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Difference between revisions of "EGit/Contributor Guide"

m (changed url of jetty 7.6 which has been archived)
(Option 2: Install from Orbit P2 Repository: Add Commons Compress)
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= Development IDE Configuration =
 
= Development IDE Configuration =
  
EGit and JGit have Java 5.0 and Eclipse Platform 3.5 as minimum requirements, so dependencies to newer Java and platform versions must be avoided.
+
== Tools ==
  
We are using ''PDE/API Tools Environment Descriptions'' (see changes for [https://git.eclipse.org/r/#/c/4785/ JGit] and [https://git.eclipse.org/r/#/c/4365/ EGit]) to facilitate detecting code which isn't working on Java 5. Install ''PDE/API Tools Environment Descriptions'' from the release train repository to enable that (available starting with Indigo), see [[Execution_Environments#Installing_Execution_Environment_Descriptions|Installing Execution Environment Descriptions]].
+
To install all the necessary tools to work on EGit/JGit, there is a [http://git.eclipse.org/c/egit/egit.git/tree/tools/egit-developer-tools.p2f egit-developer-tools.p2f] file which you can use:
 +
 
 +
* File > Import > Install > Install Software Items from File
 +
* Browse...
 +
** Go to the location of your egit repository, open the ''tools'' directory and select ''egit-developer-tools.p2f''
 +
* All the items you don't already have should be selected automatically
 +
* Finish the wizard
 +
* Restart
 +
 
 +
== Java Requirements ==
 +
 
 +
EGit and JGit have Java 5.0 and Eclipse Platform 3.7 as minimum requirements, so dependencies to newer Java and platform versions must be avoided.
 +
 
 +
We are using ''PDE/API Tools Environment Descriptions'' (see changes for [https://git.eclipse.org/r/#/c/4785/ JGit] and [https://git.eclipse.org/r/#/c/4365/ EGit]) to facilitate detecting code which isn't working on Java 5. If you followed the instructions in the ''Tools'' section above, the necessary descriptions should already be installed. Otherwise install ''PDE/API Tools Environment Descriptions'' from the release train repository, see [[Execution_Environments#Installing_Execution_Environment_Descriptions|Installing Execution Environment Descriptions]].
  
 
Alternatively, add both a Java5 and a Java 6 SDK to your workspace. Do this in Window/Preferences -> Java/Installed JREs. Then configure your Execution Environments so that J2SE-1.5 refer to a Java 5 SDK and JavaSE-1.6 refer to a Java 6 installation.
 
Alternatively, add both a Java5 and a Java 6 SDK to your workspace. Do this in Window/Preferences -> Java/Installed JREs. Then configure your Execution Environments so that J2SE-1.5 refer to a Java 5 SDK and JavaSE-1.6 refer to a Java 6 installation.
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* Protocol Buffers
 
* Protocol Buffers
 
* Apache Jakarta log4j Plug-in
 
* Apache Jakarta log4j Plug-in
 +
* Apache Commons Compress
 
* Hamcrest Library of Matchers
 
* Hamcrest Library of Matchers
  
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</pre>
 
</pre>
  
If you wan to build EGit for the specific Galileo platform, consider using the <code>platform-galileo</code> maven profile:
+
If you wan to build EGit for the specific Indigo platform, consider using the <code>platform-indigo</code> maven profile:
  [~/src/egit] $ mvn -P platform-galileo clean install
+
  [~/src/egit] $ mvn -P platform-indigo clean install
 +
 +
For EGit version 2.1 and earlier, 4 such platform profiles are available: <code>platform-galileo</code> (Eclipse 3.5), <code>platform-helios</code> (Eclipse 3.6), <code>platform-indigo</code> (Eclipse 3.7) and <code>platform-juno</code> (Eclipse 4.2). As of EGit 2.2, older platforms are no longer supported, therefore only <code>platform-indigo</code> (Eclipse 3.7) and <code>platform-juno</code> (Eclipse 4.2) are available.
  
4 such platform profiles are currently available: <code>platform-galileo</code> (Eclipse 3.5), <code>platform-helios</code> (Eclipse 3.6), <code>platform-indigo</code> (Eclipse 3.7) and <code>platform-juno</code> (Eclipse 4.2).
+
Upon a successful build, a p2 update site should be generated inside ''egit/org.eclipse.egit.repository/target/repository''. If not, make sure the target platform has been downloaded from within Eclipse (Windows>Preferences>Plug-in Development>Target Platform). The default target platform defined in the maven build is currently Eclipse 4.2.
  
