Factor out Complement checking-out

.ci/scripts/setup_complement_prerequisites.sh

@@ -29,3 +29,8 @@ block Install custom gotestfmt template
   cp synapse/.ci/complement_package.gotpl .gotestfmt/github/package.gotpl
 endblock
 
+block Check out Complement
+  # Attempt to check out the same branch of Complement as the PR. If it
+  # doesn't exist, fallback to HEAD.
+  synapse/.ci/scripts/checkout_complement.sh
+endblock

.github/workflows/tests.yml

@@ -340,11 +340,6 @@ jobs:
       - name: Prepare Complement's Prerequisites
         run: synapse/.ci/scripts/setup_complement_prerequisites.sh
 
-      # Attempt to check out the same branch of Complement as the PR. If it
-      # doesn't exist, fallback to HEAD.
-      - name: Checkout complement
-        run: synapse/.ci/scripts/checkout_complement.sh
-
       - run: |
           set -o pipefail
           POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt

.github/workflows/twisted_trunk.yml

@@ -135,11 +135,6 @@ jobs:
           # NOT IN 1.1.12 poetry lock --check
         working-directory: synapse
 
-      # Attempt to check out the same branch of Complement as the PR. If it
-      # doesn't exist, fallback to HEAD.
-      - name: Checkout complement
-        run: synapse/.ci/scripts/checkout_complement.sh
-
       - run: |
           set -o pipefail
           TEST_ONLY_SKIP_DEP_HASH_VERIFICATION=1 POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt