add-promotion-gate-action: Add git/promotion-gate composite action

Enforces which source branches may merge into which target branches, configured via a rules input (one target:allowed,allowed per line, glob-capable). Empty rules (default) skips enforcement entirely, so repos can adopt it without immediately gating on rules they have not configured. Extracted for reuse across repos moving to a gitflow-style branch promotion model, starting with stat-tackler-api.
2026-08-21 14:57:03 -04:00
parent 50dc06f634
commit 4e765e5c64
4 changed files with 98 additions and 0 deletions
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+name: Promotion Gate
+description: Enforce which source branches may merge into which target branches
+inputs:
+  rules:
+    description: |
+      One rule per line: "target:allowed1,allowed2,...". Targets not
+      listed are unrestricted. Allowed entries may use a trailing glob,
+      e.g. `hotfix-*`. Leave empty (default) to skip entirely.
+    default: ""
+
+runs:
+  using: composite
+  steps:
+    - name: Check merge source is allowed for target branch
+      shell: sh
+      env:
+        BASE: ${{ gitea.event.pull_request.base.ref }}
+        HEAD: ${{ gitea.event.pull_request.head.ref }}
+        RULES: ${{ inputs.rules }}
+      run: |
+        if [ -z "$RULES" ]; then
+          echo "No promotion rules configured — skipping."
+          exit 0
+        fi
+
+        rc=0
+        found=0
+
+        oldIFS=$IFS
+        IFS='
+        '
+        set -f
+        set -- $RULES
+        set +f
+        IFS=$oldIFS
+
+        for line in "$@"; do
+          if [ -z "$line" ]; then
+            continue
+          fi
+          target=${line%%:*}
+          allowed=${line#*:}
+          if [ "$target" = "$line" ]; then
+            continue
+          fi
+          if [ "$BASE" = "$target" ]; then
+            found=1
+            matched=0
+            innerIFS=$IFS
+            IFS=','
+            for pat in $allowed; do
+              IFS=$innerIFS
+              case "$HEAD" in
+                $pat)
+                  matched=1
+                  ;;
+              esac
+              IFS=','
+            done
+            IFS=$innerIFS
+
+            if [ "$matched" -eq 1 ]; then
+              echo "Allowed: '$HEAD' -> '$BASE' (matches: $allowed)"
+            else
+              echo "::error::$BASE only accepts merges from: $allowed — got '$HEAD'"
+              rc=1
+            fi
+          fi
+        done
+
+        if [ "$found" -eq 0 ]; then
+          echo "No promotion-source restriction configured for base '$BASE'"
+        fi
+
+        exit $rc