CI: merge_gitlab_ci: Improve error handling.

merge_gitlab_ci.py

@@ -139,9 +139,20 @@ def main():
         if branch is None:
             branch = project.default_branch
 
+        print(
+            "Try to merge {}({}) into {} ({})".format(
+                args.submodule, args.revision, project.name, branch
+            )
+        )
+
         mr = find_integration_merge_request(
             project, args.submodule, args.revision, branch
         )
+        if mr is None:
+            sys.exit("ERROR: Failed to find the integration MR.")
+            # TODO if this ever happens, why ever, we could call
+            # deploy_gitlab_ci again to create a new integration
+            # commit or make sure the change is already integrated.
 
         print("Merge {}!{}: {}".format(project.name, mr.iid, mr.title))
         # Wait until GitLab has checked merge status
@@ -157,13 +168,24 @@ def main():
         )
 
         if not merged:
-            sys.exit(
-                "Integration MR could not be merged. You have two possibilities to fix "
-                "this:\n"
-                "  1. Checkout the MR and rebase it on the current master manually, or\n"
-                "  2. Delete the MR (Edit -> Delete in the MR UI)\n"
-                "In either case restart this job afterwards in order to get it merged."
+            print(
+                "Integration MR could not be merged."
+                "To fix this:\n"
+                "  1. Checkout the MR {}!{} and merge it manually.\n"
+                "  2. Manually merge the follow up MRs in the following project:".format(
+                    project.name, mr.iid
+                )
             )
+            found = False
+            for p2 in args.projects + [args.project]:
+                if p2 == p:
+                    found = True
+                    continue
+                if not found:
+                    continue
+                print("     {}".format(p2.name))
+            sys.exit()
+
     print("Successfully merged")
 
     exit()