1035: Race when creating backports for bug spanning multiple repos

Reviewed-by: zsong, erikj

Author: vijayk22oracle

bots/notify/src/main/java/org/openjdk/skara/bots/notify/issue/IssueNotifier.java

@@ -31,6 +31,7 @@
 import org.openjdk.skara.jbs.*;
 import org.openjdk.skara.jcheck.JCheckConfiguration;
 import org.openjdk.skara.json.JSON;
+import org.openjdk.skara.network.UncheckedRestException;
 import org.openjdk.skara.vcs.*;
 import org.openjdk.skara.vcs.openjdk.*;
 
@@ -305,7 +306,18 @@ public void onNewCommits(HostedRepository repository, Repository localRepository
                             var existing = Backports.findIssue(issue, fixVersion);
                             if (existing.isEmpty()) {
                                 log.info("Creating new backport for " + issue.id() + " with fixVersion " + requestedVersion);
-                                issue = jbsBackport.createBackport(issue, requestedVersion, username.orElse(null), defaultSecurity(branch));
+                                try {
+                                    issue = jbsBackport.createBackport(issue, requestedVersion, username.orElse(null), defaultSecurity(branch));
+                                } catch (UncheckedRestException e) {
+                                    existing = Backports.findIssue(issue, fixVersion);
+                                    if (existing.isPresent()) {
+                                        log.info("Race condition occurred while creating backport issue, returning the existing backport for " + issue.id() + " and requested fixVersion "
+                                                + requestedVersion + " " + existing.get().id());
+                                        issue = existing.get();
+                                    } else {
+                                        throw e;
+                                    }
+                                }
                             } else {
                                 log.info("Found existing backport for " + issue.id() + " and requested fixVersion "
                                         + requestedVersion + " " + existing.get().id());