 
== FindBugs and PMD ==
 
== FindBugs and PMD ==
Line 251: Line 267:
  
 
The JGit projects have API tooling enabled. In order to use PDE API tools to get assistance with maintaining API changes and additions you need to set an API baseline:
 
The JGit projects have API tooling enabled. In order to use PDE API tools to get assistance with maintaining API changes and additions you need to set an API baseline:
* download the p2 repository for the latest EGit release (which includes the JGit artifacts, at the moment the latest release is 1.3.0) to a local folder, e.g. <code>~/egit-releases/updates-1.3</code>, find the p2 repository URLs [http://wiki.eclipse.org/EGit/FAQ#Where_can_I_find_older_releases_of_EGit.3F here]
+
* download the p2 repository for the latest EGit release (which includes the JGit artifacts) to a local folder, e.g. <code>~/egit-releases/updates-2.2</code>, find the p2 repository URLs [http://wiki.eclipse.org/EGit/FAQ#Where_can_I_find_older_releases_of_EGit.3F here] and see [http://wiki.eclipse.org/Equinox_p2_Repository_Mirroring#Mirroring_Artifacts mirroring artifacts] for a way to download the repository
 
* in Eclipse click "Preferences > Plug-In Development > API Baselines", click "Add Baseline..." and define a new baseline (e.g. egit-1.3) and point it to the local copy of the corresponding EGit p2 repository.
 
* in Eclipse click "Preferences > Plug-In Development > API Baselines", click "Add Baseline..." and define a new baseline (e.g. egit-1.3) and point it to the local copy of the corresponding EGit p2 repository.
 
* the API tools will then raise warning/errors for all detected problems and provide quick fixes helping to resolve these problems
 
* the API tools will then raise warning/errors for all detected problems and provide quick fixes helping to resolve these problems
Line 353: Line 369:
 
  mvn -P skip-ui-tests clean install
 
  mvn -P skip-ui-tests clean install
  
'''Note:''' since SWTBot isn't yet ported to Eclipse 4.2 the UI tests can't be executed yet on Eclipse 4.2 (see SWTBot bugs [https://bugs.eclipse.org/bugs/show_bug.cgi?id=375598 375598] and [https://bugs.eclipse.org/bugs/show_bug.cgi?id=384621 384621]).
+
'''Note:''' since the SWTBot port to Eclipse 4.2 isn't yet perfect [1] a few UI tests fail on Eclipse 4.2.
 +
 
 +
[1] https://bugs.eclipse.org/bugs/show_bug.cgi?id=385527
  
 
== Auxilary testing tools ==
 
== Auxilary testing tools ==
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Signed-off-by: Your Name <your.email@example.org>
 
Signed-off-by: Your Name <your.email@example.org>
 
</pre>
 
</pre>
 +
 +
== Copyright ==
 +
 +
When contributing patches, you have to update the copyright section at the beginning of the file if there is one. Please follow the style that is already present in the file. Some examples follow.
 +
 +
When there is only one copyright present (from a person or a company), like this:
 +
 +
<pre>Copyright (C) 2010, 2011 Some Name <some@example.org>
 +
</pre>
 +
 +
Change it like this (notice the updated year):
 +
 +
<pre>Copyright (C) 2010, YEAR Some Name <some@example.org> and others.
 +
</pre>
 +
 +
If there is a section <tt>Contributors:</tt> below the legal text and your change is more than a few lines, you can add your name there and optionally describe the change and link to a bug number. You can also start such a section if you contributed a significant change.
 +
 +
When there are multiple copyright entries there, add yours as a separate line. So, given this:
 +
 +
<pre>Copyright (C) 2010 Some Name <some@example.org>
 +
Copyright (C) 2011 Other Name <other@example.org>
 +
</pre>
 +
 +
Add another line:
 +
 +
<pre>Copyright (C) 2010 Some Name <some@example.org>
 +
Copyright (C) 2011 Other Name <other@example.org>
 +
Copyright (C) YEAR Your Name <you@example.org>
 +
</pre>
 +
 +
For new files, copy one of the existing headers and start the copyright section with your name.
 +
 +
Also see http://www.eclipse.org/legal/copyrightandlicensenotice.php for more information.
  
 
== Test before submitting ==
 
== Test before submitting ==

Revision as of 06:51, 1 February 2013

EGit
Website
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Community
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Bugzilla
Open
Help Wanted
Bug Day
Contribute
Browse SourceProject Set File

Contents

Communication

Channel JGit EGit
Developer Mailing List JGit developer mailing list EGit developer mailing list
Build Notices Mailing List JGit build notices mailing list EGit build notices mailing list
Reporting Bugs File new JGit bug File new EGit bug
User Forum EGit User Forum


Obtaining Sources

EGit and JGit are self hosted in Git. Browse the repositories in cgit here EGit repositories and JGit.

There are several ways to obtain a copy of each repository:

From the command line

# for egit repositories
git clone https://git.eclipse.org/r/p/egit/egit.git
git clone https://git.eclipse.org/r/p/egit/egit-github.git
git clone https://git.eclipse.org/r/p/egit/egit-pde.git

# for jgit repository
git clone https://git.eclipse.org/r/p/jgit/jgit.git

From an installed EGit plugin

First, verify that the default repository folder as set on the main Git preference page is to your liking.

Repeat for the JGit repository: https://git.eclipse.org/r/p/jgit/jgit.git

EGit PDE Tools

EGit also provides tools for integrating with PDE Build and Eclipse RelEng Tools. If you are an Eclipse developer using PDE Build and/or the Eclipse RelEng tools you might be interesting in the following as well. Otherwise you might just skip this section.

EGit GitHub Integration

EGit also provides tools for integrating with GitHub and Mylyn tasks.

