Working on Your Branch

Now that you have built and activated your virtual development environment, you are ready to use OpenMDAO. If you have not activated your environment, please do so before proceeding. See Activating the Virtual Environment.

The following sections provide information on how to carry out some basic actions in the development environment. You would perform these actions on a branch that you pulled from Launchpad.


In some cases the examples are written from the Linux perspective. Windows users need to replace the / with a \.

Guidelines for Development

We try to follow the PEP 8 style guidelines for Python code, and we use pylint to check for PEP 8 compliance.

Adding New Source Files

If you create new files or directories that you want to be part of OpenMDAO, you must add them to your repository by running the command:

bzr add <filename>

If <filename> is a directory, all files and subdirectories (and their files) within the directory will also be added to the repository, unless they match any of the patterns in the .bzrignore file located in the top level directory of the branch. To add a new pattern for Bazaar to ignore, type:

bzr ignore <pattern>

where <pattern> can be a filename or a wildcard expression, e.g., *.exe.

If you add a file or directory to the repository by mistake, type:

bzr remove <filename> --keep

This will remove the file from the repository but will not delete it.

Committing Changes

After you make changes on your branch, make sure you commit, or record, these changes to your local repository. To see if you have uncommitted changes, type:

bzr status

If there are uncommitted changes, the modified files will be listed. Any files that were not added to the repository will be listed as “unknown.”

When you commit changes, you must add a commit message. To commit and add the message on the command line (inside quotation marks), type:

bzr commit -m "<commit message>"

If you omit the -m and press Enter, your default text editor will open a new file where you must enter the required commit message.

Running Tests

For detailed information on running tests on your branch, please see Testing.

Merging to Your Branch

As you work on your branch, you may want to incorporate any changes that have been made to the trunk since you created your branch. You cannot merge from the trunk to your branch if you have uncommitted changes.

You should be in the top level directory of your branch. To check whether you have uncommitted changes, type:

bzr status

The next step is required only if you have uncommitted changes. You many add a message on the command line (using -m) or press Enter to type the required message using your default text editor.

bzr commit -m "<commit_message>"

Next, you will change directory to go to your virtual development environment:

cd devenv

On Linux or OS X, you must be running Bash to activate your environment. If you are in Bash, omit this next step.


To activate your virtual development environment, type:

. bin/activate

Or, on Windows, type:


If you have doc changes, you can build the docs from scratch, by typing:


To display the docs:


Before merging you should run all the unit tests. You may merge only if all tests pass. To run tests, type:


And finally, to merge from the openmdao trunk to your branch, type:

bzr merge lp:openmdao

- If you have no merge conflicts, you can continue.

It’s a good idea to remove the old virtual environment so that when you rebuild, the correct packages will be used and not leftover packages that may be missing something you need.

To remove the old directory, type:

rm -rf devenv

To build your new virtual dev environment, type:


To change to the dev environment:

cd devenv

On Linux or Mac OS X, you must be running Bash to activate your environment. If you are in Bash, omit this next step.


To activate your virtual development environment, type:

. bin/activate

Or, on Windows, type:


To confirm that all tests still pass, type:


If all tests pass, you may commit the changes from your merge. (This avoids mixing up merge changes with any later changes you make.) Type:

bzr commit -m "<commit_message>"

You are now ready to continue development on your branch.

- If you HAVE a conflict, Bazaar will display not only the changes in files or directories, but it will also indicate the number of conflicts and where they occur. See the following example:

a screen capture from a Linux machine showing a list of changes and conflicts on a branch

Example of Conflicts When Merging

In the above example, the “+N” indicates new files or directories. The “M” indicates modified files or directories. If a file or directory is deleted, “-D” appears before its name. In this example two conflicts must be resolved before proceeding.

If you have a conflict, please refer to Resolving Conflicts in the Bazaar User Guide.

Pushing a Branch Back to Launchpad

The following instructions are for Linux, OS X, and Windows platforms.

First, make sure all of your changes are committed and that the documentation builds successfully (if applicable) and all tests pass.

You will push your branch up to the openmdao repository, but the changes will not become a part of the development trunk until one of the reviewers approves it, and it is merged. Note that your branch may be reviewed by a senior developer and a tech writer (if there are documentation changes).

If your branch is associated with a Trac ticket, the SCM will tag your branch with the related ticket number when she merges it. For more information about submitting a ticket in Trac, go to the OpenMDAO Development page on our website.

On the branch to be pushed, type the following command, replacing userid with your Launchpad userid and replacing branch_name with the name of the branch you are pushing.

bzr push lp:~userid/openmdao/branch_name

Now that your branch is on Launchpad, you can request that it be merged by following the instructions below.

  1. Go to OpenMDAO on Launchpad and log in if you are not logged in already.

  2. Click on the Code tab at the top of the page to go to Bazaar branches of OpenMDAO. On this page you will see the openmdao trunk, which should be the first branch listed. Below that you should see all branches that have been uploaded but are not on the trunk, including the branch that you just pushed up. (You may need to refresh your browser window.)

  3. Click on the name of your branch to take you to the page for that branch. On this new page you will see the command for getting this branch (pulling it down to your work area). Note that you are the owner of the branch; as such, you are the only one who can “push” to it. (If you wanted to collaborate with someone and have your branch available to pull down, you could leave it there and not immediately propose a merge.)

  4. Click on Propose for merging. You will see a new page, Propose branch for merging.

  5. In the Description of the Change box provide the information requested below the box. If your branch is associated with a Trac ticket, and you have already provided detailed information about your changes in Trac (possibly even a test), you may just want to refer to that ticket (e.g., “See Trac ticket 30.”).

  6. When you have completed the description, click the Propose Merge button. (Alternatively you many cancel the merge request at this point.) If you clicked on the Propose Merge button, a new page, Proposal to merge branch, will appear. It shows the proposed branch (your branch name) and what it will merge into (lp:openmdao). Your description of the changes is shown.

    At the bottom of the page is a message that says an updated diff will be available in a few minutes. If you wish to view a graphical interface of the differences, refresh your browser window and a new display will pop up showing the differences between the trunk and your branch (in color). This file may be downloaded and saved if desired.

You have now completed the process for proposing that your branch be merged. In a short time, you will receive a copy of an email that went to the gatekeeper of all merge proposals. The email will show you as the sender, and the subject will be the merge of your branch to openmdao: [Merge]lp:~username/openmdao/branch_name into openmdao. The email will contain the proposal for merge and an attachment showing the differences. (This diff file is just a text file and is not very readable.)

After the proposal for merge has been reviewed, you will get an email from the reviewer indicating whether the proposal was approved or disapproved.

  • If your proposal for merge was approved, you will get an email from after your branch has been merged.
  • If your proposal for merge was disapproved, you can continue working on your branch. (If you have a Trac ticket open, it will be transitioned back to the WORKING state.)