diff --git a/bots/pr/src/main/java/org/openjdk/skara/bots/pr/CheckRun.java b/bots/pr/src/main/java/org/openjdk/skara/bots/pr/CheckRun.java
index 7a15c1364..0709073cd 100644
--- a/bots/pr/src/main/java/org/openjdk/skara/bots/pr/CheckRun.java
+++ b/bots/pr/src/main/java/org/openjdk/skara/bots/pr/CheckRun.java
@@ -654,7 +654,7 @@ private void addSourceBranchWarningComment(List<Comment> comments) throws IOExce
             "a branch with the same name as the source branch for this pull request (`" + branch + "`) " +
             "is present in the [target repository](" + pr.repository().nonTransformedWebUrl() + "). " +
             "If you eventually integrate this pull request then the branch `" + branch + "` " +
-            "in your [personal fork](" + pr.sourceRepository().nonTransformedWebUrl() + ") will diverge once you sync " +
+            "in your [personal fork](" + pr.sourceRepository().get().nonTransformedWebUrl() + ") will diverge once you sync " +
             "your personal fork with the upstream repository.\n" +
             "\n" +
             "To avoid this situation, create a new branch for your changes and reset the `" + branch + "` branch. " +
@@ -782,9 +782,11 @@ private void checkStatus() {
                 newLabels.remove("merge-conflict");
             }
 
-            var branchNames = pr.repository().branches().stream().map(HostedBranch::name).collect(Collectors.toSet());
-            if (!pr.repository().url().equals(pr.sourceRepository().url()) && branchNames.contains(pr.sourceRef())) {
-                addSourceBranchWarningComment(comments);
+            if (pr.sourceRepository().isPresent()) {
+                var branchNames = pr.repository().branches().stream().map(HostedBranch::name).collect(Collectors.toSet());
+                if (!pr.repository().url().equals(pr.sourceRepository().get().url()) && branchNames.contains(pr.sourceRef())) {
+                    addSourceBranchWarningComment(comments);
+                }
             }
 
             if (!PullRequestUtils.isMerge(pr) && PullRequestUtils.containsForeignMerge(pr, localRepo)) {
diff --git a/bots/tester/src/test/java/org/openjdk/skara/bots/tester/InMemoryPullRequest.java b/bots/tester/src/test/java/org/openjdk/skara/bots/tester/InMemoryPullRequest.java
index a4ca46e7d..8a4111a19 100644
--- a/bots/tester/src/test/java/org/openjdk/skara/bots/tester/InMemoryPullRequest.java
+++ b/bots/tester/src/test/java/org/openjdk/skara/bots/tester/InMemoryPullRequest.java
@@ -96,8 +96,8 @@ public String sourceRef() {
     }
 
     @Override
-    public HostedRepository sourceRepository() {
-        return null;
+    public Optional<HostedRepository> sourceRepository() {
+        return Optional.empty();
     }
 
     @Override
diff --git a/cli/src/main/java/org/openjdk/skara/cli/pr/GitPrList.java b/cli/src/main/java/org/openjdk/skara/cli/pr/GitPrList.java
index 555d74b3f..3eaba87b7 100644
--- a/cli/src/main/java/org/openjdk/skara/cli/pr/GitPrList.java
+++ b/cli/src/main/java/org/openjdk/skara/cli/pr/GitPrList.java
@@ -208,7 +208,7 @@ public static void main(String[] args) throws IOException {
             issues.add(String.join(",", prIssues));
             urls.add(pr.webUrl().toString());
 
-            if (pr.sourceRepository().webUrl().equals(uri)) {
+            if (pr.sourceRepository().isPresent() && pr.sourceRepository().get().webUrl().equals(uri)) {
                 branches.add(pr.sourceRef());
             } else {
                 branches.add("");
diff --git a/forge/src/main/java/org/openjdk/skara/forge/PullRequest.java b/forge/src/main/java/org/openjdk/skara/forge/PullRequest.java
index 0faa6c2df..2820f82a0 100644
--- a/forge/src/main/java/org/openjdk/skara/forge/PullRequest.java
+++ b/forge/src/main/java/org/openjdk/skara/forge/PullRequest.java
@@ -88,7 +88,7 @@ public interface PullRequest extends Issue {
      * Returns the repository the request is created from.
      * @return
      */
-    HostedRepository sourceRepository();
+    Optional<HostedRepository> sourceRepository();
 
     /**
      * Returns the name of the ref the request is intended to be merged into.
diff --git a/forge/src/main/java/org/openjdk/skara/forge/github/GitHubPullRequest.java b/forge/src/main/java/org/openjdk/skara/forge/github/GitHubPullRequest.java
index e12865b27..882484547 100644
--- a/forge/src/main/java/org/openjdk/skara/forge/github/GitHubPullRequest.java
+++ b/forge/src/main/java/org/openjdk/skara/forge/github/GitHubPullRequest.java
@@ -247,8 +247,12 @@ public String sourceRef() {
     }
 
     @Override
-    public HostedRepository sourceRepository() {
-        return new GitHubRepository(host, json.get("head").get("repo").get("full_name").asString());
+    public Optional<HostedRepository> sourceRepository() {
+        if (json.get("head").get("repo").isNull()) {
+            return Optional.empty();
+        } else {
+            return Optional.of(new GitHubRepository(host, json.get("head").get("repo").get("full_name").asString()));
+        }
     }
 
     @Override
diff --git a/forge/src/main/java/org/openjdk/skara/forge/gitlab/GitLabMergeRequest.java b/forge/src/main/java/org/openjdk/skara/forge/gitlab/GitLabMergeRequest.java
index f780ad920..de77aaf20 100644
--- a/forge/src/main/java/org/openjdk/skara/forge/gitlab/GitLabMergeRequest.java
+++ b/forge/src/main/java/org/openjdk/skara/forge/gitlab/GitLabMergeRequest.java
@@ -267,9 +267,13 @@ public String sourceRef() {
     }
 
     @Override
-    public HostedRepository sourceRepository() {
-        return new GitLabRepository((GitLabHost) repository.forge(),
-                                    json.get("source_project_id").asInt());
+    public Optional<HostedRepository> sourceRepository() {
+        if (json.get("source_project_id").isNull()) {
+            return Optional.empty();
+        } else {
+            return Optional.of(new GitLabRepository((GitLabHost) repository.forge(),
+                                                    json.get("source_project_id").asInt()));
+        }
     }
 
     @Override
diff --git a/test/src/main/java/org/openjdk/skara/test/TestPullRequest.java b/test/src/main/java/org/openjdk/skara/test/TestPullRequest.java
index 66b9ac29e..352b2d8b9 100644
--- a/test/src/main/java/org/openjdk/skara/test/TestPullRequest.java
+++ b/test/src/main/java/org/openjdk/skara/test/TestPullRequest.java
@@ -146,8 +146,8 @@ public String sourceRef() {
     }
 
     @Override
-    public HostedRepository sourceRepository() {
-        return sourceRepository;
+    public Optional<HostedRepository> sourceRepository() {
+        return Optional.of(sourceRepository);
     }
 
     @Override