fix(mosaic): harden gitea pr wrapper metadata

packages/mosaic/framework/tools/git/pr-merge.sh

@@ -1,10 +1,11 @@
 #!/bin/bash
 # pr-merge.sh - Merge pull requests on Gitea or GitHub
-# Usage: pr-merge.sh -n PR_NUMBER [-m squash] [-d] [--skip-queue-guard]
+# Usage: pr-merge.sh -n PR_NUMBER [-m squash] [-d] [--skip-queue-guard] [--dry-run]
 
 set -e
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck disable=SC1091
 source "$SCRIPT_DIR/detect-platform.sh"
 
 # Default values
@@ -12,6 +13,7 @@ PR_NUMBER=""
 MERGE_METHOD="squash"
 DELETE_BRANCH=false
 SKIP_QUEUE_GUARD=false
+DRY_RUN=false
 
 usage() {
     cat <<EOF
@@ -24,6 +26,7 @@ Options:
     -m, --method METHOD     Merge method: squash only (default: squash)
     -d, --delete-branch     Delete the head branch after merge
         --skip-queue-guard  Skip CI queue guard wait before merge
+        --dry-run           Validate metadata/auth/preflight without merging
     -h, --help              Show this help message
 
 Examples:
@@ -54,6 +57,10 @@ while [[ $# -gt 0 ]]; do
             SKIP_QUEUE_GUARD=true
             shift
             ;;
+        --dry-run)
+            DRY_RUN=true
+            shift
+            ;;
         -h|--help)
             usage
             ;;
@@ -74,7 +81,8 @@ if [[ "$MERGE_METHOD" != "squash" ]]; then
     exit 1
 fi
 
-BASE_BRANCH="$("$SCRIPT_DIR/pr-metadata.sh" -n "$PR_NUMBER" | python3 -c 'import json, sys; print((json.load(sys.stdin).get("baseRefName") or "").strip())')"
+METADATA_JSON="$("$SCRIPT_DIR/pr-metadata.sh" -n "$PR_NUMBER")"
+BASE_BRANCH="$(printf '%s' "$METADATA_JSON" | python3 -c 'import json, sys; print((json.load(sys.stdin).get("baseRefName") or "").strip())')"
 if [[ "$BASE_BRANCH" != "main" ]]; then
     echo "Error: Mosaic policy allows merges only for PRs targeting 'main' (found '$BASE_BRANCH')." >&2
     exit 1
@@ -94,19 +102,55 @@ REPO=$(get_repo_name)
 
 case "$PLATFORM" in
     github)
-        CMD="gh pr merge $PR_NUMBER --squash"
-        [[ "$DELETE_BRANCH" == true ]] && CMD="$CMD --delete-branch"
-        eval "$CMD"
+        if [[ "$DRY_RUN" == true ]]; then
+            echo "Dry run: GitHub merge preflight OK for ${OWNER}/${REPO}#${PR_NUMBER} targeting ${BASE_BRANCH}"
+            exit 0
+        fi
+        CMD=(gh pr merge "$PR_NUMBER" --squash)
+        [[ "$DELETE_BRANCH" == true ]] && CMD+=(--delete-branch)
+        "${CMD[@]}"
         ;;
     gitea)
-        CMD="tea pr merge $PR_NUMBER --style squash --repo $OWNER/$REPO --login ${GITEA_LOGIN:-mosaicstack}"
+        HOST=$(get_remote_host) || {
+            echo "Error: Cannot determine host from remote URL" >&2
+            exit 1
+        }
+        TOKEN=$(get_gitea_token "$HOST") || {
+            echo "Error: Could not resolve Gitea API token for ${HOST}" >&2
+            exit 1
+        }
+
+        if [[ "$DRY_RUN" == true ]]; then
+            echo "Dry run: Gitea merge preflight OK for ${OWNER}/${REPO}#${PR_NUMBER} targeting ${BASE_BRANCH} via ${HOST} API"
+            exit 0
+        fi
+
+        RESPONSE_FILE=$(mktemp)
+        trap 'rm -f "$RESPONSE_FILE"' EXIT
+        HTTP_CODE=$(curl -sS \
+            -X POST \
+            -H "Authorization: token $TOKEN" \
+            -H "Content-Type: application/json" \
+            -d '{"Do":"squash"}' \
+            -o "$RESPONSE_FILE" \
+            -w '%{http_code}' \
+            "https://${HOST}/api/v1/repos/${OWNER}/${REPO}/pulls/${PR_NUMBER}/merge")
+        RESPONSE_BODY=$(cat "$RESPONSE_FILE")
+        rm -f "$RESPONSE_FILE"
+        trap - EXIT
+
+        if [[ ! "$HTTP_CODE" =~ ^2 ]]; then
+            echo "Error: Gitea PR merge failed for ${OWNER}/${REPO}#${PR_NUMBER} (HTTP ${HTTP_CODE})" >&2
+            if [[ -n "$RESPONSE_BODY" ]]; then
+                printf '%s\n' "$RESPONSE_BODY" >&2
+            fi
+            exit 1
+        fi
 
         # Delete branch after merge if requested
         if [[ "$DELETE_BRANCH" == true ]]; then
-            echo "Note: Branch deletion after merge may need to be done separately with tea" >&2
+            echo "Note: Branch deletion after merge may need to be done separately with the Gitea API" >&2
         fi
-
-        eval "$CMD"
         ;;
     *)
         echo "Error: Could not detect git platform" >&2