SET parser: stops after SET NAMES when comma-separated assignments follow

[renecannao]

Problem

When a SET statement contains SET NAMES charset followed by comma-separated variable assignments (e.g., SET NAMES utf8, sql_mode = 'TRADITIONAL'), the parser stops after SET NAMES and does not parse the remaining assignments.

Failing test cases

SET sql_mode = 'TRADITIONAL', NAMES 'utf8' COLLATE 'unicode_ci'
  Expected: {"sql_mode": ["TRADITIONAL"], "names": ["utf8", "unicode_ci"]}
  Got:      {"sql_mode": ["TRADITIONAL"]}  (names missing)

SET NAMES utf8, @@SESSION.sql_mode = CONCAT(...), @@SESSION.sql_auto_is_null = 0, @@SESSION.wait_timeout = 3600
  Expected: 4 entries (names + 3 assignments)
  Got:      1 entry (names only)

SET NAMES utf8, @@LOCAL.sql_mode = CONCAT(...), @@LOCAL.sql_auto_is_null = 0, @@LOCAL.wait_timeout = 3600
  Expected: 4 entries
  Got:      1 entry (names only)

SET NAMES utf8, @@SESSION.sql_mode = CONCAT(CONCAT(REPLACE(...))), @@SESSION.sql_auto_is_null = 0, @@SESSION.wait_timeout = 3600
  Expected: 4 entries
  Got:      1 entry (names only)

Root cause

In set_parser.h, after parsing NODE_SET_NAMES, the parser does not continue to check for comma-separated NODE_VAR_ASSIGNMENT siblings. The SetParser returns after the NAMES clause.

Expected behavior

SET NAMES charset [, var = expr, ...] should produce both a NODE_SET_NAMES child and NODE_VAR_ASSIGNMENT children under the NODE_SET_STMT root.

Context

Discovered during integration testing of ParserSQL into ProxySQL. Test suite: setparser_test_common.h, test arrays multiple[2], multiple[6], multiple[7], Set1_v2[1].