[MBUILDCACHE-48] - Add possibility to disable caching per module in a multi-module project

src/main/java/org/apache/maven/buildcache/BuildCacheMojosExecutionStrategy.java

@@ -99,12 +99,17 @@ public void execute(
         CacheState cacheState = DISABLED;
         CacheResult result = CacheResult.empty();
         boolean skipCache = cacheConfig.isSkipCache() || MavenProjectInput.isSkipCache(project);
+        boolean cacheIsDisabled = MavenProjectInput.isCacheDisabled(project);
         if (source == Source.LIFECYCLE) {
             List<MojoExecution> cleanPhase = lifecyclePhasesHelper.getCleanSegment(project, mojoExecutions);
             for (MojoExecution mojoExecution : cleanPhase) {
                 mojoExecutionRunner.run(mojoExecution);
             }
-            cacheState = cacheConfig.initialize();
+            if (!cacheIsDisabled) {
+                cacheState = cacheConfig.initialize();
+            } else {
+                LOGGER.info("Cache is explicitly disabled on project level for {}", getVersionlessProjectKey(project));
+            }
             if (cacheState == INITIALIZED || skipCache) {
                 result = cacheController.findCachedBuild(session, project, mojoExecutions, skipCache);
             }

src/main/java/org/apache/maven/buildcache/CacheControllerImpl.java

@@ -455,9 +455,17 @@ public void save(
                     localCache.saveArtifactFile(cacheResult, projectArtifact);
                 }
                 for (org.apache.maven.artifact.Artifact attachedArtifact : attachedArtifacts) {
-                    if (attachedArtifact.getFile() != null
-                            && isOutputArtifact(attachedArtifact.getFile().getName())) {
-                        localCache.saveArtifactFile(cacheResult, attachedArtifact);
+                    if (attachedArtifact.getFile() != null) {
+                        boolean storeArtifact =
+                                isOutputArtifact(attachedArtifact.getFile().getName());
+                        if (storeArtifact) {
+                            localCache.saveArtifactFile(cacheResult, attachedArtifact);
+                        } else {
+                            LOGGER.debug(
+                                    "Skipping attached project artifact '{}' = "
+                                            + " it is marked for exclusion from caching",
+                                    attachedArtifact.getFile().getName());
+                        }
                     }
                 }
             } else {

src/main/java/org/apache/maven/buildcache/checksum/MavenProjectInput.java

@@ -90,6 +90,7 @@
 import static org.apache.commons.lang3.StringUtils.stripToEmpty;
 import static org.apache.maven.buildcache.CacheUtils.isPom;
 import static org.apache.maven.buildcache.CacheUtils.isSnapshot;
+import static org.apache.maven.buildcache.xml.CacheConfigImpl.CACHE_ENABLED_PROPERTY_NAME;
 import static org.apache.maven.buildcache.xml.CacheConfigImpl.CACHE_SKIP;
 import static org.apache.maven.buildcache.xml.CacheConfigImpl.RESTORE_GENERATED_SOURCES_PROPERTY_NAME;
 
@@ -733,6 +734,12 @@ public int compare(Path f1, Path f2) {
         }
     }
 
+    /**
+     * Skip lookup on a per-project level via a property to force module rebuild
+     * e.g.{@code <maven.build.cache.skipCache>true<maven.build.cache.skipCache/>}
+     * @param project
+     * @return
+     */
     public static boolean isSkipCache(MavenProject project) {
         return Boolean.parseBoolean(project.getProperties().getProperty(CACHE_SKIP, "false"));
     }
@@ -748,4 +755,15 @@ public static boolean isRestoreGeneratedSources(MavenProject project) {
         return Boolean.parseBoolean(
                 project.getProperties().getProperty(RESTORE_GENERATED_SOURCES_PROPERTY_NAME, "true"));
     }
+
+    /**
+     * Allow disabling caching entirely on a per-project level via a property - both artifact lookup and upload
+     * Defaults to false
+     * {@code <maven.build.cache.enabled>false<maven.build.cache.enabled/>}
+     * @param project
+     * @return
+     */
+    public static boolean isCacheDisabled(MavenProject project) {
+        return !Boolean.parseBoolean(project.getProperties().getProperty(CACHE_ENABLED_PROPERTY_NAME, "true"));
+    }
 }

