Enable publishing of incremental builds

.mvn/extensions.xml

@@ -0,0 +1,7 @@
+<extensions xmlns="http://maven.apache.org/EXTENSIONS/1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/EXTENSIONS/1.0.0 http://maven.apache.org/xsd/core-extensions-1.0.0.xsd">
+  <extension>
+    <groupId>io.jenkins.tools.incrementals</groupId>
+    <artifactId>git-changelist-maven-extension</artifactId>
+    <version>1.4</version>
+  </extension>
+</extensions>

.mvn/maven.config

@@ -0,0 +1,2 @@
+-Pconsume-incrementals
+-Pmight-produce-incrementals-with-minimal-flattening

Jenkinsfile

@@ -1,12 +1,24 @@
-properties([buildDiscarder(logRotator(numToKeepStr: '20'))])
+properties([
+  buildDiscarder(logRotator(numToKeepStr: '10')),
+  disableConcurrentBuilds(abortPrevious: true)
+])
+
 node('maven-11') {
-    checkout scm
+  stage('Checkout') {
+    infra.checkoutSCM()
+  }
+
+  stage('Build') {
     timeout(time: 1, unit: 'HOURS') {
-        // TODO Azure mirror
-        ansiColor('xterm') {
-            withEnv(['MAVEN_OPTS=-Djansi.force=true']) {
-                sh 'mvn -B -Dstyle.color=always -ntp clean verify'
-            }
-        }
+      def mavenOptions = [
+        '-Dset.changelist',
+        'clean',
+        'install',
+      ]
+      infra.runMaven(mavenOptions, 11)
+      infra.prepareToPublishIncrementals()
     }
+  }
 }
+
+infra.maybePublishIncrementals()

pom.xml

@@ -27,18 +27,18 @@
 
   <groupId>org.jenkins-ci.plugins</groupId>
   <artifactId>plugin</artifactId>
-  <version>4.50-SNAPSHOT</version>
+  <version>${revision}${changelist}</version>
   <packaging>pom</packaging>
 
   <name>Jenkins Plugin Parent POM</name>
   <description>The Jenkins Plugins Parent POM Project</description>
   <inceptionYear>2016</inceptionYear>
 
   <scm>
-    <connection>scm:git:https://github.com/jenkinsci/plugin-pom.git</connection>
-    <developerConnection>scm:git:[email protected]:jenkinsci/plugin-pom.git</developerConnection>
-    <tag>HEAD</tag>
-    <url>https://github.com/jenkinsci/plugin-pom</url>
+    <connection>scm:git:https://github.com/${gitHubRepo}.git</connection>
+    <developerConnection>scm:git:[email protected]:${gitHubRepo}.git</developerConnection>
+    <tag>${scmTag}</tag>
+    <url>https://github.com/${gitHubRepo}</url>
   </scm>
 
   <distributionManagement>
@@ -54,6 +54,9 @@
   </distributionManagement>
 
   <properties>
+    <revision>4.50</revision>
+    <changelist>-SNAPSHOT</changelist>
+    <gitHubRepo>jenkinsci/plugin-pom</gitHubRepo>
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
     <project.build.outputEncoding>UTF-8</project.build.outputEncoding>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
@@ -1471,6 +1474,100 @@
         </plugins>
       </build>
     </profile>
+    <!--
+      A profile that is identical to "might-produce-incrementals" but with "flatten-maven-plugin"
+      configured to interpolate variables in the "scm", "url", and "version" elements and keep all
+      other elements untouched. This is only intended to be used with repositories like "pom" and
+      "plugin-pom". If the POM from these repositories were flattened with the "oss" flatten mode,
+      then the resulting incremental build would be missing critical sections and would not be
+      suitable for consumers. If the "scm", "url", and "version" elements were not interpolated,
+      then the resulting incremental build would contain e.g. an SCM tag of "${scmTag}" and could
+      not be published to the incrementals repository.
+    -->
+    <profile>
+      <id>might-produce-incrementals-with-minimal-flattening</id>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.codehaus.mojo</groupId>
+            <artifactId>flatten-maven-plugin</artifactId>
+            <version>1.3.0</version>
+            <configuration>
+              <updatePomFile>true</updatePomFile>
+            </configuration>
+            <executions>
+              <execution>
+                <id>flatten</id>
+                <goals>
+                  <goal>flatten</goal>
+                </goals>
+                <phase>process-resources</phase>
+                <configuration>
+                  <keepCommentsInPom>true</keepCommentsInPom>
+                  <pomElements>
+                    <build>keep</build>
+                    <ciManagement>keep</ciManagement>
+                    <contributors>keep</contributors>
+                    <dependencies>keep</dependencies>
+                    <dependencyManagement>keep</dependencyManagement>
+                    <description>keep</description>
+                    <developers>keep</developers>
+                    <distributionManagement>keep</distributionManagement>
+                    <inceptionYear>keep</inceptionYear>
+                    <issueManagement>keep</issueManagement>
+                    <mailingLists>keep</mailingLists>
+                    <modules>keep</modules>
+                    <name>keep</name>
+                    <organization>keep</organization>
+                    <parent>keep</parent>
+                    <pluginManagement>keep</pluginManagement>
+                    <pluginRepositories>keep</pluginRepositories>
+                    <prerequisites>keep</prerequisites>
+                    <profiles>keep</profiles>
+                    <properties>keep</properties>
+                    <reporting>keep</reporting>
+                    <repositories>keep</repositories>
+                    <scm>interpolate</scm>
+                    <url>interpolate</url>
+                    <version>interpolate</version>
+                  </pomElements>
+                  <outputDirectory>${project.build.directory}</outputDirectory>
+                  <flattenedPomFilename>${project.artifactId}-${project.version}.pom</flattenedPomFilename>
+                </configuration>
+              </execution>
+            </executions>
+          </plugin>
+          <plugin>
+            <artifactId>maven-enforcer-plugin</artifactId>
+            <dependencies>
+              <dependency>
+                <groupId>io.jenkins.tools.incrementals</groupId>
+                <artifactId>incrementals-enforcer-rules</artifactId>
+                <version>1.4</version>
+              </dependency>
+            </dependencies>
+            <executions>
+              <execution>
+                <id>display-info</id>
+                <configuration>
+                  <rules>
+                    <rule implementation="io.jenkins.tools.incrementals.enforcer.RequireExtensionVersion">
+                      <version>[1.0-beta-4,)</version>
+                    </rule>
+                  </rules>
+                </configuration>
+              </execution>
+            </executions>
+          </plugin>
+          <plugin>
+            <artifactId>maven-release-plugin</artifactId>
+            <configuration>
+              <completionGoals>incrementals:reincrementalify</completionGoals>
+            </configuration>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
     <profile>
       <id>produce-incrementals</id>
       <activation>