Muwatta Malik, Book 29, Hadith 1259 (In-Book) ⓘ

Yahya related to me the like of that from Malik from Ibn Shihab. Malik said, about a slave who divorced a slave-girl but did not make it absolute, "He can return to her. If he then dies while she is still in the idda from her divorce, she does the idda of a slave- girl whose husband dies, and it is two months and five days. If she has been set free and he can return to her, and she does not choose to separate after she has been set free, and he dies while she is in the idda from the divorce, she does the idda of a free woman whose husband has died, four months and ten days. That is because the idda of widowhood befell her while she was free, so her idda is the idda of a free woman." Malik said, "That is what is done among us."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، مِثْلَ ذَلِكَ ‏.‏ قَالَ مَالِكٌ فِي الْعَبْدِ يُطَلِّقُ الأَمَةَ طَلاَقًا لَمْ يَبُتَّهَا فِيهِ لَهُ عَلَيْهَا فِيهِ الرَّجْعَةُ ثُمَّ يَمُوتُ وَهِيَ فِي عِدَّتِهَا مِنْ طَلاَقِهِ إِنَّهَا تَعْتَدُّ عِدَّةَ الأَمَةِ الْمُتَوَفَّى عَنْهَا زَوْجُهَا شَهْرَيْنِ وَخَمْسَ لَيَالٍ وَإِنَّهَا إِنْ عَتَقَتْ وَلَهُ عَلَيْهَا رَجْعَةٌ ثُمَّ لَمْ تَخْتَرْ فِرَاقَهُ بَعْدَ الْعِتْقِ حَتَّى يَمُوتَ وَهِيَ فِي عِدَّتِهَا مِنْ طَلاَقِهِ اعْتَدَّتْ عِدَّةَ الْحُرَّةِ الْمُتَوَفَّى عَنْهَا زَوْجُهَا أَرْبَعَةَ أَشْهُرٍ وَعَشْرًا وَذَلِكَ أَنَّهَا إِنَّمَا وَقَعَتْ عَلَيْهَا عِدَّةُ الْوَفَاةِ بَعْدَ مَا عَتَقَتْ فَعِدَّتُهَا عِدَّةُ الْحُرَّةِ ‏.‏ قَالَ مَالِكٌ وَهَذَا الأَمْرُ عِنْدَنَا ‏.‏