fix(mosaic): harden Gitea pr merge fallback (#520)

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

@@ -2,9 +2,10 @@
 # pr-merge.sh - Merge pull requests on Gitea or GitHub
 # Usage: pr-merge.sh -n PR_NUMBER [-m squash] [-d] [--skip-queue-guard]
 
-set -e
+set -euo pipefail
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=packages/mosaic/framework/tools/git/detect-platform.sh
 source "$SCRIPT_DIR/detect-platform.sh"
 
 # Default values
@@ -92,6 +93,101 @@ PLATFORM=$(detect_platform)
 OWNER=$(get_repo_owner)
 REPO=$(get_repo_name)
 
+find_tea_login_for_host() {
+    local host="$1"
+    local logins_json
+
+    command -v tea >/dev/null 2>&1 || return 1
+    logins_json=$(tea login list --output json 2>/dev/null) || return 1
+    TEA_LOGINS_JSON="$logins_json" python3 - "$host" <<'PY'
+import json
+import os
+import sys
+
+host = sys.argv[1]
+try:
+    logins = json.loads(os.environ.get("TEA_LOGINS_JSON", "[]"))
+except Exception:
+    raise SystemExit(1)
+
+for login in logins if isinstance(logins, list) else []:
+    url = str(login.get("url") or login.get("URL") or "")
+    name = str(login.get("name") or login.get("Name") or "")
+    if url.rstrip("/").endswith(host) and name:
+        print(name)
+        raise SystemExit(0)
+
+raise SystemExit(1)
+PY
+}
+
+is_known_tea_empty_identity_failure() {
+    local error_file="$1"
+
+    python3 - "$error_file" <<'PY'
+import re
+import sys
+
+with open(sys.argv[1], encoding="utf-8", errors="replace") as handle:
+    error = handle.read()
+
+known_empty_identity = re.search(
+    r"user does not exist.*\[.*uid:\s*0,\s*name:\s*\]",
+    error,
+    flags=re.IGNORECASE | re.DOTALL,
+)
+raise SystemExit(0 if known_empty_identity else 1)
+PY
+}
+
+merge_gitea_with_api() {
+    local host="$1"
+    local api_url="https://${host}/api/v1/repos/${OWNER}/${REPO}/pulls/${PR_NUMBER}/merge"
+    local token body_file payload
+
+    token=$(get_gitea_token "$host" || true)
+    if [[ -z "$token" ]]; then
+        echo "Error: No Gitea API token available for authenticated merge fallback on $host." >&2
+        return 1
+    fi
+
+    mkdir -p "${AGENT_WORK_ROOT:-/home/hermes/agent-work}"
+    body_file=$(mktemp "${AGENT_WORK_ROOT:-/home/hermes/agent-work}/pr-merge-api-response.XXXXXX")
+    payload='{"Do":"squash"}'
+
+    if curl -fsS \
+        -X POST \
+        -H "Authorization: token $token" \
+        -H 'Content-Type: application/json' \
+        -d "$payload" \
+        "$api_url" > "$body_file"; then
+        rm -f "$body_file"
+        return 0
+    fi
+
+    python3 - "$body_file" <<'PY' >&2
+import json
+import sys
+
+path = sys.argv[1]
+try:
+    with open(path, encoding="utf-8", errors="replace") as handle:
+        raw = handle.read(500)
+    data = json.loads(raw) if raw else {}
+    message = data.get("message") or data.get("error") or raw or "empty response"
+except Exception:
+    try:
+        with open(path, encoding="utf-8", errors="replace") as handle:
+            message = handle.read(500) or "empty response"
+    except Exception:
+        message = "unreadable response"
+
+print(f"Error: Gitea API merge fallback failed: {message}")
+PY
+    rm -f "$body_file"
+    return 1
+}
+
 case "$PLATFORM" in
     github)
         CMD="gh pr merge $PR_NUMBER --squash"
@@ -99,14 +195,36 @@ case "$PLATFORM" in
         eval "$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 origin remote URL" >&2
+            exit 1
+        }
+        TEA_LOGIN="${GITEA_LOGIN:-$(find_tea_login_for_host "$HOST" || true)}"
 
         # 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
         fi
 
-        eval "$CMD"
+        if [[ -n "$TEA_LOGIN" ]]; then
+            mkdir -p "${AGENT_WORK_ROOT:-/home/hermes/agent-work}"
+            TEA_ERROR_FILE=$(mktemp "${AGENT_WORK_ROOT:-/home/hermes/agent-work}/pr-merge-tea-error.XXXXXX")
+            if tea pr merge "$PR_NUMBER" --style squash --repo "$OWNER/$REPO" --login "$TEA_LOGIN" 2> "$TEA_ERROR_FILE"; then
+                rm -f "$TEA_ERROR_FILE"
+            elif is_known_tea_empty_identity_failure "$TEA_ERROR_FILE"; then
+                cat "$TEA_ERROR_FILE" >&2
+                echo "Known tea empty identity failure detected; using authenticated Gitea API merge fallback." >&2
+                rm -f "$TEA_ERROR_FILE"
+                merge_gitea_with_api "$HOST"
+            else
+                cat "$TEA_ERROR_FILE" >&2
+                rm -f "$TEA_ERROR_FILE"
+                exit 1
+            fi
+        else
+            echo "No tea login configured for $HOST; using authenticated Gitea API merge fallback." >&2
+            merge_gitea_with_api "$HOST"
+        fi
         ;;
     *)
         echo "Error: Could not detect git platform" >&2