Fixed number rows validation

Author: GrigoriyPA

ydb/core/fq/libs/row_dispatcher/json_parser.cpp

@@ -177,8 +177,8 @@ class TJsonParser::TImpl {
                 }
                 rowId++;
             }
-            if (rowId < Buffer.NumberValues) {
-                throw yexception() << "Failed to parse json messages, expected " << Buffer.NumberValues << " json rows but got " << rowId;
+            if (rowId != Buffer.NumberValues) {
+                throw yexception() << "Failed to parse json messages, expected " << Buffer.NumberValues << " json rows from offset " << Buffer.Offsets.front() << " but got " << rowId;
             }
 
             for (size_t i = 0; i < Columns.size(); ++i) {

ydb/core/fq/libs/row_dispatcher/ut/json_parser_ut.cpp

@@ -235,8 +235,9 @@ Y_UNIT_TEST_SUITE(TJsonParserTests) {
     }
 
     Y_UNIT_TEST_F(ThrowExceptionByError, TFixture) {
-        MakeParser({"a2", "a1"});
+        MakeParser({"a"});
         UNIT_ASSERT_EXCEPTION_CONTAINS(PushToParser(42, R"(ydb)"), simdjson::simdjson_error, "INCORRECT_TYPE: The JSON element does not have the requested type.");
+        UNIT_ASSERT_EXCEPTION_CONTAINS(PushToParser(42, R"({"a": "value1"} {"a": "value2"})"), yexception, "Failed to parse json messages, expected 1 json rows from offset 42 but got 2");
     }
 }