ExtendedPullRequestService.java

- don't set merge parameter if they are null, reported by @figaw in issue 38

PullRequestGroovyObject.java
- added an overloaded merge() to match the README.md, reported by @figaw in issue 38
- switched to Optional usage in merge()

Author: aaronjwhiteside

src/main/java/org/jenkinsci/plugins/pipeline/github/PullRequestGroovyObject.java

@@ -649,10 +649,15 @@ public void deleteComment(final long commentId) {
 
     @Whitelisted
     public String merge(final Map<String, Object> params) {
-        return merge(params.get("commitTitle") != null ? params.get("commitTitle").toString() : null,
-                     params.get("commitMessage") != null ? params.get("commitMessage").toString() : null,
-                     params.get("sha") != null ? params.get("sha").toString() : null,
-                     params.get("mergeMethod") != null ? params.get("mergeMethod").toString() : null);
+        return merge(Optional.ofNullable(params.get("commitTitle")).map(Object::toString).orElse(null),
+                     Optional.ofNullable(params.get("commitMessage")).map(Object::toString).orElse(null),
+                     Optional.ofNullable(params.get("sha")).map(Object::toString).orElse(null),
+                     Optional.ofNullable(params.get("mergeMethod")).map(Object::toString).orElse(null));
+    }
+
+    @Whitelisted
+    public String merge(final String commitMessage) {
+        return merge(null, commitMessage, null, null);
     }
 
     @Whitelisted

src/main/java/org/jenkinsci/plugins/pipeline/github/client/ExtendedPullRequestService.java

@@ -93,10 +93,18 @@ public ExtendedMergeStatus merge(final IRepositoryIdProvider repository,
         uri.append("/merge");
 
         Map<String, String> params = new HashMap<>();
-        params.put("commit_title", commitTitle);
-        params.put("commit_message", commitMessage);
-        params.put("sha", sha);
-        params.put("merge_method", mergeMethod);
+        if (commitTitle != null) {
+            params.put("commit_title", commitTitle);
+        }
+        if (commitMessage != null) {
+            params.put("commit_message", commitMessage);
+        }
+        if (sha != null) {
+            params.put("sha", sha);
+        }
+        if (mergeMethod != null) {
+            params.put("merge_method", mergeMethod);
+        }
         return getClient().put(uri.toString(), params, ExtendedMergeStatus.class);
     }