Fix #367 for Maven 3.x

src/main/java/org/apache/maven/plugins/help/DescribeMojo.java

@@ -27,7 +27,6 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
-import java.util.StringTokenizer;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
@@ -37,6 +36,8 @@
 import org.apache.maven.lifecycle.Lifecycle;
 import org.apache.maven.lifecycle.internal.MojoDescriptorCreator;
 import org.apache.maven.lifecycle.mapping.LifecycleMapping;
+import org.apache.maven.lifecycle.mapping.LifecycleMojo;
+import org.apache.maven.lifecycle.mapping.LifecyclePhase;
 import org.apache.maven.model.Plugin;
 import org.apache.maven.model.building.ModelBuildingRequest;
 import org.apache.maven.plugin.MavenPluginManager;
@@ -397,7 +398,7 @@
                 name = pd.getId();
             }
         }
         append(buffer, "Name", MessageUtils.buffer().strong(name).toString(), 0);
         appendAsParagraph(buffer, "Description", toDescription(pd.getDescription()), 0);
         append(buffer, "Group Id", pd.getGroupId(), 0);
         append(buffer, "Artifact Id", pd.getArtifactId(), 0);
@@ -405,7 +406,7 @@
         append(
                 buffer,
                 "Goal Prefix",
                 MessageUtils.buffer().strong(pd.getGoalPrefix()).toString(),
                 0);
         buffer.append(LS);
 
@@ -469,7 +470,7 @@
      */
     private void describeMojoGuts(MojoDescriptor md, StringBuilder buffer, boolean fullDescription)
             throws MojoFailureException, MojoExecutionException {
         append(buffer, MessageUtils.buffer().strong(md.getFullGoalName()).toString(), 0);
 
         // indent 1
         appendAsParagraph(buffer, "Description", toDescription(md.getDescription()), 1);
@@ -482,7 +483,7 @@
         if (deprecation != null && !deprecation.isEmpty()) {
             append(
                     buffer,
                     MessageUtils.buffer().warning("Deprecated. " + deprecation).toString(),
                     1);
         }
 
@@ -612,7 +613,7 @@
                         buffer,
                         MessageUtils.buffer()
                                 .warning("Deprecated. " + deprecation)
                                 .toString(),
                         3);
             }
         }
@@ -633,14 +634,16 @@
                 throw new MojoExecutionException("The given phase '" + cmd + "' is an unknown phase.");
             }
 
-            Map<String, String> defaultLifecyclePhases = lifecycleMappings
-                    .get(project.getPackaging())
-                    .getLifecycles()
-                    .get("default")
-                    .getPhases();
             List<String> phases = lifecycle.getPhases();
 
-            if (lifecycle.getDefaultPhases() == null) {
+            if (lifecycle.getDefaultLifecyclePhases() == null
+                    || lifecycle.getDefaultLifecyclePhases().isEmpty()) {
+                Map<String, LifecyclePhase> defaultLifecyclePhases = lifecycleMappings
+                        .get(project.getPackaging())
+                        .getLifecycles()
+                        .get("default")
+                        .getLifecyclePhases();
+
                 descriptionBuffer.append("'").append(cmd);
                 descriptionBuffer
                         .append("' is a phase corresponding to this plugin:")
@@ -662,17 +665,13 @@
                 descriptionBuffer.append(LS);
                 for (String key : phases) {
                     descriptionBuffer.append("* ").append(key).append(": ");
-                    String value = defaultLifecyclePhases.get(key);
-                    if (value != null && !value.isEmpty()) {
-                        for (StringTokenizer tok = new StringTokenizer(value, ","); tok.hasMoreTokens(); ) {
-                            descriptionBuffer.append(tok.nextToken().trim());
-
-                            if (!tok.hasMoreTokens()) {
-                                descriptionBuffer.append(LS);
-                            } else {
-                                descriptionBuffer.append(", ");
-                            }
-                        }
+                    LifecyclePhase phase = defaultLifecyclePhases.get(key);
+                    if (phase != null && !phase.getMojos().isEmpty()) {
+                        descriptionBuffer
+                                .append(phase.getMojos().stream()
+                                        .map(LifecycleMojo::getGoal)
+                                        .collect(Collectors.joining(", ")))
+                                .append(LS);
                     } else {
                         descriptionBuffer.append(NOT_DEFINED).append(LS);
                     }
@@ -685,9 +684,9 @@
 
                 for (String key : phases) {
                     descriptionBuffer.append("* ").append(key).append(": ");
-                    if (lifecycle.getDefaultPhases().get(key) != null) {
+                    if (lifecycle.getDefaultLifecyclePhases().get(key) != null) {
                         descriptionBuffer
-                                .append(lifecycle.getDefaultPhases().get(key))
+                                .append(lifecycle.getDefaultLifecyclePhases().get(key))
                                 .append(LS);
                     } else {
                         descriptionBuffer.append(NOT_DEFINED).append(LS);

src/test/java/org/apache/maven/plugins/help/DescribeMojoTest.java

@@ -21,10 +21,18 @@
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
 
 import org.apache.maven.execution.MavenSession;
+import org.apache.maven.lifecycle.DefaultLifecycles;
+import org.apache.maven.lifecycle.Lifecycle;
 import org.apache.maven.lifecycle.internal.MojoDescriptorCreator;
+import org.apache.maven.lifecycle.mapping.LifecycleMapping;
+import org.apache.maven.lifecycle.mapping.LifecyclePhase;
 import org.apache.maven.model.Plugin;
 import org.apache.maven.plugin.MavenPluginManager;
 import org.apache.maven.plugin.descriptor.MojoDescriptor;
@@ -353,6 +361,97 @@ public void testLookupPluginDescriptorAMissingG() {
         }
     }
 
