Fix canceling outdated Maven projects

The original code would only look for instances of Build to be canceled.
MavenBuild inherits from AbstractBuild but not from Build, so Maven
builds would not be canceled.

Use Run for elements of the job.getBuilds(), it is type safe and provides
the necessary API.

Use run.getId() in the log for better readability.

Check the result of getExecutor(), it has @checkfornull attribute.

Author: proski

src/main/java/stashpullrequestbuilder/stashpullrequestbuilder/StashBuildTrigger.java

@@ -10,9 +10,9 @@
 import com.cloudbees.plugins.credentials.domains.URIRequirementBuilder;
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import hudson.Extension;
-import hudson.model.Build;
 import hudson.model.Cause;
 import hudson.model.CauseAction;
+import hudson.model.Executor;
 import hudson.model.Item;
 import hudson.model.Job;
 import hudson.model.ParameterDefinition;
@@ -21,6 +21,7 @@
 import hudson.model.ParametersDefinitionProperty;
 import hudson.model.Queue;
 import hudson.model.Result;
+import hudson.model.Run;
 import hudson.model.StringParameterValue;
 import hudson.model.queue.QueueTaskFuture;
 import hudson.model.queue.Tasks;
@@ -258,12 +259,12 @@ private void cancelPreviousJobsInQueueThatMatch(@Nonnull StashCause stashCause)
 
   private void abortRunningJobsThatMatch(@Nonnull StashCause stashCause) {
     logger.fine("Looking for running jobs that match PR ID: " + stashCause.getPullRequestId());
-    for (Object o : job.getBuilds()) {
-      if (o instanceof Build) {
-        Build build = (Build) o;
-        if (build.isBuilding() && hasCauseFromTheSamePullRequest(build.getCauses(), stashCause)) {
-          logger.info("Aborting build: " + build + " since PR is outdated");
-          build.getExecutor().interrupt(Result.ABORTED);
+    for (Run<?, ?> run : job.getBuilds()) {
+      if (run.isBuilding() && hasCauseFromTheSamePullRequest(run.getCauses(), stashCause)) {
+        logger.info("Aborting build: " + run.getId() + " since PR is outdated");
+        Executor executor = run.getExecutor();
+        if (executor != null) {
+          executor.interrupt(Result.ABORTED);
         }
       }
     }