If you are looking for something to work on, or need some expert assistance in debugging a problem or working out a fix to an issue, our community is always eager to help. We hang out on various developer meetings, IRC (#automotive on freenode.net) and the mailing lists. We will be glad to help. The only silly question is the one you don't ask. Questions are in fact a great way to help improve the project as they highlight where our documentation could be clearer.
If you are a user and you have found a bug, please submit an issue using JIRA. Before you create a new JIRA issue, please try to search the existing items to be sure no one else has previously reported it. If it has been previously reported, then you might add a comment that you also are interested in seeing the defect fixed.
If it has not been previously reported, create a new JIRA. Please try to provide sufficient information for someone else to reproduce the issue. One of the project's maintainers should respond to your issue within 24 hours. If not, please bump the issue with a comment and request that it be reviewed.
Submitting your fix
If you just submitted a JIRA for a bug you've discovered, and would like to provide a fix, we would welcome that gladly! Please assign the JIRA issue to yourself, then you can submit a change request (CR).
NOTE: If you need help with submitting your first CR, we have created a brief tutorial for you.
Fixing issues and working stories
Review the open issue list and find something that interests you. It is wise to start with something relatively straight forward and achievable, and that no one is already assigned. If no one is assigned, then assign the issue to yourself. Please be considerate and rescind the assignment if you cannot finish in a reasonable time, or add a comment saying that you are still actively working the issue if you need a little more time.
Reviewing submitted Change Requests (CRs)
Another way to contribute and learn about Automotive Grade Linux is to help the maintainers with the review of the CRs that are open. Indeed maintainers have the difficult role of having to review all the CRs that are being submitted and evaluate whether they should be merged or not. You can review the code and/or documentation changes, test the changes, and tell the submitters and maintainers what you think. Once your review and/or test is complete just reply to the CR with your findings, by adding comments and/or voting. A comment saying something like "I tried it on system X and it works" or possibly "I got an error on system X: xxx " will help the maintainers in their evaluation. As a result, maintainers will be able to process CRs faster and everybody will gain from it.
Just browse through the open CRs on Gerrit to get started.
Making Feature/Enhancement Proposals
Review JIRA to be sure that there isn't already an open (or recently closed) proposal for the same function. If there isn't, to make a proposal we recommend that you open a JIRA Epic, Story or Improvement, whichever seems to best fit the circumstance and link or inline a "one pager" of the proposal that states what the feature would do and, if possible, how it might be implemented. It would help also to make a case for why the feature should be added, such as identifying specific use case(s) for which the feature is needed and a case for what the benefit would be should the feature be implemented. Once the JIRA issue is created, and the "one pager" either attached, inlined in the description field, or a link to a publicly accessible document is added to the description, send an introductory email to the agl-dev community mailing list linking the JIRA issue, and soliciting feedback.
Discussion of the proposed feature should be conducted in the JIRA issue itself, so that we have a consistent pattern within our community as to where to find design discussion.
Getting the support of three or more of the AGL maintainers for the new feature will greatly enhance the probability that the feature's related CRs will be merged.
What makes a good change request?
One change at a time. Not five, not three, not ten. One and only one. Why? Because it limits the blast area of the change. If we have a regression, it is much easier to identify the culprit commit than if we have some composite change that impacts more of the code.
Include a link to the JIRA story for the change. Why? Because a) we want to track our velocity to better judge what we think we can deliver and when and b) because we can justify the change more effectively. In many cases, there should be some discussion around a proposed change and we want to link back to that from the change itself.
Include unit and integration tests (or changes to existing tests) with every change. This does not mean just happy path testing, either. It also means negative testing of any defensive code that it correctly catches input errors. When you write code, you are responsible to test it and provide the tests that demonstrate that your change does what it claims. Why? Because without this we have no clue whether our current code base actually works.
Minimize the lines of code per CR. Why? If you send a 1,000 or 2,000 LOC change, how long do you think it takes to review all of that code? Keep your changes to < 200-300 LOC, if possible. If you have a larger change, decompose it into multiple independent changess. If you are adding a bunch of new functions to fulfill the requirements of a new capability, add them separately with their tests, and then write the code that uses them to deliver the capability. Of course, there are always exceptions. If you add a small change and then add 300 LOC of tests, you will be forgiven;-) If you need to make a change that has broad impact or a bunch of generated code (protobufs, etc.). Again, there can be exceptions.
NOTE: Large change requests, e.g. those with more than 300 LOC are more likely than not going to receive a -2, and you'll be asked to refactor the change to conform with this guidance.
Do not stack change requests (e.g. submit a CR from the same local branch as your previous CR) unless they are related. This will minimize merge conflicts and allow changes to be merged more quickly. If you stack requests your subsequent requests may be held up because of review comments in the preceding requests.
Write a meaningful commit message. Include a meaningful 50 (or less) character title, followed by a blank line, followed by a more comprehensive description of the change. Each change MUST include the JIRA identifier corresponding to the change (e.g. [SPEC-1234]). This can be in the title but should also be in the body of the commit message. See the complete requirements for an acceptable change request.
NOTE: That Gerrit will automatically create a hyperlink to the JIRA item.
Bug-AGL: [SPEC-<JIRA-ID>] .... Fix [SPEC-<JIRA-ID>] ....
Finally, be responsive. Don't let a change request fester with review comments such that it gets to a point that it requires a rebase. It only further delays getting it merged and adds more work for you - to remediate the merge conflicts.
We have tried to make it as easy as possible to make contributions. This applies to how we handle the legal aspects of contribution.
We simply ask that when submitting a patch for review, the developer must include a sign-off statement in the commit message. This is done to ensure that the author of the change adhere to follow DCO.
Signed-off-by: John Doe <email@example.com>
You can include this automatically when you commit a change to your local git
git commit -s.