message: added guard for null id in pgsearch
diff: @@ -199,6 +199,11 @@ class Batch {
  async saveDocument(context) {
  let { schema, branch, type, id, sourceId, generation, upstreamDoc, _read:read } = context;
  + if (id == null) {
  + log.warn(`pgsearch cannot save document without id ${JSON.stringify(upstreamDoc)}`);
  + return;
  + }
  +
  let searchDoc = await context.searchDoc();
  let pristineDoc = await context.pristineDoc();
  let refs = await context.references();
  