  • File > Import > Git > Projects from Git
  • URI
  • Enter URI: https://git.eclipse.org/r/p/egit/egit-github.git
  • Import projects
  • Download dependencies:
    • automagically: open file org.eclipse.mylyn.github-feature/github.target cgit and select 'Set as Target Platfrom'.
    • manually: In addition to the dependencies required for JGit and EGit you also need Eclipse PDE (>= 3.6.1) as well as org.eclipse.releng.tools in your target platform or checked out from CVS in your workspaces.


Development IDE Configuration

Tools

To install all the necessary tools to work on EGit/JGit, there is a egit-developer-tools.p2f file which you can use:

  • File > Import > Install > Install Software Items from File
  • Browse...
    • Go to the location of your egit repository, open the tools directory and select egit-developer-tools.p2f
  • All the items you don't already have should be selected automatically
  • Finish the wizard
  • Restart

Java Requirements

EGit and JGit have Java 5.0 and Eclipse Platform 3.7 as minimum requirements, so dependencies to newer Java and platform versions must be avoided.

We are using PDE/API Tools Environment Descriptions (see changes for JGit and EGit) to facilitate detecting code which isn't working on Java 5. If you followed the instructions in the Tools section above, the necessary descriptions should already be installed. Otherwise install PDE/API Tools Environment Descriptions from the release train repository, see Installing Execution Environment Descriptions.

Alternatively, add both a Java5 and a Java 6 SDK to your workspace. Do this in Window/Preferences -> Java/Installed JREs. Then configure your Execution Environments so that J2SE-1.5 refer to a Java 5 SDK and JavaSE-1.6 refer to a Java 6 installation.

If you are using OS X Snow Leopard, then Java 5 is hard to find. Using the search button in Eclipse will tell you that you have a 1.5.0 version of Java. That is probably a lie. It is just a link to 1.6. Fortunately some nice guys have made a download that you may use. Follow these instructions to download and installl a real Java 5. You do not need to make it default. Downloading, unpacking and fixing the version links is enough.

Dependencies

After importing the EGit and JGit projects in Eclipse, they will not compile due to missing dependencies. There are a few ways to install these.

Option 1: Use a Target Platform

EGit target platforms in org.eclipse.egit.target

This is the quickest and easiest method to install dependencies:

  • Open the org.eclipse.egit.target project
  • Choose one of the .target files and open it (this may take a while as it requires Internet access)
  • In the resulting editor, click on the Set as Target Platform link at the top right (this may also take a while)

After that, the workspace should build cleanly (if not, try a clean all).

There are different target definitions, one for each version of Eclipse that EGit supports. The one you select will be the one that is started if you want to try out a feature or bug fix.

You can always switch between them to test on different Eclipse versions. E.g. when you are developing some major UI functionality, you should try it with the oldest supported Eclipse release to make sure it doesn't depend on API that is only available in later versions.

Option 2: Install from Orbit P2 Repository

On the Orbit Downloads page, click on the newest stable build and copy the update site link from "Orbit Build Repository" (it should end with /repository). Add this update site in Eclipse using "Install New Software..." and then find and select the following entries:

  • Java Mocking and Stubbing Framework
  • Args4j
  • Protocol Buffers
  • Apache Jakarta log4j Plug-in
  • Apache Commons Compress
  • Hamcrest Library of Matchers

Option 3: Import Team Project Set

The simplest way to import the 3rd party libraries needed to compile JGit and Egit:

  • Download the Team Project Set for git dependencies
  • File > Import > Team > Team Project Set
  • Next
  • Select the downloaded GitDependencies.psf
  • logon with user "anonymous", leave password field blank
  • Finish

Option 4: Manual Import

Alternatively to importing the team project set, you may do a manual import of these required libraries:

Module Version
com.google.protobuf v201105131100
org.mockito v201102171835
org.objenesis v201006030720
org.kohsuke.args4j branch v2_0_12
javax.servlet branch v2_5

For each library, do the following:

  • File > Import > CVS > Projects from CVS
  • Select URL :pserver:anonymous@dev.eclipse.org:/cvsroot/tools
  • Use module org.eclipse.orbit/<module name from table>
  • Finish
  • Right click on the project > Team > Switch to another branch
  • Select tag from following list
  • Refresh Tags
  • Versions or Branches > <version/branch from table>

Running

Now that everything builds, the next step is to run an Eclipse instance with the EGit/JGit code of the workspace:

  • Right click on the org.eclipse.egit.ui project
  • Debug As > Eclipse Application

This should create a new launch configuration and start a new nested Eclipse instance in debug mode. The created launch configuration can be edited, e.g. to change where the workspace of the nested Eclipse should be located.

The launch configuration can also be used in normal (non-debug) mode of course.

Also see the reference on eclipse application launchers.


Builds

EGit and JGit builds run on build.eclipse.org via Hudson using

Hudson

JGit

  • JGit can be built using Maven 2 or 3.
  • JGit packaging projects (Eclipse feature and update site) are built using Maven 3 and Tycho.

EGit

  • EGit is built using Maven 3 and Tycho.

