ci: check whether Deckard submodule commit is present on master

This is to prevent issues like knot/knot-resolver!1036

.gitlab-ci.yml

@@ -168,6 +168,12 @@ build:darwin:
   script:
     - ci/travis.py ${CI_COMMIT_REF_NAME}
 
+deckard_commit:
+  <<: *test_nodep
+  script:
+    - ci/deckard_commit_check.sh
+  allow_failure: true
+  
 deckard:
   <<: *test_flaky
   tags:

ci/deckard_commit_check.sh

+DECKARD_COMMIT=$(git ls-tree HEAD:tests/integration/ | grep commit | grep deckard | cut -f1 | cut -f3 '-d ')
+DECKARD_PATH="tests/integration/deckard"
+pushd $DECKARD_PATH > /dev/null
+if git merge-base --is-ancestor $DECKARD_COMMIT origin/master; then
+	echo "Deckard submodule commit is on in its master branch. All good in the hood."
+	exit 0
+else
+	echo "Deckard submodule commit $DECKARD_COMMIT is not in Deckard's master branch."
+	echo "This WILL cause CI breakages so make sure your changes in Deckard are merged"
+	echo "or point the submodule to another commit."
+	exit 1
+fi
+