present on the cloned copy of your repository. Thus, if you are going to create notes on a system and perform the actual import on a different system, notes must be present on the latter.
You can push notes directly to git repository on the target system or push them in a different repository and then pull notes from your target system.
Mark a commit as superseded by a set of change-ids. Marked commits will be skipped during the upstream rebasing process only if all the specified change-ids are present in <upstream-branch> during import.
If you want to unconditionally drop a commit, use the drop command instead.
See also the "git upstream import" command.
git upstream supersede [-h] [-f] [-u <upstream-branch>]
<commit> <change id> [<change id> ...]
positional arguments:
<commit> Commit to be marked as superseded
<change id> Change id which makes <commit> obsolete. The change id
must be present in <upstream-branch> to drop <commit>.
If more than one change id is specified, all must be
present in <upstream-branch> to drop <commit>
optional arguments:
-h, --help show this help message and exit
-f, --force Apply the commit mark even if one or more change ids
could not be found. Use this flag carefully as commits
will not be dropped during import command execution as
long as all associated change ids are present in the
local copy of the upstream branch
-u <upstream-branch>, --upstream-branch <upstream-branch>
Search change ids values in <upstream-branch> branch
(default: upstream/master)
This command doesn't perform the actual drop. Commits to be dropped during the next import, will be marked with git notes in the namespace refs/notes/upstream-merge.
There is no need to retain notes after an import dropped the correspondent commits, of course it doesn't harm keeping them either.
To list of commit id marked with a note, run git notes --ref refs/notes/upstream-merge.
To show a specific note run git notes --ref refs/notes/upstream-merge show <marked commit sha1>.
As supersede uses git notes to mark commits that have to be skipped during import, notes should be present on the cloned copy of your repository. Thus, if you are going to create notes on a system and perform the actual import on a different system, notes must be present on the latter.
You can push notes directly to git repository on the target system or push them in a different repository and then pull notes from your target system.
Please see KNOWN-ISSUES.md.
git-upstream was written by Darragh Bailey [email protected].
Thanks to Aleksander Korzynski and Stanisław Pitucha for taking the original design spec and some basic manual steps and experimenting with initial implementations.
To Davide Guerri, for picking up a rough python tool and turning it into something that was actually usable.
Also to Jon Paul Sullivan and Monty Taylor to listening and providing a sounding board for different approaches.
And finally to Coleman Corrigan among numerous others who acted as willing guinea pigs for the original manual approach.
Hope this eventually helped save you time and some hair.