Code Contributions

Introduction

All of the Instant Messaging Freedom related projects use Review Board for handling contributions at reviews.imfreedom.org.

First Time Setup

There are a few things you'll need to set up to be able to submit a code review to these projects. This includes installing RBTools as well as some additional Mercurial configuration.

Install RBTools

The recommended way to install RBTools is via pip and can be done with the following command.

pip3 install --user "RBTools>=3.0"

Once RBTools is installed you need to make sure that rbt is available on your $PATH. To do this, you may need to add $HOME/.local/bin to your $PATH. The exact procedure to do this is dependent on your setup and outside of the scope of this document.

Mercurial Configuration

This configuration for Mercurial is to make your life as a contributor easier. There are a few different ways to configure Mercurial, but these instructions will update your user specific configuration in $HOME/.hgrc.

The first thing we need to do is to install the evolve extension. This extension makes rewriting history safe and we use it extensively in our repositories. You can install it with a simple pip3 install --user hg-evolve. We will enable it below with some other bundled extensions, but you can find more information about it here.

Next you'll want to copy the configuration below and save it in $HOME/.hgrc, making sure to edit the username of course!

[ui]
# Your username will be added to every commit so make sure it's set properly.
# However, this won't be used when your review requests are landed, for that
# you need to make sure your name and email are set properly in reviewboard.
username = Full Name <email@example.com>

# This setting updates a large number of settings for a better user experience,
# and is highly recommended for that reason!!
tweakdefaults = true

[extensions]
# Mercurial has support for extensions and there are a few we want to turn on.
# We do not specify a value which tells Mercurial to look for them in the
# default locations.

# The rebase extension allows us to move a commit. This is very useful when an
# upstreamed change causes some conflict with your local code and will make it
# easier for you to resolve the conflict.
rebase =

# The evolve extension lets you safely edit history.
evolve =

[revsetalias]
# revsetaliases are shortcuts to select commits to operate on.

# This wip revsetalias will select all commits that are on your current branch
# but not on the default branch.
wip = only(.,default)

[alias]
# The lg alias is the same as the normal `hg log` but it will show the graph as
# well as commit phase in its output.
lg = log --graph --template phases

# The wip alias will show every commit between the upstream and your work in
# progress.
wip = log --graph --rev wip

Log in to Review Board

To be able to submit a review request you need to have an account on our JetBrains Hub instance at hub.imfreedom.org. You can create an account here in a number of ways and even turn on two factor authentication.

When logging in to review board, please make sure to use the "login with hub.imfreedom.org" button. Doing so will avoid having to use an application password if you have two factor authentication turned on.

Once you have that account you can use it to login our Review Board instance at reviews.imfreedom.org. Please note, you will have to login via the web interface before being able to use RBTools.

Once you have an account and have logged into our Review Board site, you can begin using RBTools. To get started, you'll need to grab an API token from reviewboard from here, or you can go to <username> -> My Account -> Authentication manually. Copy that API token to your clipboard.

Now in your shell, navigate to a Mercurial clone of one of the Instant Messaging Freedom related projects, then run the following command:

rbt login --api-token <the api token on your clipboard>

Note: this may say "you're already logged in", this is a bug in RBTools and will be fixed in a future version. You should only need to do this once, unless you change your password or have run the rbt logout command.

Creating a New Review Request

Before starting a new review request, you should make sure that your local copy of the repository is up to date. To do so, make sure you are on the default branch via hg update default. Once you are on the default branch, you can update your copy with hg pull --update. Now that you're starting with the most recent code, you can proceed with your contributions.

While it's not mandatory, it is highly recommended that you work on your contributions via a branch. If you don't go this path, you will have issues after your review request is merged. This branch name can be whatever you like as it will not end up in the main repositories, and you can delete it from your local repository after it is merged. See cleanup for more information.

You can create the branch with the following command:

hg branch my-new-branch-name

Now that you have a branch started, you can go ahead and work like you normally would, committing your code at logical times, etc. Once you have some work committed and you are ready to create a new review request, you can type rbt post wip and you should be good to go. This will create a new review request using all of the committed work in your repository and will output something like below.

Review request #403 posted.

https://reviews.imfreedom.org/r/403/
https://reviews.imfreedom.org/r/403/diff/

At this point, your review request has been posted, but it is not yet published. This means no one can review it yet. To do that, you need to go to the URL that was output from your rbt post command and verify that everything looks correct. If this review request fixes any bugs, please make sure to enter their numbers in the bugs field on the right. Also, be sure to review the actual diff yourself to make sure it includes what you intended it to and nothing extra.

Once you are happy with the review request, you can hit the publish button which will make the review request public and alert the reviewers of its creation. Optionally you can pass --open to rbt post in the future to automatically open the draft review in your web browser.

rbt post has a ton of options, so be sure to check them out with rbt post --help. There are even options to automatically fill out the bugs fixed fields among other things.

Updating an Existing Review Request

Typically with a code review, you're going to need to make some updates. However there's also a good chance that your original branching point has changed as other contributions are accepted. To deal with this you'll need to rebase your branch on top of the new changes.

