How to Contribute to ManifoldCF
"Contributing" to an Apache project is about more than just writing code – it's about doing what you can to make the project better. There are lots of ways to contribute. New connectors and authorities are welcome. Documentation and tests are equally as important. New features are worthy of proposal and discussion. And last, simple bug fixes are always helpful.
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Contributors should join the ManifoldCF mailing lists. In particular:
- the user list (to help others)
- The commit list (to see changes as they are made)
- The dev list (to join discussions of changes)
Please keep discussions about ManifoldCF on list so that everyone benefits. Emailing individual committers with questions about specific ManifoldCF issues is discouraged. See http://people.apache.org/~hossman/#private_q.
Contributing Code (Features, Big Fixes, Tests, etc...)
This section identifies the ''optimal'' steps community member can take to submit a changes or additions to the ManifoldCF code base. This can be new features, bug fixes optimizations of existing features, or tests of existing code to prove it works as advertised (and to make it more robust against possible future changes).
Please note that these are the "optimal" steps, and community members that don't have the time or resources to do everything outlined on this below should not be discouraged from submitting their ideas "as is" per "Yonik Seeley's (Solr committer) Law of Patches" ...
A half-baked patch in Jira, with no documentation, no tests
and no backwards compatibility is better than no patch at all.
Just because you may not have the time to write unit tests, or cleanup backwards compatibility issues, or add documentation, doesn't mean other people don't. Putting your patch out there allows other people to try it and possibly improve it.
Getting the source code
First of all, you need the ManifoldCF source code.
Get the source code on your local drive using SVN. Most development is done on the "trunk":
> svn checkout http://svn.apache.org/repos/asf/manifoldcf/trunk mcf-trunk
Note that committers have to use https instead of http here, but http is fine for read-only access to the trunk code.
Before you start, you should send a message to the ManifoldCF developer mailing list (Note: you have to subscribe before you can post), or file a bug in Jira. Describe your proposed changes and check that they fit in with what others are doing and have planned for the project. Be patient, it may take folks a while to understand your requirements. In the end, you will need to attach your patch to a Jira ticket, so one of these must be created by either you or someone else that covers your work.
Modify the source code and add some (very) nice features using your favorite IDE, or no IDE at all.
But take care about the following points
- All public classes and methods should have informative Javadoc comments.
- Code should be formatted according to Sun's conventions, with one exception:
- indent two spaces per level, not four.
- Contributions should pass existing unit tests.
- New unit tests should be provided to demonstrate bugs and fixes.
- Modify the CHANGES.txt file in the top directory to include your change and the associated Jira ticket number.
Generating a patch
A "patch file" is the format that all good contributions come in. It bundles up everything that is being added, removed, or changed in your contribution. Here's how to generate one.
Please make sure that all unit tests succeed before constructing your patch. The easiest way to do this is via ant.
If you have a PostgreSQL instance installed, you might also want to run the PostgreSQL version of the tests.
The "build" will fail if there are test errors, which is a sign that there is something wrong that you should investigate. Please, read carefully the errors messages and check your code.
Creating the patch file
Check to see what files you have modified with:
Add any new files with:
svn add src/.../MyNewClass.java
Don't forget to attach the standard V2.0 Apache license header to any new files!
Subversion's "add" command only modifies your local copy, so it does not require commit permissions. By using "svn add", your entire contribution can be included in a single patch file, without needing to submit a separate set of "new" files.
Edit the ''CHANGES.txt'' file, adding a description of your change, including the bug number it fixes.
In order to create a patch, just type the following from the root of the trunk directory hierarchy:
svn diff > CONNECTORS-xxx.patch
This will report all modifications done on ManifoldCF sources on your local disk and save them into the ''CONNECTORS-xxx.patch'' file. Instead of 'xxx', use the actual Jira ticket number.
Read the patch file. Make sure it includes ONLY the modifications required to fix a single issue.
Please do not:
- reformat code unrelated to the bug being fixed: formatting changes should be separate patches/commits.
- comment out code that is now obsolete: just remove it.
- insert comments around each change, marking the change: folks can use subversion to figure out what's changed and by whom.
- make things public which are not required by end users.
- try to adhere to the coding style of files you edit;
- comment code whose function or rationale is not obvious;
- update the documentation, which is found under ''site/src''.
Contributing your work
Finally, patches should be attached to a bug report in Jira. Always remember to check the radio button that grants the license rights to the patch to the Apache Software Foundation; if that button is not checked, then we cannot use your patch! Also, if you are revising an existing patch, please re-use the exact same name as the previous attachment, Jira will "grey out" the older versions so it's clear which version is the newest.
Please be patient. Committers are busy people too. If no one responds to your patch after a few days, please make friendly reminders. Please incorporate others' suggestions into into your patch if you think they're reasonable. Finally, remember that even a patch that is not committed is useful to the community.
Review/Improve Existing Patches
If there's a Jira issue that already has a patch you think is really good, and works well for you – please add a comment saying so. If there's room for improvement (more tests, better javadocs, etc...) then make the changes and attach it as well. If a lot of people review a patch and give it a thumbs up, that's a good sign for committers when deciding if it's worth spending time on the patch – and if other people have already put in effort to improve the docs/tests for a patch, that helps even more.
Applying a patch
From the base directory (assuming that is where the patch is generated from), run:
patch -p 0 -i <PATH TO PATCH> [--dry-run]
The following resources may prove helpful when developing ManifoldCF contributions. (These are not an endorsement of any specific development tools). Note: These are the same code styles that Lucene and Solr use.