build.xml

<project name="jenkins-bugs-master-branch" default="sync" basedir=".">

  <property environment="env"/>

  <target name="is-first-build">
    <condition property="first.build">
      <equals arg1="${env.BUILD_NUMBER}" arg2="1"/>
    </condition>
  </target>

  <!-- Check environment variables only in builds 2+ -->
  <target name="check-non-initial-build" description="Check git env vars at build 2+" depends="is-first-build" if="env.JENKINS_URL" unless="first.build">
    <fail message="GIT_PREVIOUS_COMMIT not set" unless="env.GIT_PREVIOUS_COMMIT"/>
    <fail message="GIT_PREVIOUS_SUCCESSFUL_COMMIT not set" unless="env.GIT_PREVIOUS_SUCCESSFUL_COMMIT"/>
  </target>

  <!-- Check environment variables in all builds -->
  <target name="check-git-env-vars" description="Check all git env vars" depends="check-non-initial-build" if="env.JENKINS_URL">
    <fail message="GIT_AUTHOR_EMAIL not set" unless="env.GIT_AUTHOR_EMAIL"/>
    <fail message="GIT_AUTHOR_NAME not set" unless="env.GIT_AUTHOR_NAME"/>
    <fail message="GIT_BRANCH not set" unless="env.GIT_BRANCH"/>
    <fail message="GIT_COMMIT not set" unless="env.GIT_COMMIT"/>
    <fail message="GIT_COMMITTER_EMAIL not set" unless="env.GIT_COMMITTER_EMAIL"/>
    <fail message="GIT_COMMITTER_NAME not set" unless="env.GIT_COMMITTER_NAME"/>
    <fail message="GIT_LOCAL_BRANCH not set" unless="env.GIT_LOCAL_BRANCH"/>
    <fail message="GIT_URL not set" unless="env.GIT_URL"/>
    <echo>GIT_ env var checks all passed</echo>
  </target>

  <!-- Synchronize repositories -->
  <target name="sync" description="Synchronize git repositories">
    <git command="pull">
      <args>
        <arg value="--all"/>
        <arg value="--prune"/>
      </args>
    </git>
  </target>

  <target name="increment" description="Increment build number">
    <buildnumber/>
    <git command="commit">
      <args>
        <arg value="-m"/>
        <arg value="[${ant.project.name}] ${user.name} build++, was ${build.number}"/>
        <arg value="build.number"/>
      </args>
    </git>
  </target>

  <!-- Info about this repository -->
  <target name="info" description="Report info about this repo">
    <echo>java is ${java.version}</echo>
    <echo>user dir is ${user.dir}</echo>
    <git command="branch" />
    <!-- JENKINS-41906 reports that master branch built without
         any commits.  This reports commits on this branch in the last 15
         minutes -->
    <echo>Displaying git log messages on this branch from last 15 minutes</echo>
    <git command="log">
      <args>
        <arg value="--since='15 minutes ago'"/>
      </args>
    </git>
    <echo>End of git log messages on this branch from last 15 minutes</echo>
  </target>

  <!-- From https://gist.github.com/davejlong/874521 -->
  <macrodef name="git">
    <attribute name="command" />
    <attribute name="dir" default="" />
    <element name="args" optional="true" />
    <sequential>
      <echo message="git @{command}" />
      <exec executable="git" dir="@{dir}">
        <arg value="@{command}" />
        <args/>
      </exec>
    </sequential>
  </macrodef>

</project>