Add subscriber for check run event in order to handle rerun request

src/main/java/io/jenkins/plugins/checks/github/CheckRunGHEventSubscriber.java

@@ -97,6 +97,12 @@ private void scheduleRerun(final GHEventPayload.CheckRun checkRun, final String
             if (source.isPresent() && source.get().getRepoOwner().equals(repository.getOwnerName())
                     && source.get().getRepository().equals(repository.getName())
                     && job.getName().equals(branchName)) {
+                if (!gitHubSCMFacade.findHeadCommit(source.get(), job.getLastBuild())
+                        .equals(checkRun.getCheckRun().getHeadSha())) {
+                    LOGGER.log(Level.INFO, "Ignored the rerun request since it's not requested for the head commit.");
+                    return;
+                }
+
                 Cause cause = new GitHubChecksRerunActionCause(checkRun.getSender().getLogin());
                 ParameterizedJobMixIn.scheduleBuild2(job, 0, new CauseAction(cause));
 

src/main/java/io/jenkins/plugins/checks/github/GitHubSCMFacade.java

@@ -3,12 +3,16 @@
 import com.cloudbees.plugins.credentials.CredentialsMatchers;
 import com.cloudbees.plugins.credentials.CredentialsProvider;
 import hudson.model.Job;
+import hudson.model.Run;
 import hudson.security.ACL;
+import jenkins.plugins.git.AbstractGitSCMSource;
 import jenkins.scm.api.SCMHead;
 import jenkins.scm.api.SCMRevision;
+import jenkins.scm.api.SCMRevisionAction;
 import jenkins.scm.api.SCMSource;
 import org.jenkinsci.plugins.github_branch_source.GitHubAppCredentials;
 import org.jenkinsci.plugins.github_branch_source.GitHubSCMSource;
+import org.jenkinsci.plugins.github_branch_source.PullRequestSCMRevision;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -78,4 +82,24 @@ public Optional<SCMRevision> findRevision(final GitHubSCMSource source, final SC
                     source.getRepoOwner() + "/" + source.getRepository(), head.getName()), e);
         }
     }
+
+    /**
+     * Find the commit from given {@code build}.
+     *
+     * @param source
+     *         the scm source the {@code build} is using
+     * @param build
+     *         the target build
+     * @return the found commit
+     */
+    public String findHeadCommit(final GitHubSCMSource source, final Run<?, ?> build) {
+        SCMRevision revision = SCMRevisionAction.getRevision(source, build);
+        if (revision instanceof AbstractGitSCMSource.SCMRevisionImpl) {
+            return ((AbstractGitSCMSource.SCMRevisionImpl)revision).getHash();
+        } else if (revision instanceof PullRequestSCMRevision) {
+            return ((PullRequestSCMRevision) revision).getPullHash();
+        } else {
+            throw new IllegalArgumentException("Unsupported revision " + revision);
+        }
+    }
 }

src/test/java/io/jenkins/plugins/checks/github/CheckRunGHEventSubscriberTest.java

@@ -1,7 +1,6 @@
 package io.jenkins.plugins.checks.github;
 
-import hudson.model.Item;
-import hudson.model.Job;
+import hudson.model.*;
 import io.jenkins.plugins.util.JenkinsFacade;
 import org.apache.commons.io.FileUtils;
 import org.jenkinsci.plugins.github.extension.GHSubscriberEvent;
@@ -122,6 +121,34 @@ void shouldNotScheduleRerunWhenNoProperJobFound() throws IOException {
                         + "branch: PR-1");
     }
 
+    @Test
+    void shouldNotScheduleRerunWhenWhenRerunIsNotRequestedForHeadCommit() throws IOException {
+        Job job = mock(Job.class);
+        Run lastBuild = mock(Run.class);
+        JenkinsFacade jenkinsFacade = mock(JenkinsFacade.class);
+        GitHubSCMFacade scmFacade = mock(GitHubSCMFacade.class);
+        GitHubSCMSource source = mock(GitHubSCMSource.class);
+
+        when(jenkinsFacade.getAllJobs()).thenReturn(Collections.singletonList(job));
+        when(jenkinsFacade.getFullNameOf(job)).thenReturn("Sandbox/PR-1");
+        when(scmFacade.findGitHubSCMSource(job)).thenReturn(Optional.of(source));
+        when(source.getRepoOwner()).thenReturn("XiongKezhi");
+        when(source.getRepository()).thenReturn("Sandbox");
+        when(job.getNextBuildNumber()).thenReturn(1);
+        when(job.getName()).thenReturn("PR-1");
+        when(job.getLastBuild()).thenReturn(lastBuild);
+        when(scmFacade.findHeadCommit(source, lastBuild)).thenReturn("a1b2c3");
+
+        loggerRule.record(CheckRunGHEventSubscriber.class.getName(), Level.INFO).capture(1);
+        new CheckRunGHEventSubscriber(jenkinsFacade, scmFacade)
+                .onEvent(new GHSubscriberEvent("shouldNotScheduleRerunWhenWhenRerunIsNotRequestedForHeadCommit",
+                        GHEvent.CHECK_RUN, FileUtils.readFileToString(new File(getClass().getResource(
+                                getClass().getSimpleName() + "/check-run-event-with-rerun-action.json").getFile()),
+                                StandardCharsets.UTF_8)));
+        assertThat(loggerRule.getMessages())
+                .contains("Ignored the rerun request since it's not requested for the head commit.");
+    }
+
     @Test
     void shouldContainsUserInShortDescriptionOfGitHubChecksRerunActionCause() {
         CheckRunGHEventSubscriber.GitHubChecksRerunActionCause cause =