1948: User not getting push access to backport branch

Reviewed-by: zsong

Author: erikj79

bots/pr/src/main/java/org/openjdk/skara/bots/pr/BackportCommand.java

@@ -322,8 +322,15 @@ public void handle(PullRequestBot bot, HostedCommit commit, LimitedCensusInstanc
 
             if (!fork.canPush(realUser)) {
                 fork.addCollaborator(realUser, true);
+            } else {
+                // It's not possible to add branch level push protection unless the user
+                // already has push permissions in the repository. If we try to restrict
+                // it anyway, nobody can push to the branch. At least this way, if the
+                // user already has push permissions, the branch will be protected,
+                // otherwise anyone with push permissions in the repository will be able
+                // to push to the branch.
+                fork.restrictPushAccess(new Branch(backportBranchName), realUser);
             }
-            fork.restrictPushAccess(new Branch(backportBranchName), realUser);
 
             var message = CommitMessageParsers.v1.parse(commit);
             var formatter = DateTimeFormatter.ofPattern("d MMM uuuu");

forge/src/test/java/org/openjdk/skara/forge/github/GitHubRestApiTests.java

@@ -268,4 +268,12 @@ void testDeleteDeployKey() {
         var githubRepo = githubRepoOpt.get();
         githubRepo.deleteDeployKeys(Duration.ofHours(24));
     }
+
+    @Test
+    void restrictPushAccess() {
+        var gitHubRepo = githubHost.repository(settings.getProperty("github.repository")).orElseThrow();
+        var branch = new Branch(settings.getProperty("github.repository.branch"));
+        var user = githubHost.user(settings.getProperty("github.user2")).orElseThrow();
+        gitHubRepo.restrictPushAccess(branch, user);
+    }
 }