# Gerrit Code Review - Core Plugins

version v3.4.4

## What are core plugins?

Core plugins are plugins that are packaged within the Gerrit war file. This means during the Gerrit initialization they can be easily installed without downloading any additional files.

To make working with core plugins easy, they are linked as Git submodules in the `gerrit` repository. E.g. this means they can be easily cloned together with Gerrit.

All core plugins are developed and maintained by the Gerrit maintainers and everyone can contribute to them.

Adding a new core plugin feature that is large or complex requires a design doc (also see design-driven contribution process). The engineering steering committee (ESC) is the authority that approves the design docs. The ESC is also in charge of adding and removing core plugins.

Non-Gerrit maintainers cannot have Owner permissions for core plugins.

## Which core plugins exist?

See here.

### Criteria for Core Plugins

To be considered as a core plugin, a plugin must fulfill the following criteria:

1. License:

   The plugin code is available under the Apache License Version 2.0.

2. Hosting:

   The plugin development is hosted on the gerrit-review Gerrit Server.

3. Scope:

   The plugin functionality is Gerrit-related, has a clear scope and does not conflict with other core plugins or existing and planned Gerrit core features.

4. Relevance:

   The plugin functionality is relevant to a majority of the Gerrit community:

   - An out of the box Gerrit installation would seem like it is missing something if the plugin is not installed.

   - It’s expected that most sites would use the plugin.

   - Multiple parties (different organizations/companies) already use the plugin and agree that it should be offered as core plugin.

   - If the same or similar functionality is provided by multiple plugins, the plugin is the clear recommended solution by the community.

   Whether a plugin is relevant to a majority of the Gerrit community must be discussed on a case-by-case basis. In case of doubt, it’s up to the engineering steering committee to make a decision.

5. Code Quality:

   The plugin code is mature and has a good test coverage. Maintaining the plugin code creates only little overhead for the Gerrit maintainers.

6. Documentation:

   The plugin functionality is fully documented.

7. Ownership:

   Existing plugin owners which are not Gerrit maintainers must agree to give up their ownership. If the current plugin owners disagree, forking the plugin is possible, but this should happen only in exceptional cases.

## Process to make a plugin a core plugin

Anyone can propose to make a plugin a core plugin, but to be accepted as core plugin the plugin must fulfill certain criteria.

1. Propose a plugin as core plugin:

   File a Core Plugin Request in the issue tracker and provide the information that is being asked for in the request template.

2. Community Feedback:

   Anyone can comment on the issue to raise concerns or to support the request. The issue should stay open for at least 10 calendar days so that everyone in the community has a chance to comment.

3. ESC Decision:

   The ESC should discuss the request and reject/approve it or ask for further information that the reporter or commenters should provide.

   Any decision must be based on the criteria that core plugins are expected to fulfill and should take the feedback from the community into account.

   Accepting the request is only possible if the issue was open for at least 10 calendar days (see 2., this gives the community time to comment).

   When the ESC approves/rejects the request a summary of the reasons for the decision should be added to the issue.

   If a request is rejected, it’s possible to ask for a revalidation if the concerns that led to the rejection have been addressed (e.g. the plugin was rejected due to missing tests, but tests have been added afterwards).

4. Add plugin as core plugin:

   If the request was accepted, a Gerrit maintainer should add the plugin as core plugin:

   - Host the plugin repo on gerrit-review.

   - Ensure that the plugin repo inherits from the Public-Plugins repo.

   - Remove all permissions on the plugin repo (the inherited permissions from `Public-Plugins` should be enough). Especially make sure that there are no Owner, Direct Push, Submit or Code-Review+2 permissions for non-Gerrit maintainers.

   - Create a component for the plugin in Monorail and assign all issues that already exist for the plugin to this component.

   - Add the plugin as Git submodule.

   - Register the plugin as core plugin in plugins.bzl.

   - Announce the new core plugin in the project news.

### Removing Core Plugins

A core plugin could be subject to NOT be considered core anymore if:

1. Does not respect the license:

   The plugin code or the libraries used are not following anymore the Apache License Version 2.0.

2. Is out of scope:

   The plugin functionality has gone outside the Gerrit-related scope, has a clear scope or conflict with other core plugins or existing and planned Gerrit core features.

   Note | The plugin would need to remain core until the planned replacement gets implemented. Otherwise the feature is likely missing between the removal and planned implementation times.

3. Is not relevant:

   The plugin functionality is no more relevant to a majority of the Gerrit community:

   - An out of the box Gerrit installation won’t be missing anything if the plugin is not installed.

   - It isn’t anymore used by most sites.

   - Multiple parties (different organizations/companies) have abandoned the use of the plugin and agree that it should not be anymore a core plugin.

   - If the same or similar functionality is provided by multiple plugins, the plugin is not a clear recommended solution anymore by the community.

   - Whether a plugin is no more relevant to a majority of the Gerrit community must be discussed on a case-by-case basis. In case of doubt, it’s up to the engineering steering committee to make a decision.

4. Degraded code quality:

   The plugin code maintenance is lacking and has not anymore good test coverage. Maintaining the plugin code creates a significant overhead for the Gerrit maintainers.

5. Outdated documentation:

   The plugin functionality documented is significantly outdated.

Part of Gerrit Code Review