[JENKINS-39520] ExtensionList.removeAll is unimplemented (#2612)

* Work around SUREFIRE-1226 just like https://github.com/jenkinsci/plugin-pom/pull/33.

* [JENKINS-39520] Implement ExtensionList.removeAll.

* @oleg-nenashev suggests not notifying listeners unless we are actually removing something.

core/src/main/java/hudson/ExtensionList.java

@@ -204,6 +204,21 @@ public class ExtensionList<T> extends AbstractList<T> implements OnMaster {
         }
     }
 
+    @Override
+    public boolean removeAll(Collection<?> c) {
+        boolean removed = false;
+        try {
+            for (Object o : c) {
+                removed |= removeSync(o);
+            }
+            return removed;
+        } finally {
+            if (extensions != null && removed) {
+                fireOnChangeListeners();
+            }
+        }
+    }
+
     private synchronized boolean removeSync(Object o) {
         boolean removed = removeComponent(legacyInstances, o);
         if(extensions!=null) {

test/pom.xml

@@ -40,6 +40,7 @@ THE SOFTWARE.
     <concurrency>2</concurrency> <!-- may use e.g. 2C for 2 × (number of cores) -->
     <mavenDebug>false</mavenDebug>
     <jacocoSurefireArgs /><!-- empty by default -->
+    <trimStackTrace>false</trimStackTrace> <!-- SUREFIRE-1226 workaround -->
   </properties>
 
   <dependencies>

test/src/test/java/hudson/ExtensionListTest.java

@@ -10,12 +10,14 @@ import jenkins.model.Jenkins;
 import hudson.model.Descriptor;
 import hudson.model.Describable;
 import hudson.util.DescriptorList;
+import java.util.ArrayList;
 
 import java.util.List;
 import java.util.Collection;
 
 import org.junit.Rule;
 import org.junit.Test;
+import org.jvnet.hudson.test.Issue;
 import org.jvnet.hudson.test.JenkinsRule;
 import org.jvnet.hudson.test.WithoutJenkins;
 
@@ -204,4 +206,15 @@ public class ExtensionListTest {
         assertEquals("mazda",list.get(1).name);
         assertEquals("toyota",list.get(2).name);
     }
+
+    @Issue("JENKINS-39520")
+    @Test
+    public void removeAll() {
+        ExtensionList<Animal> list = ExtensionList.lookup(Animal.class);
+        assertTrue(list.removeAll(new ArrayList<>(list)));
+        assertEquals(0, list.size());
+        assertFalse(list.removeAll(new ArrayList<>(list)));
+        assertEquals(0, list.size());
+    }
+
 }