Dear Aspirant

Hope you are doing well

If you are asking about Indian engineering service

Diabetes is of two types type 1 and type 2.Normally a person with type 1 diabetes have to take insulin as per the doctors advice and that too everyday. In type 2 there is no such problem you have to just maintain your diet

According their test says

The  urine  test  should  test  negative  to  sugar,  but  if  in  case  medical  board  finds  sugar  then  the  case  will  be  proceed  for  further examination. If standards of medical fitness are met then they pass candidate as fit.

If  it  is  the  case  of  Glycosuria  then  after  further  examinations  and  tests  medical  board  will  come  to  their  conclusion.  Candidate having Diabetes Mellitus is declared unfit

According to me due to this you might face problem