# Contributing to Metacat :tada: First off, thanks for contributing!:tada: - [Types of contributions](#types-of-contributions) - [Pull Requests](#pull-requests) - [Development Workflow](#development-workflow) - [Release process](#release-process) - [Testing](#testing) - [Code style](#code-style) - [Contributor license agreement](#contributor-license-agreement) ## Types of contributions We welcome all types of contributions, including bug fixes, feature enhancements, bug reports, documentation, graphics, and many others. You might consider contributing by: - Report a bug or request a new feature in our [issue tracker](https://github.com/NCEAS/metacat/issues) - Fix a bug and contribute the code with a Pull Request - Write or edit some documentation - Develop a screencast tutorial - Answer questions on our mailing list or Slack team - ... Metacat is an open source project, and we welcome full participation in the project. Contributions are reviewed and suggestions are made to increase the value of Metacat to the community. We strive to incorporate code, documentation, and other useful contributions quickly and efficiently while maintaining a high-quality repository software product. ## Pull Requests We use the pull-request model for contributions. See [GitHub's help on pull-requests](https://help.github.com/articles/about-pull-requests/). In short: - add an [issue](https://github.com/NCEAS/metacat/issues) describing your planned changes, or add a comment to an existing issue; - on GitHub, fork the [metacat repository](https://github.com/NCEAS/metacat) - on your computer, clone your forked copy of the metacat repository - checkout a development branch and commit your changes - push your branch to your forked repository, and submit a pull-request - go through the review process, making changes until your pull-request can be merged - describe your changes in the issue, and close your issue. ## Development Workflow Development is managed through the git repository at https://github.com/NCEAS/metacat. The repository is organized into several branches, each with a specific purpose. **main**. The `main` branch represents a stable branch that is constantly maintained in a state ready for release. Any unreleased code changes on the main branch represent changes that have been tested and staged for the next release. When a set of features are mature and tested and ready for release, they are merged onto the `main` branch to await the next release. The tip of the main branch always represents the set of features that have been staged for the next release. The version number in all configuration files and the README on the main branch follows [semantic versioning](https://semver.org/) and should always be set to either: - the current release version, if the HEAD of `main` still matches the HEAD of `releases`. For example, `2.8.5`. - the planned next release number with a `beta` designator or release candidate `rc` designator appended as appropriate. For example, `2.8.6-beta1` or `2.9.0-rc1`. **releases**. Releases are merged from the `main` branch to the `releases` branch, and the resulting commit is tagged with the release tag (e.g., `2.4.0`). The tip of the `releases` branch always reflects the most recent release of the software. **develop**. Development takes place on a single branch for integrated development and testing of the set of features targeting a particular release. Commits should only be pushed to this branch once they are ready to be deployed to production immediately after being pushed. **feature**. to isolate development on a specific set of capabilities, especially if it may be disruptive to other developers working on the main `develop` branch, feature branches should be created. Feature branches are named with a prefix of `feature` and should include a short descriptive label reflecting their purpose. For example, `feature-new-search` may be a branch name for a feature related to a new search tool. You may also want to include the release version that you are targeting, such `feature-2.11.2-new-search`. You may also want to include the issue number that describes the feature, such as `feature-#1456-new-search`. All feature branches should be frequently merged with changes from `develop` to ensure that the feature branch stays up to date with other features that have been tested and are awaiting release. Thus, each `feature-*` branch represents an opportunity for integration testing of the set of features intended to work together for a particular release. **dev-X.X**. Development branches named after their minor version number can be used when a patch release needs to be created that is behind the main **develop** branch. ### Development flow overview ![](docs/dev/images/nceas-dev-flow.png) ## Release process The release process starts with integration testing in a `develop` branch. Once all changes that are desired in a release are merged into the `develop` branch, we run the full set of tests on a clean checkout of the `develop` branch. Second, create a pull request to merge those changes from the `metacat/develop` branch to the `metacat/main` branch. This pull request should be done from the `develop` branch within the Metacat repository in order to make it simple for others to review the changes, and to maintain a record of the development branch commits. This pull request will be reviewed by another developer, and, after issues and feedback have been resolved, the pull request can be merged into main. This cycle can be repeated multiple times until all features have been tested and merged into main. At this point, if all features for the planned release have been merged to main, then the main branch can be merged to the `releases` branch, and tagged with the new release tag for that release. At this point, the tip of the `releases` branch will reflect the new release and the main branch is ready for work on the next release. ## Testing **Unit and integration tests**. Metacat has a full suite of unit tests and integration tests in the `tests` subdirectory. Any new code developed should include a robust set of unit tests for each public method, as well as integration tests from new feature sets. Tests should fully exercise the feature to ensure that it responds correctly to both good data inputs as well as various classes of corrupt or bad data. All tests should pass before a `develop` branch is merged to main, and all tests should pass before the `main` branch is merged to `releases` and tagged for a release. **Continuous integration**. Metacat is built upon every commit through the Jenkins system for [continuous integration at DataONE](https://purl.dataone.org/integration). Both the `releases` and `main` branch are built and tested, and the current development branch is built as well. ## Code style Code should be written to professional standards to enable clean, well-documented, readable, and maintainable software. While there has been significant variablility in the coding styles applied historically, new contributions should strive for clean code formatting. Some of the guidelines we follow include: **Java**. For Java code, follow the [Google Java Style Guide](https://google.github.io/styleguide/javaguide.html), with the single exception that indentation is performed with 4 spaces rather than 2. When working on a class that does not follow the conventions, strive to reformat that code module in a single isolated code commit before starting other code changes. **Javadoc**. All Java code should be fully documented with JavaDoc comments. Special attention should be paid to documentation of the public API for classes. Documentation should explain both what the code does, but also why it does it in a particular way when appropriate. Class and method documentation should be written to provide sufficient context for people that are not intimately familiar with the rest of the code. Class-level documentation often is strengthened through explaining the role of the class in the architecture. Avoid using tautological definitions that reuse the name of a class or method in its definition. And please be complete. ## Contributor license agreement In order to clarify the intellectual property license granted with Contributions from any person or entity, you agree to a Contributor License Agreement ("CLA") with the Regents of the University of California (hereafter, the "Regents"). 1. Definitions. "You" (or "Your") shall mean the copyright owner or legal entity authorized by the copyright owner that is making this Agreement with the Regents. For legal entities, the entity making a Contribution and all other entities that control, are controlled by, or are under common control with that entity are considered to be a single Contributor. For the purposes of this definition, "control" means (i) the power, direct or indirect, to cause the direction or management of such entity, whether by contract or otherwise, or (ii) ownership of fifty percent (50%) or more of the outstanding shares, or (iii) beneficial ownership of such entity. "Contribution" shall mean any original work of authorship, including any modifications or additions to an existing work, that is intentionally submitted by You to the Regents for inclusion in, or documentation of, any of the products owned or managed by the Regents (the "Work"). For the purposes of this definition, "submitted" means any form of electronic, verbal, or written communication sent to the Regents or its representatives, including but not limited to communication on electronic mailing lists, source code control systems, and issue tracking systems that are managed by, or on behalf of, the Regents for the purpose of discussing and improving the Work, but excluding communication that is conspicuously marked or otherwise designated in writing by You as "Not a Contribution." 2. Grant of Copyright License. Subject to the terms and conditions of this Agreement, You hereby grant to the Regents and to recipients of software distributed by the Regents a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Your Contributions and such derivative works. 3. Grant of Patent License. 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You represent that Your Contribution submissions include complete details of any third-party license or other restriction (including, but not limited to, related patents and trademarks) of which you are personally aware and which are associated with any part of Your Contributions.