fc5: strip SQLAlchemy +psycopg/+asyncpg driver suffix when passing URL to pg_dump/psql

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/app/services/migrators/backup.py

@@ -16,6 +16,19 @@ from typing import Any
 _BACKUPS_DIRNAME = "_backups"
 
 
+def _libpq_url(sa_url: str) -> str:
+    """Strip SQLAlchemy driver suffix so pg_dump/psql accept the URL.
+
+    SQLAlchemy uses URLs like `postgresql+psycopg://...` or
+    `postgresql+asyncpg://...`. libpq tools (pg_dump, psql) only know
+    the plain `postgresql://` scheme.
+    """
+    for driver in ("postgresql+psycopg", "postgresql+asyncpg", "postgresql+psycopg2"):
+        if sa_url.startswith(driver + "://"):
+            return "postgresql://" + sa_url[len(driver) + 3:]
+    return sa_url
+
+
 def _backups_dir(images_root: Path | None = None) -> Path:
     # Overridable for tests via monkeypatch.
     root = images_root if images_root is not None else Path("/images")
@@ -49,7 +62,7 @@ def create_backup(
     manifest_path = out_dir / f"fc_{ts}.json"
 
     _run_subprocess(
-        ["pg_dump", "--no-owner", "--no-acl", "-f", str(sql_path), db_url],
+        ["pg_dump", "--no-owner", "--no-acl", "-f", str(sql_path), _libpq_url(db_url)],
         _test_ts=ts,
     )
     _run_subprocess(
@@ -104,7 +117,7 @@ def restore_backup(
     tar_path = Path(manifest["tar_path"])
 
     _run_subprocess(
-        ["psql", "-d", db_url, "-f", str(sql_path)],
+        ["psql", "-d", _libpq_url(db_url), "-f", str(sql_path)],
     )
 
     # Wipe everything in images_root EXCEPT _backups/ (we'd delete the backup