Adds project_routing query param to _msearch Elasticsearch API

Author: quux00

output/openapi/elasticsearch-openapi.json

@@ -18,7 +18,13 @@
  */
 
 import { RequestBase } from '@_types/Base'
-import { ExpandWildcards, Indices, Routing, SearchType } from '@_types/common'
+import {
+  ExpandWildcards,
+  Indices,
+  ProjectRouting,
+  Routing,
+  SearchType
+} from '@_types/common'
 import { integer, long } from '@_types/Numeric'
 import { RequestItem } from './types'
 
@@ -117,6 +123,17 @@ export interface Request extends RequestBase {
      * Defines a threshold that enforces a pre-filter roundtrip to prefilter search shards based on query rewriting if the number of shards the search request expands to exceeds the threshold. This filter roundtrip can limit the number of shards significantly if for instance a shard can not match any documents based on its rewrite method i.e., if date filters are mandatory to match but the shard bounds and the query are disjoint.
      */
     pre_filter_shard_size?: long
+    /**
+     * Specifies a subset of projects to target for a search using project metadata
+     * tags in a subset Lucene syntax. Allowed Lucene queries: the _alias tag
+     * and a single value (possible wildcarded). Examples:
+     *  _alias:my-project
+     *  _alias:_origin
+     *  _alias:*pr*
+     * Supported in serverless only.
+     * @availability serverless stability=stable visibility=feature_flag feature_flag=serverless.cross_project.enabled
+     */
+    project_routing?: ProjectRouting
     /**
      * If true, hits.total are returned as an integer in the response. Defaults to false, which returns an object.
      * @server_default false

output/openapi/elasticsearch-serverless-openapi.json

@@ -18,7 +18,13 @@
  */
 
 import { ErrorResponseBase } from '@_types/Base'
-import { ExpandWildcards, Indices, Routing, SearchType } from '@_types/common'
+import {
+  ExpandWildcards,
+  Indices,
+  ProjectRouting,
+  Routing,
+  SearchType
+} from '@_types/common'
 import { integer, long } from '@_types/Numeric'
 import { SearchRequestBody } from '@global/search/_types/SearchRequestBody'
 import { ResponseBody as SearchResponse } from '@global/search/SearchResponse'
@@ -37,6 +43,7 @@ export class MultisearchHeader {
   ignore_unavailable?: boolean
   index?: Indices
   preference?: string
+  project_routing?: ProjectRouting
   request_cache?: boolean
   routing?: Routing
   search_type?: SearchType

output/schema/schema.json

@@ -84,6 +84,10 @@
         "default": "open",
         "description": "Whether to expand wildcard expression to concrete indices that are open, closed or both."
       },
+      "project_routing": {
+        "type": "string",
+        "description": "A Lucene query using project metadata tags to limit which projects to search, such as _alias:_origin or _alias:*pr*. Only supported in serverless."
+      },
       "routing": {
         "type": "list",
         "description": "A comma-separated list of specific routing values"