Mailing Lists

If you're interested in following builds, please check out the following mailing lists:

Maven Build Sequence

  • Due to a current limitation of Tycho it is not possible to mix pom-first and manifest-first builds in the same reactor build hence the pom-first JGit build has to run separately before the build for the manifest-first JGit packaging project.
  • The 3 builds must share the same local Maven repository otherwise dependencies between these builds cannot be resolved.
  • To run the build behind a firewall follow http://maven.apache.org/guides/mini/guide-proxies.html

Complete build sequence for a clean build (assuming $M2_HOME/bin is on the path and local Maven repository at ~/.m2/repository):

[~/src/jgit] $ mvn clean install
[INFO] Scanning for projects...
...

[~/src/jgit] $ mvn -f org.eclipse.jgit.packaging/pom.xml clean install
[INFO] Scanning for projects...
...

[~/src/jgit] $ cd ../egit

[~/src/egit] $ mvn clean install
[INFO] Scanning for projects...
...

The EGit build uses the JGit p2 repository to resolve jgit dependencies. For local builds the build assumes that egit and jgit source trees are located under a common parent folder. If this is not the case the path to the jgit p2 repository has to be injected via system property:

[~/src/egit] $ mvn clean install -Djgit-site=file:/path/to/
                          org.eclipse.jgit.updatesite/target/site

The hudson build on build.eclipse.org uses:

[~/src/egit] $ mvn clean install -Djgit-site=https://build.eclipse.org/hudson/job/
                          jgit/lastSuccessfulBuild/artifact/org.eclipse.jgit.packaging/
                          org.eclipse.jgit.updatesite/target/site/

If you wan to build EGit for the specific Indigo platform, consider using the platform-indigo maven profile:

[~/src/egit] $ mvn -P platform-indigo clean install

For EGit version 2.1 and earlier, 4 such platform profiles are available: platform-galileo (Eclipse 3.5), platform-helios (Eclipse 3.6), platform-indigo (Eclipse 3.7) and platform-juno (Eclipse 4.2). As of EGit 2.2, older platforms are no longer supported, therefore only platform-indigo (Eclipse 3.7) and platform-juno (Eclipse 4.2) are available.

Upon a successful build, a p2 update site should be generated inside egit/org.eclipse.egit.repository/target/repository. If not, make sure the target platform has been downloaded from within Eclipse (Windows>Preferences>Plug-in Development>Target Platform). The default target platform defined in the maven build is currently Eclipse 4.2.

FindBugs and PMD

As part of the build, JGit and EGit run FindBugs and PMD to find issues.

Checking for JGit API Changes using API Baseline

The JGit projects have API tooling enabled. In order to use PDE API tools to get assistance with maintaining API changes and additions you need to set an API baseline:

  • download the p2 repository for the latest EGit release (which includes the JGit artifacts) to a local folder, e.g. ~/egit-releases/updates-2.2, find the p2 repository URLs here and see mirroring artifacts for a way to download the repository
  • in Eclipse click "Preferences > Plug-In Development > API Baselines", click "Add Baseline..." and define a new baseline (e.g. egit-1.3) and point it to the local copy of the corresponding EGit p2 repository.
  • the API tools will then raise warning/errors for all detected problems and provide quick fixes helping to resolve these problems
  • see the PDE API Tools User Guide for more details.

Automated Signing and Publishing

EGit and JGit builds are signed and published using the eclipse-maven-signing-plugin via build.eclipse.org to the folder

/home/data/httpd/download.eclipse.org/egit/updates-nightly

To enable this procedure the maven profile build-server must be enabled via the option -P build-server in the egit build job running at https://hudson.eclipse.org/hudson/job/egit/


Signing (old method, replaced by automated procedure)

To sign the EGit build, you need to have ssh access to build.eclipse.org and the ability to run /usr/bin/sign

At the moment, Chris Aniszczyk (caniszczyk) and Matthias Sohn (msohn) have signing privileges.

The first step is to ensure you're in a place you can sign on build.eclipse.org

cd /home/data/httpd/download-staging.priv/commonBuild

Next you run the signing command (Usage: /usr/bin/sign <file> <mail|nomail> [outputDir]) on a zip of the EGit repo...

sign egit-p2-repo.zip my@email.com /home/data/users/caniszczyk/egit-0.8

After that, you can publish the zip that is generated with the signing information.

Contribution to Release Train

The Juno release train contribution for JGit and EGit is maintained in the CVS project

extssh://dev.eclipse.org/cvsroot/callisto/org.eclipse.juno.build

in the file

egit.b3aggrcon


Documentation

The EGit project sources its documentation from the wiki and generates Eclipse help content from it (under the covers, we are using Mylyn WikiText to make this possible). This significantly lowers the barrier for people to contribute documentation to the EGit project. To contribute documentation, simply modify the EGit User's Guide. Have a look at the Style Guidelines and Eclipse Documentation Style Guide to get some guidance on how to write good documentation. More on that can be found here.

