From 31d8fbb731153ab312ee7252ce4afc4274222149 Mon Sep 17 00:00:00 2001
From: Tim Jacomb <21194782+timja@users.noreply.github.com>
Date: Wed, 5 Aug 2026 21:50:15 +0100
Subject: [PATCH] Add more to quick-build, remove cleaning node_modules
 (#27161)
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74.4s → 45.0s (39% faster)
---
 CONTRIBUTING.md |  16 ++++++-
 core/pom.xml    |   1 +
 pom.xml         | 112 ++++++++++++++++++++++++++++++++++++++++++------
 3 files changed, 116 insertions(+), 13 deletions(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 700b2b0de4..8e3fba0624 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -35,6 +35,20 @@ mvn -am -pl war,bom -Pquick-build clean install
 ```
 
 The WAR file will be created in `war/target/jenkins.war`.
+
+> [!NOTE]
+> `quick-build` sets `maven.test.skip`, so test classes are not compiled and are not present
+> afterwards. To build something you can then run tests against, drop the profile or pass
+> `-Dmaven.test.skip=false`.
+
+`clean` deliberately leaves `node/`, `node_modules/` and `.yarn/` in place, so the node
+toolchain and the downloaded packages survive between builds. Pass `-Dclean.node` to delete
+those as well.
+
+If you are only changing backend code and `war/src/main/webapp/jsbundles` is already populated
+from an earlier build, `-Dskip.frontend=true` skips the node installation, `yarn install` and
+`yarn build`.
+
 After that, you can start Jenkins using Java CLI ([guide](https://www.jenkins.io/doc/book/installing/war-file/#run-the-war-file)).
 If you want to debug the WAR file without using Maven plugins,
 You can run the executable with [Remote Debug Flags](https://stackoverflow.com/questions/975271/remote-debugging-a-java-application)
@@ -74,7 +88,7 @@ To work on the `war` module frontend assets, two processes are needed at the sam
 On one terminal, start a development server that will not process frontend assets:
 
 ```sh
-MAVEN_OPTS='--add-opens java.base/java.lang=ALL-UNNAMED --add-opens java.base/java.io=ALL-UNNAMED --add-opens java.base/java.util=ALL-UNNAMED' mvn -pl war jetty:run -Dskip.yarn
+MAVEN_OPTS='--add-opens java.base/java.lang=ALL-UNNAMED --add-opens java.base/java.io=ALL-UNNAMED --add-opens java.base/java.util=ALL-UNNAMED' mvn -pl war jetty:run -Dskip.frontend
 ```
 
 Open another terminal and start a [webpack](https://webpack.js.org/) dev server, after [optionally adding Node and Yarn to your path](#running-the-yarn-frontend-build):
diff --git a/core/pom.xml b/core/pom.xml
index 0b4bcaa23f..922b0262cb 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -662,6 +662,7 @@ THE SOFTWARE.
             </goals>
             <phase>prepare-package</phase>
             <configuration>
+              <skip>${strip.license.comments.skip}</skip>
               <target>
                 <!-- Only the leading comment block, to leave any semantically interesting comments elsewhere in the file untouched -->
                 <replaceregexp encoding="UTF-8" match="\A(?:[ \t]*(?:[#!].*)?\r?\n)+" replace="">
diff --git a/pom.xml b/pom.xml
index f647489fde..07020e7da0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -97,6 +97,12 @@ THE SOFTWARE.
     <bridge-method-injector.version>1.32</bridge-method-injector.version>
     <spotless.check.skip>false</spotless.check.skip>
     <ban-junit4-imports.skip>false</ban-junit4-imports.skip>
+    <!-- Opt-out switches for steps that only matter when producing a release artifact.
+         Set to true by the quick-build profile below; see CONTRIBUTING.md. -->
+    <strip.license.comments.skip>false</strip.license.comments.skip>
+    <!-- Skips node installation, "yarn install" and "yarn build". Only safe when
+         war/src/main/webapp/jsbundles is already populated from an earlier build. -->
+    <skip.frontend>false</skip.frontend>
     <!-- Make sure to keep the jetty-ee9-maven-plugin version in war/pom.xml in sync with the Jetty release in Winstone: -->
     <winstone.version>8.1044.v8e30078854c2</winstone.version>
     <node.version>24.18.0</node.version>
@@ -404,6 +410,49 @@ THE SOFTWARE.
         <changelog.url>https://www.jenkins.io/changelog-stable</changelog.url>
       </properties>
     </profile>
+    <profile>
+      <!--
+        Merged by id with the quick-build profile in the parent POM, which already skips the
+        linters and static analysis. These additions turn off work that only matters when
+        producing a release artifact, so a development build spends its time compiling.
