Sounds like you will be tax resident in both countries, and liable to tax in both countries, but with double tax relief available.
Has your company not obtained tax advice for you?
Have they agreed to do this? Will they pay for this? Are they going to operate payroll procedures in Poland for you?
If the answers to the above questions are no, you should seek your own tax advice, as your situation will be complex.
1) If you spend 183 days or more in any tax year (I assume you will not be caught under this one), and
2) If you spend 280 days or more over 2 consecutive years, you will be considered resident in Ireland in the second year - This will probably apply to you.
You will probably not break Irish residence for at least a tax year after you leave, and will therefore have double tax issues.
You should really take professional advice in this regard.