From 89530f1a1cb2e90b5368605fc317eaed35bf9d1f Mon Sep 17 00:00:00 2001
From: Tom Krizek <tkrizek@isc.org>
Date: Thu, 15 Dec 2022 17:51:24 +0100
Subject: [PATCH] danger: check that original MR has been merged

When checking a backport MR, ensure that the original MR has been merged
already. This is vital for followup checks that verify commit IDs from
original commits are present in backport commit messages.
---
 dangerfile.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/dangerfile.py b/dangerfile.py
index 7f0797232c..de7a6cef0c 100644
--- a/dangerfile.py
+++ b/dangerfile.py
@@ -175,6 +175,8 @@ if not danger.gitlab.mr.milestone:
 # * The Backport MR doesn't have target branch in the merge request title.
 #
 # * The Backport MR doesn't link to the original MR is its description.
+#
+# * The original MR linked to from Backport MR hasn't been merged.
 
 BACKPORT_OF_RE = re.compile(
     r"Backport\s+of.*(merge_requests/|!)([0-9]+)", flags=re.IGNORECASE
@@ -199,6 +201,14 @@ if is_backport:
             "Backport MRs must link to the original MR. Please put "
             "`Backport of MR !XXXX` in the MR description."
         )
+    else:  # backport MR is linked to original MR
+        original_mr_id = backport_desc.groups()[1]
+        original_mr = proj.mergerequests.get(original_mr_id)
+        if original_mr.state != "merged":
+            fail(
+                f"Original MR !{original_mr_id} has not been merged. "
+                "Please re-run `danger` check once it's merged."
+            )
 if not is_backport and not version_labels:
     fail(
         "If this merge request is a backport, set the *Backport* label and "