+      -->
+      <id>quick-build</id>
+      <properties>
+        <!-- Only shrinks the packaged jar. -->
+        <strip.license.comments.skip>true</strip.license.comments.skip>
+        <remoteresources.skip>true</remoteresources.skip>
+        <!--
+          The parent POM cannot set this because a plugin may be producing a test jar, but
+          nothing in this repository consumes one, so there is nothing to compile tests for.
+          Note that this means test classes are absent afterwards: drop the profile (or pass
+          -Dmaven.test.skip=false) before running tests against the build output.
+        -->
+        <maven.test.skip>true</maven.test.skip>
+      </properties>
+      <build>
+        <pluginManagement>
+          <plugins>
+            <plugin>
+              <groupId>io.jenkins.tools.maven</groupId>
+              <artifactId>license-maven-plugin</artifactId>
+              <!-- Version specified in parent POM -->
+              <executions>
+                <execution>
+                  <!--
+                    This plugin has no skip parameter, so unbind it instead. It resolves and
+                    builds the POM of every transitive dependency to produce META-INF/licenses.xml,
+                    which is only read by the "About Jenkins" page; AboutJenkins#getLicensesURL
+                    returns null when it is absent and the view already handles that.
+                  -->
+                  <id>default</id>
+                  <phase>none</phase>
+                </execution>
+              </executions>
+            </plugin>
+          </plugins>
+        </pluginManagement>
+      </build>
+    </profile>
     <profile>
       <id>yarn-execution</id>
       <activation>
@@ -427,6 +476,7 @@ THE SOFTWARE.
                 <configuration>
                   <nodeVersion>v${node.version}</nodeVersion>
                   <nodeDownloadRoot>https://repo.jenkins-ci.org/nodejs-dist/</nodeDownloadRoot>
+                  <skip>${skip.frontend}</skip>
                 </configuration>
               </execution>
               <execution>
@@ -437,6 +487,7 @@ THE SOFTWARE.
                 <phase>initialize</phase>
                 <configuration>
                   <arguments>yarn install</arguments>
+                  <skip>${skip.frontend}</skip>
                 </configuration>
               </execution>
               <execution>
@@ -447,6 +498,7 @@ THE SOFTWARE.
                 <phase>generate-sources</phase>
                 <configuration>
                   <arguments>yarn build</arguments>
+                  <skip>${skip.frontend}</skip>
                 </configuration>
               </execution>
             </executions>
@@ -456,19 +508,15 @@ THE SOFTWARE.
             <artifactId>maven-clean-plugin</artifactId>
             <!-- Version specified in grandparent POM -->
             <configuration>
+              <!--
+                The node toolchain and the downloaded packages are deliberately left alone:
+                deleting them costs several seconds of its own and then forces the node install
+                and "yarn install" to start from nothing on every build, and since .yarnrc.yml
+                sets enableGlobalCache: false, .yarn holds the only copy of the package cache.
+                "yarn install" runs at initialize on every build, so stale dependencies still
+                heal themselves. Use -Dclean.node to delete them anyway.
+              -->
               <filesets>
-                <fileset>
-                  <directory>.yarn</directory>
-                  <followSymlinks>false</followSymlinks>
-                </fileset>
-                <fileset>
-                  <directory>node</directory>
-                  <followSymlinks>false</followSymlinks>
-                </fileset>
-                <fileset>
-                  <directory>node_modules</directory>
-                  <followSymlinks>false</followSymlinks>
-                </fileset>
                 <fileset>
                   <directory>war/src/main/webapp/jsbundles</directory>
                   <followSymlinks>false</followSymlinks>
@@ -557,6 +605,46 @@ THE SOFTWARE.
         </plugins>
       </build>
     </profile>
+    <profile>
+      <!-- When changing branches that touch frontend assets this can be a good idea but not for every fresh build. -->
+      <id>clean-node</id>
+      <activation>
+        <property>
+          <name>clean.node</name>
+        </property>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-clean-plugin</artifactId>
+            <!-- Version specified in grandparent POM -->
+            <configuration>
+              <!-- Replaced rather than appended, because merging repeated <fileset> elements
+                   across profiles is not well defined. -->
+              <filesets combine.self="override">
+                <fileset>
+                  <directory>war/src/main/webapp/jsbundles</directory>
+                  <followSymlinks>false</followSymlinks>
+                </fileset>
+                <fileset>
+                  <directory>.yarn</directory>
+                  <followSymlinks>false</followSymlinks>
+                </fileset>
+                <fileset>
+                  <directory>node</directory>
+                  <followSymlinks>false</followSymlinks>
+                </fileset>
+                <fileset>
+                  <directory>node_modules</directory>
+                  <followSymlinks>false</followSymlinks>
+                </fileset>
+              </filesets>
+            </configuration>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
     <profile>
       <id>disable-symlink-tests</id>
       <activation>