The documentation is contained in the org.eclipse.egit.doc plug-in. The build-help.xml drives the generation of the help content. It is integrated into the maven build. The regular maven build of org.eclipse.egit.doc

$ mvn clean install 

will only package the help content committed to the egit repository. To update the help content by downloading the latest documentation from the wiki run

$ mvn clean install -Dupdate.egit.doc

Don't forget to check all the generated help pages and especially all hyperlinks and images before pushing the updated help to the code review system for inclusion into the continuous build.

The aim is to generate new documentation every month or so (or just on demand). If you're making big changes or want the documentation refreshed, please let us know on the egit-dev mailing list.


Tests

JGit Unit Tests

The JGit unit tests are executed during the maven build for the bundle org.eclipse.jgit.test. To run them from the Eclipse workbench use the launch configurations which are part of the sources of the bundle org.eclipse.jgit.test.

JGit HTTP Tests

The JGit HTTP tests in org.eclipse.jgit.http.test rely on the Jetty web container.

To run these tests from Eclipse the Jetty feature is needed. Use one of the target platforms as described in dependencies.

Alternatively, for Indigo (3.7.2) and JGit since 447002b3 install "Jetty 7.6.0.v20120127" from http://archive.eclipse.org/jetty/updates/jetty-bundles-7.x/7.6.0.v20120127/ . For older JGit versions install "Jetty Target Components 7.5.1.201109140245" from http://download.eclipse.org/releases/indigo.

Notes

  • currently it's not possible to install Jetty 7.6 into Juno since it already comes with Jetty 8.1 which is requiring a newer version of the servlet API which needs Java 6. Hence when using Juno you need to use the corresponding target platform in order to be able to run the JGit HTTP tests.
  • there was a problem with hanging JGit tests on some machines and with some Jetty versions. This was fixed in ac98c29d.

EGit Core Tests

The EGit Core tests are executed during the maven build for the bundle org.eclipse.egit.core.test.

To run them from the Eclipse workbench use the launch configuration which is part of the sources of the test bundle org.eclipse.egit.core.test.

EGit UI Tests

The EGit UI tests are using SWTBot, using the 'SWTBot for Eclipse Testing' feature.

You need to install at least "SWTBot for Eclipse Testing" and "SWTBot IDE Feature":

Starting a UI test from Eclipse:

  • select the test class or test method
  • click Run As > SWTBot Test

Start-swtbot-test.png

Do not touch the mouse or keyboard when the UI test is running since this may disturb the UI test by e.g. moving the current focus to another window.

During Maven Build

The tests are executed in the integration-test phase of the default Maven lifecycle.

If you want to skip execution of UI tests during the maven build run

mvn -P skip-ui-tests clean install

Note: since the SWTBot port to Eclipse 4.2 isn't yet perfect [1] a few UI tests fail on Eclipse 4.2.

[1] https://bugs.eclipse.org/bugs/show_bug.cgi?id=385527

Auxilary testing tools

Any code, including testing code, does not always do what you expected it to. The most common failure is probably the failure to actually execute the part of the code you wanted to test. Code coverage tools like EclEmma can easily visualize what part of the code is being executed.

Bugs

Links

Filing Bugs

File a bug for EGit

File a bug for JGit

Bug Reports and Links

Trends EGit JGit
Open Bugs and Enhancements Open Open
Assigned Bugs and Enhancements Assigned Assigned
Bugs with votes With Votes With Votes
All Bugs and Enhancements All All
Lists EGit JGit
Unresolved for passed Target Milestones Open Open
Open Bugs Open Open
Open Enhancements Open Open
Assigned Bugs and Enhancements Assigned Assigned
Reports EGit and JGit
Open EGit and JGit Bugs Open
Assigned EGit and JGit Bugs Assigned
New Bugs opened Last day Last week Last month Last year
Bugs closed Last day Last week Last month Last year


To get notified of bugs, go to your e-mail preferences and add <product>.<component>-inbox@eclipse.org to your watch list. For example to get notified of EGit UI bugs, add egit.ui-inbox@eclipse.org.

Keywords

To simplify bug management we started to tag EGit bugs with additional pseudo keywords (not normal Bugzilla keywords). The tags are prepended to the bug's summary field. Since we use these tags for internal bug management reporters of a bug should not add any pseudo keywords when filing the bug. The owner of the component bucket is responsible to add the keywords.

Keywords are used to group bugs without assigning them to a developer. So with the introduction of the keywords it is easy to search for all bugs belonging to a specific sub component. For example to get an overview of all open refactoring issues search for new, assigned or reopened bugs containing the word [refactoring] in the summary field.

Be aware that not all bugs are tagged with keywords, only bugs that belong to a certain sub group may have a tag attached. The following lists some of the currently used tags.

Tag Description Link
[sync] everything related to Synchronize / Synchronize View View bugs
[repoView] everything related to the Git Repository View View bugs
[releng] everything related to release engineering and build View bugs
[historyView] everything related to the Git History View View bugs


Website

The EGit and JGit websites are located in Git repositories which are configured for Gerrit code review.

egit

jgit


Contributing Patches

Review the following style guides:

Using Gerrit at https://git.eclipse.org/r

EGit and JGit projects are using Gerrit Code Review for Git based patch submission and review.