Rebasing, as the name suggests is the act of replaying your previous commits on top of a new base revision. Mercurial makes this pretty easy. First, make sure you are on your branch with hg up my-branch-name. Now you can preview the rebase with hg rebase --dest default --keepbranches --dry-run. We prefer doing a dry-run just to make sure there aren't any major surprises. You may run into some conflicts, but those will have to be fixed regardless.

If everything looks good, you can run the actual rebase with hg rebase --dest default --keepbranches. Again if you run into any conflicts, you will have to resolve them and they will cause the dry-run to fail. Once you have fixed the merge conflicts, you'll then need to mark the files as resolved with hg resolve --mark filename. When you have resolved all of the conflicted files you can continue the rebase with hg rebase --continue. You may run into multiple conflicts, so just repeat until you're done. If you've lost track of where you are in resolving conflicts you can use hg resolve --list to see the current state.

After rebasing you can start addressing the comments in your review and commit them. Once they are committed, you can update your existing review request with rbt post --update. If for some reason rbt can not figure out the proper review request to update, you can pass the number in via rbt post --review-request-id #. Note that when using --review-request-id you no longer need to specify --update.

Just like an initial rbt post, the updated version will be in a draft state until you publish it. So again, you'll need to visit the URL that was output, verify everything, and click the publish button.

Landing a Review Request

This will typically only be done by the maintainers with push access. If you want to test a patch from a review request, please see the Testing Patches Locally section below.

It is HIGHLY recommended that you use a separate clone of the repository in question when you want to land review requests. This makes it much easier to avoid accidentally pushing development work to the canonical repository which makes everyone's life easier. Also, the mainline repositories now auto publish, so if you do not selectively push commits, all of your draft commits will be published. You can name this additional clone whatever you like, but using something like pidgin-clean is a fairly common practice. This makes it easy for you to know that this clone is only meant for landing review requests, and other administrative work like updating the ChangeLog and COPYRIGHT files.

When you are ready to land a review request you need to make sure you are on the proper branch. In most cases this will be the branch named default and can be verified by running the command hg branch. Next you need to make sure that your local copy is up to date. You can do this by running hg pull --update.

Please note, if you run hg pull and then immediately run hg pull --update you will not update to the most recent commit as this new invocation of hg pull has not actually pulled in any new commits. To properly update, you'll need to run hg update instead.

Once your local copy is up to date you can land the review request with rbt land --no-push --review-request-id # where # is the number of the review request you are landing. The --no-push argument is to disable pushing this commit immediately. Most of our configuration already enables this flag for you, but if you're in doubt, please use the --no-push argument.

Once the review request has been landed, make sure to verify that the revision history looks correct, run a test build as well as the unit tests, and if everything looks good, you can continue with the housekeeping before we finally push the new commits.

The housekeeping we need to do entails a few things. If this is a big new feature or bug fix, we should be documenting this in the ChangeLog file for the repository. Please follow the existing convention of mentioning the contributor as well as the issues addressed and the review request number. Likewise, if this is someone's first contribution you will need to add them to the COPYRIGHT file in the repository as well. If you had to update either of these files, review your changes and commit them directly.

Now that any updates to ChangeLog and COPYRIGHT are completed, we can actually start pushing the changes back to the canonical repository. Currently not all of the canonical repositories are publishing repositories so we'll need to manually mark the commits as public. This is easily accomplished with hg phase --public. Note, if you are not using a separate clone of the canonical repository you will need to specify a revision to avoid publishing every commit in your repository. If you run into issues or have more questions about phases see the official documentation.

Now that the changes have been made public, we can finally push to the canonical repository with hg push. Once that is done, you'll also need to go and mark the review request as Submitted in the Review Board web interface.

Testing Patches Locally

Note This section is meant for testing patches for existing review requests. If you are updating a review request, you should be following the Updating an existing review request section above.

If you want to test a patch locally for any reason, you first need to make sure that you are on the target branch for the review request which is listed on the review request page. In most cases this will be the default branch. Regardless you'll need to run hg up branch-name before applying the patch.

Now that you are on the correct branch, you can apply the patch with rbt patch # where # is the id of the review request you want to test. This will apply the patch from the review request to your working copy without committing it.

Once you're done with your testing you can remove the changes with hg revert --no-backup --all. This will return your repository to exactly what it was before the patch was applied. The --no-backup argument says to not save the changes that you are reverting and the --all argument tells Mercurial to revert all files.

Cleaning up a Landed or Discarded Review Request

Whether or not your pull request has been accepted, you probably want to clean it up from your local repository. To do so, you need to update to a branch other than the branch you built it on. In the following example, we're going to remove the branch named my-new-branch-name that we used to create a review request.

If you review request was merged, you can tell Mercurial the revision that has become the successor to your revision. You can do this by running hg log --graph to find the land commit's hash. In the example below, we found a commit has of abc123.

hg up default
hg prune --rev 'branch(my-new-branch-name)' --successor abc123

If you just want to remove the branch and not tell Mercurial why it was deleted, you can just prune the branch entirely without specifying a successor.

hg up default
hg prune --rev 'branch(my-new-branch-name)'

Now, all commits that were on the my-new-branch-name branch will have their contents removed but internally Mercurial keeps track that these revisions have been deleted.

You can repeat this for any other branches you need to clean up, and you're done!