Tests the test-upgrade scripts themselves (#10664)

## Problem
We run the compatibility tests only if we are upgrading the extension.
An accidental code change may break the test itself, so we have to check
this code as well.
## Summary of changes
The test is scheduled once a day to save time and resources.

---------

Co-authored-by: Alexander Bayandin <alexander@neon.tech>

.github/workflows/force-test-extensions-upgrade.yml

@@ -0,0 +1,76 @@
+name: Force Test Upgrading of Extension
+on:
+  schedule:
+    # * is a special character in YAML so you have to quote this string
+    #          ┌───────────── minute (0 - 59)
+    #          │ ┌───────────── hour (0 - 23)
+    #          │ │ ┌───────────── day of the month (1 - 31)
+    #          │ │ │ ┌───────────── month (1 - 12 or JAN-DEC)
+    #          │ │ │ │ ┌───────────── day of the week (0 - 6 or SUN-SAT)
+    - cron:  '45 2 * * *' # run once a day, timezone is utc
+  workflow_dispatch: # adds ability to run this manually
+
+defaults:
+  run:
+    shell: bash -euxo pipefail {0}
+
+concurrency:
+  # Allow only one workflow
+  group: ${{ github.workflow }}
+  cancel-in-progress: true
+
+permissions:
+  id-token: write # aws-actions/configure-aws-credentials
+  statuses: write
+  contents: read
+
+jobs:
+  regress:
+    strategy:
+      fail-fast: false
+      matrix:
+        pg-version: [16, 17]
+
+    runs-on: small
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: false
+
+      - name: Get the last compute release tag
+        id: get-last-compute-release-tag
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          tag=$(gh api -q '[.[].tag_name | select(startswith("release-compute"))][0]'\
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            "/repos/${GITHUB_REPOSITORY}/releases")
+          echo tag=${tag} >> ${GITHUB_OUTPUT}
+
+      - name: Test extension upgrade
+        timeout-minutes: 20
+        env:
+          NEWTAG: latest
+          OLDTAG: ${{ steps.get-last-compute-release-tag.outputs.tag }}
+          PG_VERSION: ${{ matrix.pg-version }}
+          FORCE_ALL_UPGRADE_TESTS: true
+        run: ./docker-compose/test_extensions_upgrade.sh
+
+      - name: Print logs and clean up
+        if: always()
+        run: |
+          docker compose --profile test-extensions -f ./docker-compose/docker-compose.yml logs || true
+          docker compose --profile test-extensions -f ./docker-compose/docker-compose.yml down
+
+      - name: Post to the Slack channel
+        if: ${{ github.event.schedule && failure() }}
+        uses: slackapi/slack-github-action@v1
+        with:
+          channel-id: ${{ vars.SLACK_ON_CALL_QA_STAGING_STREAM }}
+          slack-message: |
+            Test upgrading of extensions: ${{ job.status }}
+            <${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}|GitHub Run>
+        env:
+          SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}

docker-compose/test_extensions_upgrade.sh

@@ -11,6 +11,7 @@ if [ -z ${OLDTAG+x} ] || [ -z ${NEWTAG+x} ] || [ -z "${OLDTAG}" ] || [ -z "${NEW
   exit 1
 fi
 export PG_VERSION=${PG_VERSION:-16}
+export PG_TEST_VERSION=${PG_VERSION}
 function wait_for_ready {
   TIME=0
   while ! docker compose logs compute_is_ready | grep -q "accepting connections" && [ ${TIME} -le 300 ] ; do
@@ -59,8 +60,12 @@ docker compose cp  ext-src neon-test-extensions:/
 docker compose exec neon-test-extensions psql -c "DROP DATABASE IF EXISTS contrib_regression"
 docker compose exec neon-test-extensions psql -c "CREATE DATABASE contrib_regression"
 create_extensions "${EXTNAMES}"
-query="select pge.extname from pg_extension pge join (select key as extname, value as extversion from json_each_text('${new_vers}')) x on pge.extname=x.extname and pge.extversion <> x.extversion"
-exts=$(docker compose exec neon-test-extensions psql -Aqt -d contrib_regression -c "$query")
+if [ "${FORCE_ALL_UPGRADE_TESTS:-false}" = true ]; then
+  exts="${EXTNAMES}"
+else
+  query="select pge.extname from pg_extension pge join (select key as extname, value as extversion from json_each_text('${new_vers}')) x on pge.extname=x.extname and pge.extversion <> x.extversion"
+  exts=$(docker compose exec neon-test-extensions psql -Aqt -d contrib_regression -c "$query")
+fi
 if [ -z "${exts}" ]; then
   echo "No extensions were upgraded"
 else
@@ -88,7 +93,10 @@ else
       exit 1
     fi
     docker compose exec neon-test-extensions psql -d contrib_regression -c "\dx ${ext}"
-    docker compose exec neon-test-extensions sh -c /ext-src/${EXTDIR}/test-upgrade.sh
+    if ! docker compose exec neon-test-extensions sh -c /ext-src/${EXTDIR}/test-upgrade.sh; then
+      docker  compose exec neon-test-extensions  cat /ext-src/${EXTDIR}/regression.diffs
+      exit 1
+    fi
     docker compose exec neon-test-extensions psql -d contrib_regression -c "alter extension ${ext} update"
     docker compose exec neon-test-extensions psql -d contrib_regression -c "\dx ${ext}"
   done