Parts of this chapter are also available in the Eclipse Gerrit wiki.

User Account

  • In order to contribute you need an Eclipse user account on eclipse.org, on creation of a new account you must agree to the Contributor Agreement.

Legal Paperwork

With every contribution, you will have to explicitly assert on the corresponding bug or as a comment on the Gerrit push record:

  1. that you are the author 100% of the content you are contributing.
  2. that you own the copyright of the contributed content (this is typically your employer.)
  3. that you have the right to contribute the content to Eclipse. (You need to confirm this with the copyright owner.)

In addition ensure

  1. that the contributed code is licensed under the project license (EPL for EGit and EDL for JGit). This is done by putting a copyright and license header into every new java file. See other existing project source files for the correct content.

With these questions answered and the copyright and license header in place, we will be able to accept small patches (<250 LoC) immediately. For larger patches, we will also have to create a contribution questionnaire for review by the Eclipse IP team, but this usually doesn't require additional actions from you.

In general, also see Handling Git Contributions via Gerrit and the committer how-to on external contributions.

bug 381105 tracks the discussion on simplifying this current legal requirement.

Logon

Gerrit Web UI

Logon to the Gerrit Web UI at https://git.eclipse.org/r/ using the email address you registered with your Eclipse (and Bugzilla) account and your Eclipse password.

Git over SSH

When accessing Gerrit over SSH from git or EGit use the username displayed here and upload your public SSH key to Gerrit here.

Gerrit SSH URl: ssh://username@git.eclipse.org:29418/egit/egit.git

Git over HTTPS

When accessing Gerrit over HTTPS from git or EGit use username and HTTP password displayed here

Gerrit HTTPS URl: https://git.eclipse.org/r/p/egit/egit.git

SSH Keys

  • Add one or more public SSH keys to Gerrit here.
  • If you are absolutely certain you do not have keys already, you must create a public and private pair of SSH keys. It is strongly recommended that you use a passphrase.
  • Generating SSH key pair on command line
ssh-keygen -t rsa -C "your_email@youremail.com"
  • Execute SSH once to accept the host key (or copy it from the registration web page)
ssh -p 29418 username@git.eclipse.org

Doing Code Reviews with Gerrit

Using Gerrit with git command line:

  • Upload your patch from Git to the target project:

JGit

git push ssh://username@git.eclipse.org:29418/jgit/jgit.git HEAD:refs/for/master

EGit

git push ssh://username@git.eclipse.org:29418/egit/egit.git HEAD:refs/for/master

Adding a dedicated remote

Since git can have multiple remotes, you can define one to be used to refer to Gerrit to save typing. Inside a previously checked-out repository you can run:

cd path/to/jgit
git config remote.review.url ssh://username@git.eclipse.org:29418/jgit/jgit.git
git config remote.review.push HEAD:refs/for/master

cd path/to/egit 
git config remote.review.url ssh://username@git.eclipse.org:29418/egit/egit.git
git config remote.review.push HEAD:refs/for/master

You can now submit review requests from either repository using:

git push review

Using Gerrit with EGit:

Eclipse will look for your private key in the SSH2 Home location specified in the General>Network Connections>SSH2 Preference Page. If your id_rsa private key makes use of the AES-128-CBC algorithm (view the file as text to confirm), Eclipse will need at least com.jcraft.jsch 0.1.44 to make use of it.

  • Clone the JGit and EGit repositories and select Gerrit Configuration... in the context menu of the remote "origin" in the Git Repositories view to configure pushing to the code review queue.
  • Alternative approach: Add a new review remote in the Git Repositories view and select Gerrit Configuration... in the context menu of the remote
    • From the appropriate Remotes node, create a New Remote and choose to Configure for Push. A unique name should be chosen, review is suggested.
    • Changes committed to your local clone can now be pushed to Gerrit using the review Remote. You will be prompted for your private key's passphrase if Eclipse is looking for it in the right place.
  • Instead of using the Gerrit Configuration... wizard you can do the configuration steps manually:

Using the Mylyn Gerrit Connector

The Mylyn Gerrit Connector can be installed from the Mylyn p2 repository, e.g. for juno from http://download.eclipse.org/mylyn/releases/juno.

It contains several useful features:

  • Cloning from Gerrit and automatic configuration
    • The wizards "Import Projects from Git" and "Clone Git Repository" will offer the possibility to browse the list of repositories on Gerrit servers and to clone selected repositories. After cloning the Gerrit configuration will be done automatically.
  • Importing Gerrit changes as Mylyn tasks
  • Fetching patch sets directly from the task editor
  • Reviewing changes in the task editor
  • Submitting changes from the task editor

Granularity of Changes

  • Make small commits, as small as reasonable. This makes them easy to review.
  • Each commit should have a commit message that explains very clearly what the commit sets out to achieve (unless this is abundantly clear from the code itself, which is basically only the case for trivial patches). Also, when you fix a bug then report which bug you fix. When there are deeper reasons for doing things the way the commit does, then explain these as well. This all is for the reviewers and yourself: the context of the commit is completely clear.
  • Do not mix concerns in commits: have a commit do a single thing. This makes them reviewable 'in isolation'. The purpose of the commit is clear and can be understood easily by the reviewers and yourself.
  • Do not break the build and tests for any commit: this is very important for bug hunting.
  • Split your work into multiple smaller pieces of work (when possible) and implement each of these pieces in a series of commits.
  • A series of commits should work towards a 'feature' in a clear way and only 'enable' the feature in the last commit of the series.
  • In a series of commits first lay the groundwork and then build on that towards the feature.
  • Do not mix concerns in branches: when you encounter a bug while working on something then create a new branch to fix the bug. If your work depends on the bug being fixed then rebase your work on that new branch.

Coding standards

Eclipse has standards for how to write code.

Coding conventions

Use interface guidelines

These documents have links to other document. Browse through them without expecting to learn everything, just so you know roughly what areas and types of details they covert. When you are not sure about how to write a piece of code or design the user interface, these are the two first places to look at.

In addition there is all the worlds collective knowledge on how to write programs that shine. When there is a conflict, the Eclipse guide lines and conventions take precedense.

Breaking the rules is ok if there is a very good reason and you can tell us what that reason is.

In addition to these general rules, we regard performance high. If the EGit plugin is slow in any way, that is a bug and should be reported and fixed. Java isn't slow, but there is a lot of slow Java code.

Braces for one-line statements

Both in JGit and EGit, the preferred coding style is to leave off braces around statements with one line, e.g.:

if (condition)
    doSomething();

Some exceptions to this rule:

  • Don't leave off braces when the inner element is a try block
  • Don't leave off braces when the inner element is a long or deeply-nested if/else block

Commit message guidelines

  • The commit message header should fit on one line and should start with an uppercase letter. A blank line separates it from the body of the message.
  • The first sentence should be a clear and concise description about the change.
  • Enter a newline before providing a more detailed description about the change.
  • Format the commit message to have newline characters after every 60-70 characters.
  • Find more reasoning about commit message formatting in "A Note About Git Commit Messages"
  • Commit message footers (everything following the last blank line in the commit message) in Key: value format are used for additional commit meta data. Some tools especially Gerrit parse this meta data to provide additional functionality.
    • If there is an associated bug number in Bugzilla about it, it should come as a Bug: footer right before Gerrit's Change-Id entry (if available) or towards the end.
    • If a Contribution Questionnaire has been issued to initiate and track the review of contributed changes by the Eclipse Foundation's IP team the IPZilla bug number should be added as CQ: footer in the format shown below
    • A Gerrit Change-Id footer is required for all changes pushed to Gerrit (to enable pushing new patchsets for the same change), it should be added in the format shown below. Use the Gerrit commit message hook or EGit to add the Change-Id.
    • A "Signed-off-by" can be added at the end of the commit message (see example below). Note: at the moment this is not required but may be used to list all who modified (amended, rebased, cherry-picked) this change.
Fix the commit dialog to respect the workbench's selection

Originally, the commit dialog would automatically check off all
files in the dialog. This behaviour contradicts a user's expectation
because their selection in the workbench is completely ignored. The
code has been corrected to only preselect what the user has actually
selected.

Bug: 12345
CQ: 6031
Change-Id: I71ac4844ab9d2f848352eba9252090c586b4146a
Signed-off-by: Your Name <your.email@example.org>

Copyright

When contributing patches, you have to update the copyright section at the beginning of the file if there is one. Please follow the style that is already present in the file. Some examples follow.

When there is only one copyright present (from a person or a company), like this:

Copyright (C) 2010, 2011 Some Name <some@example.org>

Change it like this (notice the updated year):

Copyright (C) 2010, YEAR Some Name <some@example.org> and others.

If there is a section Contributors: below the legal text and your change is more than a few lines, you can add your name there and optionally describe the change and link to a bug number. You can also start such a section if you contributed a significant change.

When there are multiple copyright entries there, add yours as a separate line. So, given this:

Copyright (C) 2010 Some Name <some@example.org>
Copyright (C) 2011 Other Name <other@example.org>

Add another line:

Copyright (C) 2010 Some Name <some@example.org>
Copyright (C) 2011 Other Name <other@example.org>
Copyright (C) YEAR Your Name <you@example.org>

For new files, copy one of the existing headers and start the copyright section with your name.

Also see http://www.eclipse.org/legal/copyrightandlicensenotice.php for more information.

Test before submitting

See the #Manual alpha testing section for some advice about how to test you work yourself.

  • Run all existing tests. It does not take very long.
  • Pay attention to the Java and Eclipse SDK baselines. EGit requires only Java5 and Eclipse 3.5. You cannot use API's that are newer. We often see breakages because Java 6 API's are used.

Note: In order to test in Eclipse 3.5 (Galileo), consider building EGit with the platform-galileo maven profile (see the #Maven Build Sequence for more details).

Sending patches by mail

Although sending patches by mail is the approved way of interacting with, and asking feedback from, the Git project, please don't send patches via git send-email. Instead, please use git format-patch to generate the mbox, and then attach that to an item in bugzilla as per the above SUBMITTING_PATCHES guides.

If you're sending a work-in-progress for a review, be aware that you can also attach work-in-progress (or RFC) items to Bugzilla; it's not just for finished patches.

However, it's generally preferred that you send items which you want comments on via Gerrit as per #Contributing_Patches, since Gerrit allows comments to be added in-line and allows the opportunity to send multiple versions of a patch after changes are made. Once a change has been submitted to Gerrit, you can then mail the developer mailing list with a request to review your change via URL or get Gerrit to send the mail on your behalf.


Gerrit Code Review Cheatsheet

Install the commit-msg hook in your repository

scp -p -P 29418 username@git.eclipse.org:hooks/commit-msg .git/hooks/

This will ask for a password. It is the password that you have to generate in the SSH Keys section of settings in your Gerrit account.

You can alternatively download the file. The hook helps append a Change-Id to your commit message.

EGit can also generate a Gerrit Change-Id into your commit message both manually or in an automated way.

To create a new change

  • JGit
git push ssh://username@git.eclipse.org:29418/jgit/jgit.git HEAD:refs/for/master
  • EGit
git push ssh://username@git.eclipse.org:29418/egit/egit.git HEAD:refs/for/master

Or, if you've followed the instructions on #Adding_a_dedicated_remote you can simply do:

git push review

Since the current repository has the right definition for 'review', you won't need to remember the canonical push URL

To update an existing change with a new commit

git push ssh://username@git.eclipse.org:29418/egit/egit.git HEAD:refs/for/master

This works because Gerrit links the new commit to the prior change based upon the Change-Id footer in the commit message. (This is automatically generated by the commit-msg hook you installed above.) If you refuse to use the commit-msg hook, or don't have a Change-Id footer, you should read the Gerrit documentation on change-id lines and replacing changes.

Note: To be picked up by Gerrit, a Change-Id line must be in the bottom portion (last paragraph) of a commit message, and may be mixed together with the Signed-off-by, Acked-by, or other such footers. So if your Change-Id line is ignored it's probably not in the last paragraph :).

To compare bulk diffs using Git

Since each Gerrit review patchset actually commits its own tree, you can pull out the trees and compare them.

If you've got a large changeset, and you want to be able to do diffs between them via (command line) git instead of browsing on the web, then you can fetch the individual changes and then perform a diff. For example, http://git.eclipse.org/r/2 shows the 'download' section for each patchset. In this case, it looks like:

Performing a git pull will both get the bits and merge them into your tree, which won't do what you want for comparison. So, in order to get the bits (but not merge), you need to do a git fetch instead. Let's say we want to diff the last two patches against each other rather than reviewing the entire patchset again:

git fetch ssh://username@git.eclipse.org/jgit refs/changes/02/2/3
git fetch ssh://username@git.eclipse.org/jgit refs/changes/02/2/4

git diff d14cc645655683ba3e30a35833fb2282142e898f 43de8d385b614c72fd796e17da75d381f6e0cc25

# or git diff d14cc6 43de8d

If you're doing this from within an already checked out project, you can do git fetch origin (or any other remote name in .git/config}.

Git fetched data will stay around in your repository, but will be 'orphaned' if no references point to it. To clean up, you can run git gc or wait until this happens automatically.

To trigger Hudson build for a change

  • Go to Trigger a Gerrit event manually page
  • Search for a change you'd like to build
  • Select the patch set(s) you want to trigger
  • Press Trigger Selected button

To approve a change

  • Click on Publish Comments
  • Vote with the radio buttons

To add a reviewer

Once you've pushed your commit to Gerrit for review, you can go to the web page (https://git.eclipse.org/r/) and see your changes. By clicking on the review, there's an option to add a reviewer by e-mail address; they'll then be sent a message indicating that they'd like your review on the item.

Code Review

The code review category indicates your opinion on the quality of the code, and how well it fits within the purpose of the existing surrounding code. A +2 vote from any committer is required before submission can occur. A -2 vote from any committer will block submission.

IP Review

The IP review category indicates whether or not the change has been properly logged under the Eclipse IP Process. Under that process, any committer should mark his/her change +1 if they were the sole author of the change. For any other change, a committer should only mark +1 after ensuring the Legal Paperwork has been done. A +1 vote is required to submit a change, while a -1 vote will block submission.

Submission Guidelines

We strive to use Gerrit to improve our understanding of the code base and improve quality.

In order to ensure a proper review happens, some simple guidelines should be followed:

  • vote 0/-1 for not-ready-to-submit (AKA WIP) own proposals, +1 otherwise;
  • If a changeset is not-ready-to-submit, please put [RFC] or [DRAFT] in the message to let people know
  • let non-trivial changes be in review for at least 24 hours
  • if you want your changeset reviewed by someone, please add them as a reviewer

Tips & Tricks

Class Loading Issues

If you encounter strange class loading issues during runtime (e.g. on UI test executions) the following might help:

Enable tracing in your launch configuration to get information how imported packages are resolved at runtime. Select the Tracing tab in your launch configuration, select "Enable tracing", select plug-in org.eclipse.osgi, select category resolver/wiring on the right side.