Replace dual-approval with promotion gate workflow (#177)

New model: no review for dev PRs, QA gates uat, UAT gates main.
Replaces the old CTO+QA dual-approval check.

Co-authored-by: Chris Farhood <chris@farhood.org>
Co-authored-by: Paperclip <noreply@paperclip.ing>

.github/workflows/dual-approval-check.yaml

@@ -1,4 +1,4 @@
-name: Dual Approval Check
+name: Promotion Gate
 
 on:
   workflow_call:
@@ -7,38 +7,60 @@ on:
         description: "Pull request number"
         required: false
         type: number
-      cto-reviewer:
-        description: "GitHub username of the CTO reviewer"
-        required: false
-        type: string
-        default: "privilegedescalation-cto"
-      qa-reviewer:
-        description: "GitHub username of the QA reviewer"
-        required: false
-        type: string
-        default: "privilegedescalation-qa"
 
 jobs:
-  dual-approval:
-    name: Dual Approval (CTO + QA)
+  promotion-gate:
+    name: Promotion Gate
     runs-on: ubuntu-latest
     timeout-minutes: 5
 
     steps:
-      - name: Check dual approval
+      - name: Check promotion approval
         env:
           GH_TOKEN: ${{ github.token }}
-          CTO_REVIEWER: ${{ inputs.cto-reviewer }}
-          QA_REVIEWER: ${{ inputs.qa-reviewer }}
           PR_NUMBER: ${{ inputs.pr_number }}
           REPO: ${{ github.repository }}
+          BASE_REF: ${{ github.base_ref }}
         run: |
           if [ -z "${PR_NUMBER}" ] || [ "${PR_NUMBER}" = "null" ]; then
-            echo "::notice::No PR number in context (dismissed review or workflow_call without pr_number). Skipping dual approval check — no action needed."
+            echo "::notice::No PR number in context. Skipping promotion gate."
             exit 0
           fi
 
-          echo "Checking approvals on PR #${PR_NUMBER} in ${REPO}"
+          echo "Checking promotion gate for PR #${PR_NUMBER} targeting ${BASE_REF} in ${REPO}"
+
+          # Determine required reviewer based on target branch
+          case "${BASE_REF}" in
+            dev)
+              echo "Target is dev — no review required. Engineers self-merge."
+              exit 0
+              ;;
+            uat)
+              REQUIRED_REVIEWER="privilegedescalation-qa"
+              GATE_NAME="QA"
+              ;;
+            main)
+              REQUIRED_REVIEWER="privilegedescalation-qa"
+              GATE_NAME="QA"
+              # For plugin repos (Pipeline A), UAT approval is needed for uat→main
+              # Check if the source branch is uat
+              SOURCE_REF=$(curl -sf \
+                -H "Authorization: Bearer ${GH_TOKEN}" \
+                -H "Accept: application/vnd.github.v3+json" \
+                "https://api.github.com/repos/${REPO}/pulls/${PR_NUMBER}" | jq -r '.head.ref')
+
+              if [ "${SOURCE_REF}" = "uat" ]; then
+                REQUIRED_REVIEWER="privilegedescalation-uat"
+                GATE_NAME="UAT"
+              fi
+              ;;
+            *)
+              echo "::notice::Target branch '${BASE_REF}' has no promotion gate configured."
+              exit 0
+              ;;
+          esac
+
+          echo "Required reviewer: ${REQUIRED_REVIEWER} (${GATE_NAME})"
 
           REVIEWS=$(curl -sf \
             -H "Authorization: Bearer ${GH_TOKEN}" \
@@ -46,28 +68,18 @@ jobs:
             "https://api.github.com/repos/${REPO}/pulls/${PR_NUMBER}/reviews")
 
           if [ -z "${REVIEWS}" ] || [ "${REVIEWS}" = "null" ]; then
-            echo "::warning::Could not fetch reviews for PR #${PR_NUMBER}. Assuming no approvals yet."
+            echo "::warning::Could not fetch reviews for PR #${PR_NUMBER}."
             exit 1
           fi
 
-          CTO_APPROVED=$(echo "${REVIEWS}" | jq -r --arg user "${CTO_REVIEWER}" \
+          REVIEWER_APPROVED=$(echo "${REVIEWS}" | jq -r --arg user "${REQUIRED_REVIEWER}" \
             '[.[] | select(.user.login == $user or .user.login == ($user + "[bot]"))] | last | if .state then .state == "APPROVED" else false end')
 
-          QA_APPROVED=$(echo "${REVIEWS}" | jq -r --arg user "${QA_REVIEWER}" \
-            '[.[] | select(.user.login == $user or .user.login == ($user + "[bot]"))] | last | if .state then .state == "APPROVED" else false end')
+          echo "${GATE_NAME} (${REQUIRED_REVIEWER}) approved: ${REVIEWER_APPROVED}"
 
-          echo "CTO (${CTO_REVIEWER}) approved: ${CTO_APPROVED}"
-          echo "QA (${QA_REVIEWER}) approved: ${QA_APPROVED}"
-
-          if [ "${CTO_APPROVED}" = "true" ] && [ "${QA_APPROVED}" = "true" ]; then
-            echo "Both CTO and QA have approved. Dual approval check passed."
+          if [ "${REVIEWER_APPROVED}" = "true" ]; then
+            echo "Promotion gate passed: ${GATE_NAME} has approved."
           else
-            echo "Dual approval check failed."
-            if [ "${CTO_APPROVED}" != "true" ]; then
-              echo "  Missing: CTO approval from ${CTO_REVIEWER}"
-            fi
-            if [ "${QA_APPROVED}" != "true" ]; then
-              echo "  Missing: QA approval from ${QA_REVIEWER}"
-            fi
+            echo "Promotion gate failed: waiting for ${GATE_NAME} approval from ${REQUIRED_REVIEWER}."
             exit 1
-          fi
+          fi