API: Validate empty filter list

CHANGELOG.md

@@ -25,6 +25,7 @@ All notable changes to this project will be documented in this file.
 
 ### Fixed
 
+- Validate empty filter clauses list in Stats API v2
 - Fixed Stats API timeseries returning time buckets falling outside the queried range
 - Fixed issue with all non-interactive events being counted as interactive
 - Fixed countries map countries staying highlighted on Chrome

assets/js/types/query-api.d.ts

@@ -90,7 +90,10 @@ export type FilterWithoutGoals =
  * filter operation
  */
 export type FilterOperationWithoutGoals = "is_not" | "contains_not";
-export type Clauses = (string | number)[];
+/**
+ * @minItems 1
+ */
+export type Clauses = [string | number, ...(string | number)[]];
 /**
  * @minItems 3
  * @maxItems 4

priv/json-schemas/query-api-schema.json

@@ -316,6 +316,7 @@
     },
     "clauses": {
       "type": "array",
+      "minItems": 1,
       "items": {
         "type": ["string", "integer"]
       }