api: Include merge reference into API data of a PR.

rhodecode/api/views/pull_request_api.py

@@ -96,8 +96,14 b' def get_pull_request(request, apiuser, r'
                                          "commit_id": "<commit_id>",
                                      }
                                  },
-            "shadow":            {
+            "merge":             {
                                      "clone_url":   "<clone_url>",
+                                     "reference":
+                                     {
+                                         "name":      "<name>",
+                                         "type":      "<type>",
+                                         "commit_id": "<commit_id>",
+                                     }
                                  },
            "author":             <user_obj>,
            "reviewers":          [
@@ -181,8 +187,14 b' def get_pull_requests(request, apiuser, '
                                              "commit_id": "<commit_id>",
                                          }
                                      },
-                "shadow":            {
+                "merge":             {
                                          "clone_url":   "<clone_url>",
+                                         "reference":
+                                         {
+                                             "name":      "<name>",
+                                             "type":      "<type>",
+                                             "commit_id": "<commit_id>",
+                                         }
                                      },
                "author":             <user_obj>,
                "reviewers":          [

rhodecode/model/db.py

@@ -3137,9 +3137,18 b' class PullRequest(Base, _PullRequestBase'
         from rhodecode.model.pull_request import PullRequestModel
         pull_request = self
         merge_status = PullRequestModel().merge_status(pull_request)
+
         pull_request_url = url(
             'pullrequest_show', repo_name=self.target_repo.repo_name,
             pull_request_id=self.pull_request_id, qualified=True)
+
+        merge_data = {
+            'clone_url': PullRequestModel().get_shadow_clone_url(pull_request),
+            'reference': (
+                pull_request.shadow_merge_ref._asdict()
+                if pull_request.shadow_merge_ref else None),
+        }
+
         data = {
             'pull_request_id': pull_request.pull_request_id,
             'url': pull_request_url,
@@ -3172,10 +3181,7 b' class PullRequest(Base, _PullRequestBase'
                     'commit_id': pull_request.target_ref_parts.commit_id,
                 },
             },
-            'shadow': {
-                'clone_url': PullRequestModel().get_shadow_clone_url(
-                    pull_request),
-            },
+            'merge': merge_data,
             'author': pull_request.author.get_api_data(include_secrets=False,
                                                        details='basic'),
             'reviewers': [