From 8ebfcb6b5aaf0d6f699b734e80a77599cbbb07bf 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.

(cherry picked from commit 89530f1a1cb2e90b5368605fc317eaed35bf9d1f)
---
 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 "