diff --git a/rhodecode/model/pull_request.py b/rhodecode/model/pull_request.py
index b4734db2..890182c6 100644
--- a/rhodecode/model/pull_request.py
+++ b/rhodecode/model/pull_request.py
@@ -2405,6 +2405,17 @@ class MergeCheck(object):
                 return merge_check
 
         log.debug("MergeCheck: is failed: %s", merge_check.failed)
+
+        if merge_check.failed:
+            close_branch = PullRequestModel()._close_branch_before_merging(pull_request)
+            if close_branch:
+                close_msg = cls._get_branch_close_or_delete_message(_, pull_request)
+                merge_check.error_details["extra_info"] = {
+                    "details": "detailed_info",
+                    "message": close_msg,
+                    "error_type": "extra_info",
+                }
+
         return merge_check
 
     @classmethod
@@ -2422,17 +2433,29 @@ class MergeCheck(object):
 
         close_branch = model._close_branch_before_merging(pull_request)
         if close_branch:
-            repo_type = pull_request.target_repo.repo_type
-            close_msg = ""
-            if repo_type == "hg":
-                close_msg = _("Source branch will be closed before the merge.")
-            elif repo_type == "git":
-                close_msg = _("Source branch will be deleted after the merge.")
-
+            close_msg = cls._get_branch_close_or_delete_message(_, pull_request)
             merge_details["close_branch"] = dict(details={}, message=close_msg)
 
         return merge_details
 
+    @classmethod
+    def _get_branch_close_or_delete_message(cls, translator, pull_request):
+        _ = translator
+
+        repo_type = pull_request.target_repo.repo_type
+        close_msg = ""
+        branch_name = pull_request.source_ref_parts.name
+        max_branch_length = 20
+        shorten_branch_name = (
+            f"{branch_name[:max_branch_length]}..." if len(branch_name) > max_branch_length else branch_name
+        )
+        message_template = "Source branch '%s' will be {action} before the merge." % shorten_branch_name
+        if repo_type == "hg":
+            close_msg = _(message_template.format(action="closed"))
+        elif repo_type == "git":
+            close_msg = _(message_template.format(action="deleted"))
+        return close_msg
+
 
 @dataclasses.dataclass
 class ChangeTuple: