[MENFORCER-431] Introduce option to skip specific rules via custom property

maven-enforcer-plugin/src/it/projects/cli-skip-rules/invoker.properties

@@ -0,0 +1,18 @@
+# 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.
+
+invoker.goals = validate -Denforcer.skipRules=alwaysFail

maven-enforcer-plugin/src/it/projects/cli-skip-rules/pom.xml

@@ -0,0 +1,53 @@
+<?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.
+-->
+
+<project>
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>org.apache.maven.its.enforcer</groupId>
+  <artifactId>minimal-skip-rules-test</artifactId>
+  <version>0.0.1</version>
+  <packaging>jar</packaging>
+  <description>Minimal test for skipping specific rules via command line</description>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-enforcer-plugin</artifactId>
+        <version>@project.version@</version>
+        <executions>
+          <execution>
+            <id>always-pass-and-fail</id>
+            <goals>
+              <goal>enforce</goal>
+            </goals>
+            <configuration>
+              <rules>
+                <alwaysPass/>
+                <alwaysFail/>
+              </rules>
+              <fail>true</fail>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

maven-enforcer-plugin/src/it/projects/cli-skip-rules/verify.groovy

@@ -0,0 +1,20 @@
+/*
+ * 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.
+ */
+def buildLog = new File(basedir, 'build.log').text
+assert buildLog.contains('[INFO] Always pass!')

maven-enforcer-plugin/src/main/java/org/apache/maven/plugins/enforcer/EnforceMojo.java

@@ -23,7 +23,9 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import java.util.stream.Collectors;
 
+import org.apache.commons.lang3.ArrayUtils;
 import org.apache.maven.enforcer.rule.api.EnforcerLevel;
 import org.apache.maven.enforcer.rule.api.EnforcerRule;
 import org.apache.maven.enforcer.rule.api.EnforcerRule2;
@@ -131,6 +133,14 @@ public class EnforceMojo extends AbstractMojo {
     @Parameter(required = false, property = "rules")
     private String[] commandLineRules;
 
+    /**
+     * Array of Strings that matches the EnforcerRules to skip.
+     *
+     * @since 3.2.0
+     */
+    @Parameter(required = false, property = "enforcer.skipRules")
+    private String[] rulesToSkip;
+
     /**
      * Use this flag to disable rule result caching. This will cause all rules to execute on each project even if the
      * rule indicates it can safely be cached.
@@ -154,11 +164,11 @@ public void execute() throws MojoExecutionException {
         }
 
         Optional<PlexusConfiguration> rulesFromCommandLine = createRulesFromCommandLineOptions();
-
         List<EnforcerRuleDesc> rulesList;
         try {
             // current behavior - rules from command line override all other configured rules.
-            rulesList = enforcerRuleManager.createRules(rulesFromCommandLine.orElse(rules));
+            List<EnforcerRuleDesc> allRules = enforcerRuleManager.createRules(rulesFromCommandLine.orElse(rules));
+            rulesList = filterOutSkippedRules(allRules);
         } catch (EnforcerRuleManagerException e) {
             throw new MojoExecutionException(e.getMessage(), e);
         }
@@ -176,8 +186,6 @@ public void execute() throws MojoExecutionException {
         // messages with warn/error flag
         Map<String, Boolean> messages = new LinkedHashMap<>();
 
-        String currentRule = "Unknown";
-
         // create my helper
         PluginParameterExpressionEvaluator evaluator = new PluginParameterExpressionEvaluator(session, mojoExecution);
         EnforcerRuleHelper helper = new DefaultEnforcementRuleHelper(session, evaluator, log, container);
@@ -200,7 +208,7 @@ public void execute() throws MojoExecutionException {
                 EnforcerLevel level = getLevel(rule);
                 // store the current rule for
                 // logging purposes
-                currentRule = rule.getClass().getName();
+                String currentRule = rule.getClass().getName();
                 try {
                     if (ignoreCache || shouldExecute(rule)) {
                         // execute the rule
@@ -254,12 +262,10 @@ public void execute() throws MojoExecutionException {
             }
         });
 
-        // CHECKSTYLE_OFF: LineLength
         if (fail && hasErrors) {
             throw new MojoExecutionException(
                     "Some Enforcer rules have failed. Look above for specific messages explaining why the rule failed.");
         }
-        // CHECKSTYLE_ON: LineLength
     }
 
     /**
@@ -282,6 +288,22 @@ private Optional<PlexusConfiguration> createRulesFromCommandLineOptions() {
         return Optional.of(configuration);
     }
 
+    /**
+     * Filter our (remove) rules that have been specifically skipped via additional configuration.
+     *
+     * @param allRules list of enforcer rules to go through and filter
+     *
+     * @return list of filtered rules
+     */
+    private List<EnforcerRuleDesc> filterOutSkippedRules(List<EnforcerRuleDesc> allRules) {
+        if (rulesToSkip == null || rulesToSkip.length == 0) {
+            return allRules;
+        }
+        return allRules.stream()
+                .filter(ruleDesc -> !ArrayUtils.contains(rulesToSkip, ruleDesc.getName()))
+                .collect(Collectors.toList());
+    }
+
     /**
      * This method determines if a rule should execute based on the cache
      *