bad access: nil dereference while debug example_test

[jyno12]

github.com/pingcap/tidb/ddl/ddl.go

	// Notice worker that we push a new job and wait the job done.
	d.asyncNotifyWorker(job.Type)
	logutil.BgLogger().Info("[ddl] start DDL job", zap.String("job", job.String()), zap.String("query", job.Query))

while job.String panic
pingcap/parser#577

[WangXiangUSTC]

OK, after this pr merged, I will update the mod

[WangXiangUSTC]

fixed in #15, please try again