+    /**
+     * Regression test for Maven 3.10, where the default lifecycle has an empty map of built-in bindings. The mojo must
+     * use the packaging-specific lifecycle mapping in that case.
+     */
+    @Test
+    public void testDescribeCommandPackagingSpecificPhaseShowsBindings() throws Exception {
+        Lifecycle lifecycle = mock(Lifecycle.class);
+        when(lifecycle.getId()).thenReturn("default");
+        when(lifecycle.getPhases()).thenReturn(Arrays.asList("validate", "compile", "test", "package"));
+        when(lifecycle.getDefaultLifecyclePhases()).thenReturn(Collections.emptyMap());
+
+        Map<String, Lifecycle> phaseMap = new HashMap<>();
+        for (String phase : Arrays.asList("validate", "compile", "test", "package")) {
+            phaseMap.put(phase, lifecycle);
+        }
+        DefaultLifecycles defaultLifecycles = mock(DefaultLifecycles.class);
+        when(defaultLifecycles.getPhaseToLifecycleMap()).thenReturn(phaseMap);
+
+        Map<String, LifecyclePhase> lifecyclePhases = new LinkedHashMap<>();
+        lifecyclePhases.put(
+                "compile", new LifecyclePhase("org.apache.maven.plugins:maven-compiler-plugin:3.11.0:compile"));
+
+        org.apache.maven.lifecycle.mapping.Lifecycle mappingLifecycle =
+                mock(org.apache.maven.lifecycle.mapping.Lifecycle.class);
+        when(mappingLifecycle.getLifecyclePhases()).thenReturn(lifecyclePhases);
+        LifecycleMapping lifecycleMapping = mock(LifecycleMapping.class);
+        when(lifecycleMapping.getLifecycles()).thenReturn(Collections.singletonMap("default", mappingLifecycle));
+
+        MavenProject project = mock(MavenProject.class);
+        when(project.getPackaging()).thenReturn("jar");
+
+        DescribeMojo mojo = new DescribeMojo();
+        setFieldWithReflection(mojo, "cmd", "compile");
+        setFieldWithReflection(mojo, "defaultLifecycles", defaultLifecycles);
+        setFieldWithReflection(mojo, "lifecycleMappings", Collections.singletonMap("jar", lifecycleMapping));
+        setParentFieldWithReflection(mojo, "project", project);
+
+        StringBuilder buffer = new StringBuilder();
+        Method describeCommand = DescribeMojo.class.getDeclaredMethod("describeCommand", StringBuilder.class);
+        describeCommand.setAccessible(true);
+        boolean result = (boolean) describeCommand.invoke(mojo, buffer);
+
+        String output = buffer.toString();
+        assertFalse(result);
+        assertTrue("Should show the compiler plugin: " + output, output.contains("maven-compiler-plugin"));
+        assertFalse("compile should not be 'Not defined': " + output, output.contains("* compile: Not defined"));
+        assertTrue("validate has no binding: " + output, output.contains("* validate: Not defined"));
+        assertTrue(output, output.contains("It is a part of the lifecycle for the POM packaging 'jar'"));
+    }
+
+    @Test
+    public void testDescribeCommandBuiltinLifecyclePhaseShowsBindings() throws Exception {
+        Map<String, LifecyclePhase> lifecyclePhases = new LinkedHashMap<>();
+        lifecyclePhases.put("pre-clean", null);
+        lifecyclePhases.put("clean", new LifecyclePhase("org.apache.maven.plugins:maven-clean-plugin:3.2.0:clean"));
+        lifecyclePhases.put("post-clean", null);
+
+        Lifecycle lifecycle = mock(Lifecycle.class);
+        when(lifecycle.getId()).thenReturn("clean");
+        when(lifecycle.getPhases()).thenReturn(Arrays.asList("pre-clean", "clean", "post-clean"));
+        when(lifecycle.getDefaultLifecyclePhases()).thenReturn(lifecyclePhases);
+
+        Map<String, Lifecycle> phaseMap = new HashMap<>();
+        for (String phase : Arrays.asList("pre-clean", "clean", "post-clean")) {
+            phaseMap.put(phase, lifecycle);
+        }
+        DefaultLifecycles defaultLifecycles = mock(DefaultLifecycles.class);
+        when(defaultLifecycles.getPhaseToLifecycleMap()).thenReturn(phaseMap);
+
+        MavenProject project = mock(MavenProject.class);
+        when(project.getPackaging()).thenReturn("jar");
+
+        DescribeMojo mojo = new DescribeMojo();
+        setFieldWithReflection(mojo, "cmd", "clean");
+        setFieldWithReflection(mojo, "defaultLifecycles", defaultLifecycles);
+        setFieldWithReflection(mojo, "lifecycleMappings", Collections.emptyMap());
+        setParentFieldWithReflection(mojo, "project", project);
+
+        StringBuilder buffer = new StringBuilder();
+        Method describeCommand = DescribeMojo.class.getDeclaredMethod("describeCommand", StringBuilder.class);
+        describeCommand.setAccessible(true);
+        boolean result = (boolean) describeCommand.invoke(mojo, buffer);
+
+        String output = buffer.toString();
+        assertFalse(result);
+        assertTrue(output, output.contains("'clean' is a phase within the 'clean' lifecycle"));
+        assertTrue(output, output.contains("maven-clean-plugin"));
+        assertTrue(output, output.contains("* pre-clean: Not defined"));
+        assertTrue(output, output.contains("* post-clean: Not defined"));
+    }
+
     private static void setParentFieldWithReflection(
             final DescribeMojo mojo, final String fieldName, final Object value)
             throws NoSuchFieldException, IllegalAccessException {