[FIXED JENKINS-22395] Attempt to double-delete a Run probably caused by...

[FIXED JENKINS-22395] Attempt to double-delete a Run probably caused by getNextBuild sometimes returning a build which was already deleted.

core/src/main/java/jenkins/model/lazy/LazyBuildMixIn.java

@@ -324,17 +324,13 @@ public abstract class LazyBuildMixIn<JobT extends Job<JobT,RunT> & Queue.Task &
          * To implement {@link Run#dropLinks}.
          */
         public final void dropLinks() {
-            if (nextBuildR != null) {
-                RunT nb = nextBuildR.get();
-                if (nb != null) {
-                    nb.getRunMixIn().previousBuildR = previousBuildR;
-                }
+            RunT nb = getNextBuild();
+            if (nb != null) {
+                nb.getRunMixIn().previousBuildR = previousBuildR;
             }
-            if (previousBuildR != null) {
-                RunT pb = previousBuildR.get();
-                if (pb != null) {
-                    pb.getRunMixIn().nextBuildR = nextBuildR;
-                }
+            RunT pb = getPreviousBuild();
+            if (pb != null) {
+                pb.getRunMixIn().nextBuildR = nextBuildR;
             }
         }
 

test/src/test/java/jenkins/model/lazy/LazyBuildMixInTest.java

+/*
+ * The MIT License
+ *
+ * Copyright 2014 Jesse Glick.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package jenkins.model.lazy;
+
+import hudson.model.FreeStyleBuild;
+import hudson.model.FreeStyleProject;
+import java.lang.ref.SoftReference;
+import java.util.ArrayList;
+import java.util.List;
+import static org.junit.Assert.*;
+import org.junit.Rule;
+import org.junit.Test;
+import org.jvnet.hudson.test.Bug;
+import org.jvnet.hudson.test.JenkinsRule;
+import org.jvnet.hudson.test.TestExtension;
+
+public class LazyBuildMixInTest {
+
+    @Rule public JenkinsRule r = new JenkinsRule();
+
+    @Bug(22395)
+    @Test public void dropLinksAfterGC() throws Exception {
+        FreeStyleProject p = r.createFreeStyleProject();
+        FreeStyleBuild b1 = r.buildAndAssertSuccess(p);
+        FreeStyleBuild b2 = r.buildAndAssertSuccess(p);
+        FreeStyleBuild b3 = r.buildAndAssertSuccess(p);
+        assertEquals(b2, b1.getNextBuild());
+        assertEquals(b3, b2.getNextBuild());
+        assertEquals(null, b3.getNextBuild());
+        assertEquals(null, b1.getPreviousBuild());
+        assertEquals(b1, b2.getPreviousBuild());
+        assertEquals(b2, b3.getPreviousBuild());
+        assertEquals(1, BRHF.drop(b1));
+        b2.delete();
+        FreeStyleBuild b1a = b2.getPreviousBuild();
+        assertNotSame(b1, b1a);
+        assertEquals(1, b1a.getNumber());
+        assertEquals(b3, b1a.getNextBuild());
+    }
+    /**
+     * Unlike the standard {@link SoftReference} this lets us simulate a referent disappearing at a specific time.
+     */
+    @TestExtension("dropLinksAfterGC") public static final class BRHF implements BuildReference.HolderFactory {
+        private static final List<BRH<?>> refs = new ArrayList<BRH<?>>();
+        private static final class BRH<R> implements BuildReference.Holder<R> {
+            R r;
+            BRH(R r) {this.r = r;}
+            @Override public R get() {return r;}
+        }
+        @Override public <R> BuildReference.Holder<R> make(R referent) {
+            BRH<R> ref = new BRH<R>(referent);
+            synchronized (refs) {
+                refs.add(ref);
+            }
+            return ref;
+        }
+        /**
+         * Simulates garbage collection of a referent.
+         * @return how many build references went null as a result
+         */
+        static int drop(Object o) {
+            int count = 0;
+            synchronized (refs) {
+                for (BRH<?> ref : refs) {
+                    if (ref.r == o) {
+                        ref.r = null;
+                        count++;
+                    }
+                }
+            }
+            return count;
+        }
+    }
+
+}