Sync - handle existing PR

CHANGELOG.md

@@ -8,7 +8,6 @@ Apologies for the inconvenience.
 * Fix syntax error in `/push_dockerhub.yml` GitHub Action workflow
 * Change `params.readPaths` -> `params.input_paths` in `test_full.config`
 * Check results when posting the lint results as a GitHub comment
-* Change `params.readPaths` -> `params.input_paths` in `test_full.config`
 
 ## [v1.10.1 - Copper Camel _(patch)_](https://github.com/nf-core/tools/releases/tag/1.10.1) - [2020-07-30]
 

nf_core/sync.py

@@ -317,13 +317,20 @@ def make_pull_request(self):
             self.gh_pr_returned_data = r.content
             returned_data_prettyprint = r.content
 
-        if r.status_code != 201:
+        # PR worked
+        if r.status_code == 201:
+            log.debug("GitHub API PR worked:\n{}".format(returned_data_prettyprint))
+            log.info("GitHub PR created: {}".format(self.gh_pr_returned_data["html_url"]))
+
+        # We already had a PR open
+        elif r.status_code == 422:
+            log.warn("GitHub PR is already open!")
+
+        # Something went wrong
+        else:
             raise PullRequestException(
                 "GitHub API returned code {}: \n{}".format(r.status_code, returned_data_prettyprint)
             )
-        else:
-            log.debug("GitHub API PR worked:\n{}".format(returned_data_prettyprint))
-            log.info("GitHub PR created: {}".format(self.gh_pr_returned_data["html_url"]))
 
     def reset_target_dir(self):
         """