CI: fix approval job to compare against project upstream master

The job was comparing against "origin/master", which for MR submitted
from forks is likely not the target project.  This updates the API
script that fetches the MR info to also output the target project URL,
from which an 'upstream' remote is fetched for comparison.

.gitlab-ci.yml

@@ -64,28 +64,28 @@ noise_change_approval:
   script:
     - export PYTHONPATH=/inspiral_range
     - |
-      cat <<EOF > check_approved.py
-      import sys
+      cat <<EOF > merge_info_env.py
       import gitlab
-      project_id = sys.argv[1]
-      mr_iid = sys.argv[2]
+      project_id = $CI_MERGE_REQUEST_PROJECT_ID
+      mr_iid = $CI_MERGE_REQUEST_IID
       # this only works for public repos, otherwise need to specify
       # private_token=
       gl = gitlab.Gitlab('https://git.ligo.org')
       project = gl.projects.get(project_id)
       mr = project.mergerequests.get(mr_iid)
       approvals = mr.approvals.get()
-      print(approvals.approved)
+      print('TARGET_URL={}'.format(project.http_url_to_repo))
+      print('MR_APPROVED={}'.format(approvals.approved))
       EOF
-    - echo CI_MERGE_REQUEST_PROJECT_ID=$CI_MERGE_REQUEST_PROJECT_ID
-    - echo CI_MERGE_REQUEST_IID=$CI_MERGE_REQUEST_IID
-    - echo CI_MERGE_REQUEST_TARGET_BRANCH_NAME=$CI_MERGE_REQUEST_TARGET_BRANCH_NAME
-    - approved=$(python3 check_approved.py $CI_MERGE_REQUEST_PROJECT_ID $CI_MERGE_REQUEST_IID )
-    - if [[ $approved != True ]] ; then
+    - python3 merge_info_env.py > ENV
+    - . ENV
+    - if [[ $MR_APPROVED != True ]] ; then
     -     echo "Approval not yet given, checking for noise changes..."
-    -     target=origin/$CI_MERGE_REQUEST_TARGET_BRANCH_NAME
-    -     if ! python3 -m gwinc.test --git-rev $target -r gwinc_test_report.pdf ; then
-    -         echo "NOISE CHANGES RELATIVE TO $CI_MERGE_REQUEST_TARGET_BRANCH_NAME."
+    -     git remote add upstream $TARGET_URL
+    -     git remote update
+    -     TARGET_REV=upstream/$CI_MERGE_REQUEST_TARGET_BRANCH_NAME
+    -     if ! python3 -m gwinc.test --git-rev $TARGET_REV -r gwinc_test_report.pdf ; then
+    -         echo "NOISE CHANGES RELATIVE TO $TARGET_REV"
     -         echo "Approval required to merge this branch."
     -         /bin/false
     -     else