feat: allow skipping Vaadin maven plugin execution during a build

flow-plugins/flow-maven-plugin/src/it/vaadin-skip-test/invoker.properties

@@ -0,0 +1,18 @@
+#
+# Copyright 2000-2025 Vaadin Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+#
+
+invoker.goals=clean flow:prepare-frontend
+invoker.buildResult=success

flow-plugins/flow-maven-plugin/src/it/vaadin-skip-test/pom.xml

@@ -0,0 +1,54 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.vaadin.test.maven</groupId>
+    <artifactId>vaadin-skip-test</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+
+    <description>
+        Tests the vaadin.skip parameter functionality.
+    </description>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.release>21</maven.compiler.release>
+        <maven.compiler.source>${maven.compiler.release}</maven.compiler.source>
+        <maven.compiler.target>${maven.compiler.release}</maven.compiler.target>
+        <maven.test.skip>true</maven.test.skip>
+        <flow.version>@project.version@</flow.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.vaadin</groupId>
+            <artifactId>flow-server</artifactId>
+            <version>${flow.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.vaadin</groupId>
+            <artifactId>flow-client</artifactId>
+            <version>${flow.version}</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.13.0</version>
+            </plugin>
+            <plugin>
+                <groupId>com.vaadin</groupId>
+                <artifactId>flow-maven-plugin</artifactId>
+                <version>${flow.version}</version>
+                <configuration>
+                    <skip>true</skip>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>

flow-plugins/flow-maven-plugin/src/it/vaadin-skip-test/src/main/java/com/vaadin/test/SkipTestView.java

@@ -0,0 +1,9 @@
+package com.vaadin.test;
+
+import com.vaadin.flow.component.Component;
+import com.vaadin.flow.router.Route;
+
+@Route
+public class SkipTestView extends Component { 
+
+}

flow-plugins/flow-maven-plugin/src/it/vaadin-skip-test/verify.bsh

@@ -0,0 +1,13 @@
+import java.nio.file.*;
+
+flowTsx = basedir.toPath().resolve("build.log");
+if ( !Files.exists(flowTsx, new LinkOption[0]) )
+{
+    throw new RuntimeException("build.log not found");
+}
+
+lines = Files.readString(flowTsx);
+if ( !lines.contains("Skipping Vaadin build") ) 
+{
+    throw new RuntimeException("Vaadin build not skipped");
+}

flow-plugins/flow-maven-plugin/src/main/java/com/vaadin/flow/plugin/maven/FlowModeAbstractMojo.java

@@ -313,6 +313,12 @@ public abstract class FlowModeAbstractMojo extends AbstractMojo
             + InitParameters.COMMERCIAL_WITH_BANNER, defaultValue = "false")
     private boolean commercialWithBanner;
 
+    /**
+     * Skip the execution of this plugin.
+     */
+    @Parameter(property = "vaadin.skip", defaultValue = "false")
+    private boolean skip;
+
     static final String CLASSFINDER_FIELD_NAME = "classFinder";
     private ClassFinder classFinder;
 
@@ -325,6 +331,11 @@ void setBuildContext(BuildContext buildContext) {
 
     @Override
     public void execute() throws MojoExecutionException, MojoFailureException {
+        if (skip) {
+            getLog().info("Skipping Vaadin build");
+            return;
+        }
+
         PluginDescriptor pluginDescriptor = mojoExecution.getMojoDescriptor()
                 .getPluginDescriptor();
         checkFlowCompatibility(pluginDescriptor);

flow-plugins/flow-maven-plugin/src/test/java/com/vaadin/flow/plugin/maven/SkipExecutionTest.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2000-2025 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.flow.plugin.maven;
+
+import java.io.File;
+
+import org.apache.maven.plugin.logging.Log;
+import org.codehaus.plexus.util.ReflectionUtils;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.mockito.Mockito;
+
+import static com.vaadin.flow.plugin.maven.BuildFrontendMojoTest.setProject;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+
+public class SkipExecutionTest {
+
+    @Rule
+    public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+    private PrepareFrontendMojo mojo;
+    private Log mockLog;
+    private File projectBase;
+
+    @Before
+    public void setup() throws Exception {
+        mojo = new PrepareFrontendMojo();
+        mockLog = Mockito.mock(Log.class);
+        projectBase = temporaryFolder.getRoot();
+
+        // Set up the mojo with basic configuration
+        ReflectionUtils.setVariableValueInObject(mojo, "projectBasedir",
+                projectBase);
+        ReflectionUtils.setVariableValueInObject(mojo, "frontendDirectory",
+                new File(projectBase, "src/main/frontend"));
+
+        setProject(mojo, projectBase);
+
+        // Use reflection to set the mock logger
+        ReflectionUtils.setVariableValueInObject(mojo, "log", mockLog);
+    }
+
+    @Test
+    public void testSkipExecutionWhenVaadinSkipIsTrue() throws Exception {
+        // Set the skip parameter to true
+        ReflectionUtils.setVariableValueInObject(mojo, "skip", true);
+
+        // Execute the mojo
+        mojo.execute();
+
+        // Verify that the skip message was logged
+        verify(mockLog).info("Skipping Vaadin build");
+    }
+
+    @Test
+    public void testNormalExecutionWhenVaadinSkipIsFalse() throws Exception {
+        // Set the skip parameter to false (default)
+        ReflectionUtils.setVariableValueInObject(mojo, "skip", false);
+
+        try {
+            // Execute the mojo - this might fail due to missing dependencies in
+            // test env
+            mojo.execute();
+        } catch (Exception e) {
+            // Expected - we're just testing that skip message is not logged
+        }
+
+        // Verify that the skip message was NOT logged
+        verify(mockLog, never()).info("Skipping Vaadin build");
+    }
+}