src/test/java/org/apache/maven/buildcache/its/PerModuleFlagsTest.java

@@ -0,0 +1,52 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.maven.buildcache.its;
+
+import java.io.IOException;
+
+import org.apache.maven.buildcache.its.junit.IntegrationTest;
+import org.apache.maven.it.VerificationException;
+import org.apache.maven.it.Verifier;
+import org.junit.jupiter.api.Test;
+
+@IntegrationTest("src/test/projects/per-module-flags")
+public class PerModuleFlagsTest {
+    private static final String PROJECT_NAME_MODULE1 = "org.apache.maven.caching.test.multimodule:module1";
+    private static final String PROJECT_NAME_MODULE2 = "org.apache.maven.caching.test.multimodule:module2";
+    private static final String PROJECT_NAME_MODULE3 = "org.apache.maven.caching.test.multimodule:module3";
+
+    @Test
+    void simple(Verifier verifier) throws VerificationException, IOException {
+        verifier.setAutoclean(false);
+
+        // 1st build
+        verifier.setLogFileName("../log-1.txt");
+        verifier.executeGoal("verify");
+        verifier.verifyErrorFreeLog();
+
+        // 2nd build
+        verifier.setLogFileName("../log-2.txt");
+        verifier.executeGoal("verify");
+        verifier.verifyErrorFreeLog();
+        verifier.verifyTextInLog("Found cached build, restoring " + PROJECT_NAME_MODULE1 + " from cache");
+        verifier.verifyTextInLog("Project " + PROJECT_NAME_MODULE2
+                + " is marked as requiring force rebuild, will skip lookup in build cache");
+        verifier.verifyTextInLog("Cache is explicitly disabled on project level for " + PROJECT_NAME_MODULE3);
+    }
+}

src/test/projects/per-module-flags/.mvn/extensions.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    Copyright 2021 the original author or authors.
+
+    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.
+
+-->
+<extensions>
+    <extension>
+        <groupId>org.apache.maven.extensions</groupId>
+        <artifactId>maven-build-cache-extension</artifactId>
+        <version>${projectVersion}</version>
+    </extension>
+</extensions>

src/test/projects/per-module-flags/.mvn/maven-build-cache-config.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+
+<!--
+Licensed to the Apache Software Foundation (ASF) under one
+or more contributor license agreements.  See the NOTICE file
+distributed with this work for additional information
+regarding copyright ownership.  The ASF licenses this file
+to you 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.
+-->
+
+<cache xmlns="http://maven.apache.org/CACHE-CONFIG/1.0.0">
+
+</cache>

src/test/projects/per-module-flags/module1/pom.xml

@@ -0,0 +1,33 @@
+<!--
+
+    Copyright 2021 the original author or authors.
+
+    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.
+
+-->
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>module1</artifactId>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>org.apache.maven.caching.test.multimodule</groupId>
+        <artifactId>top</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../pom.xml</relativePath>
+    </parent>
+
+    <!-- this subproject should be cached -->
+</project>

src/test/projects/per-module-flags/module1/src/main/java/org/apache/maven/buildcache/Test1.java

@@ -0,0 +1,24 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.maven.buildcache;
+
+class Test
+{
+
+}

src/test/projects/per-module-flags/module2/pom.xml

@@ -0,0 +1,38 @@
+<!--
+
+    Copyright 2021 the original author or authors.
+
+    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.
+
+-->
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>module2</artifactId>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>org.apache.maven.caching.test.multimodule</groupId>
+        <artifactId>top</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../pom.xml</relativePath>
+    </parent>
+
+    <!-- this subproject demonstrates usage of maven.build.cache.skipCache flag -
+      forced rebuild with no lookup-->
+    <properties>
+        <maven.build.cache.skipCache>true</maven.build.cache.skipCache>
+    </properties>
+
+</project>

src/test/projects/per-module-flags/module2/src/main/java/org/apache/maven/buildcache/Test2.java

@@ -0,0 +1,24 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.maven.buildcache;
+
+class Test
+{
+
+}

src/test/projects/per-module-flags/module3/pom.xml

@@ -0,0 +1,38 @@
+<!--
+
+    Copyright 2021 the original author or authors.
+
+    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.
+
+-->
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>module3</artifactId>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>org.apache.maven.caching.test.multimodule</groupId>
+        <artifactId>top</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../pom.xml</relativePath>
+    </parent>
+
+    <!-- this subproject demonstrates usage of maven.build.cache.enabled flag -
+       disabled caching on per-module level-->
+    <properties>
+        <maven.build.cache.enabled>false</maven.build.cache.enabled>
+    </properties>
+
+</project>

src/test/projects/per-module-flags/module3/src/main/java/org/apache/maven/buildcache/Test3.java

@@ -0,0 +1,24 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.maven.buildcache;
+
+class Test
+{
+
+}