Ash-Shahrastani about the name Umar for the son of Ali

Ali Ibn Abdi r-Rida Ash-Shahrastani writes:

أَمَّـا وَضْـعُ اسْـمِ عُـمَـرَ عَـلَـى أَحَـدِ أَوْلَادِهِ فَـقَـدْ كَـانَ مِـنْ قِـبَـلِ عُـمَـرَ بْـنِ الْـخَـطَّـابِ لَا مِـنْـهُ عَـلَـيْـهِ الـسَّـلَامُ فَـقَـدْ جَـاءَ فِـي تَـارِيـخِ الْـمَـدِيـنَـةِ لِابْـنِ شَـبَّـةَ الـنُّـمَـيْـرِيِّ: حَـدَّثَـنَـا عِـيـسَـى بْـنُ عَـبْـدِ الـلَّـهِ بْـنِ مُـحَـمَّـدِ بْـنِ عُـمَـرَ بْـنِ عَـلِـيِّ بْـنِ أَبِـي طَـالِـبٍ قَـالَ حَـدَّثَـنِـي أَبِـي عَـنْ أَبِـيـهِ عَـنْ عَـلِـيِّ بْـنِ أَبِـي طَـالِـبٍ عَـلَـيْـهِ الـسَّـلَامُ قَـالَ: وُلِـدَ لِـي غُـلَامٌ يَـوْمَ قَـامَ عُـمَـرُ فَـغَـدَوْتُ عَـلَـيْـهِ فَـقُـلْـتُ لَـهُ: وُلِـدَ لِـي غُـلَامٌ هَـذِهِ الـلَّـيْـلَـةَ قَـالَ: مِـمَّـنْ؟ قُـلْـتُ: مِـنَ الـتَّـغْـلِـبِـيَّـةِ قَـالَ: فَـهَـبْ لِـي اسْـمَـهُ قُـلْـتُ: نَـعَـمْ قَـالَ: فَـقَـدْ سَـمَّـيْـتُـهُ بِـاسْـمِـي وَنَـحَـلْـتُـهُ غَـلَامِـي مَـوْرِكًـا قَـال: وَكَـانَ نُـوبِـيًّـا قَـالَ: فَـأَعْـتَـقَـهُ عُـمَـرُ بْـنُ عَـلِـيٍّ بَـعْـدَ ذَلِـكَ فَـوُلْـدُهُ الْـيَـوْمَ مَـواَلِـيـهِ وَالْإِمَـامُ اسْـتَـجَـابَ لِـطَـلَـبِ عُـمَـرَ لَأَنَّـهُ عَـلَـيْـهِ الـسَّـلَامُ لَـوْ لَـمْ يَـقْـبَـلْ بِـذَلِـكَ لَـتَـسَـبَّـبَـتْ لَـهُ مَـشَـاكِـلُ كَـثِـيـرَةٌ كَـانَ هُـوَ فِـي غِـنًـى عَـنْـهَـا لَأَنَّ الْإِسْـلَامَ كَـانَ فِـي مَـرْحَـلَـةِ الـتَّـأْسِـيـسِ وَعَـلَـيْـهِ الْـحِـفَـاظُ عَـلَـى بَـيْـضَـةِ الْإِسْـلَامِ وَذَلِـكَ لِـمَـعْـرِفَـتِـهِ بَـأَهْـدَافِ وَتَـوَجُّـهَـاتِ الْـخُـلَـفَـاءِ وَالَّـتِـي سَـنُـشِـيـرُ إِلَـى بَـعْـضِـهَـا مُـفَـصَّـلًا فِـي الـسَّـيْـرِ الـتَّـارِيـخِـيِّ لِـهَـذِهِ الْـمَـسَـأَلَـةِ

,,As for the naming of Umar to one of his children, that has come about from Umar, not from him (a.), for it has been reported in Tarikh-ul-Madinah from Ibn Shabbah An-Numairi: We were told by Isa Ibn Abdillah Ibn Muhammad Ibn Umar Ibn Ali Ibn Abi Talib who said: ,,I was told by my father, by his father, by Ali Ibn Abi Talib who said: ﴾On the day, when Umar arose, a boy was born to me. So I went to him early in the morning and said: ,,A boy has been born to me this night.” He said: ,,From whom?” I said: ,,By the Taghlibitin.” He said: ,,Then let me name him.” I said: ,,Yes.” He said: ,,I have given him my name and I have gifted him my lad as a stirrup.”﴿ He said: ﴾And he was a Nubian.﴿ He said: ﴾Umar, the son of Ali, released him hereupon. So his descendants are his clients today.﴿ And the Imam (a.) fulfilled the request of Umar, because it would have caused him many unnecessary problems if he had not accepted it, because Islam was in its formative stage and he had to keep the community of Islam together and that because of his knowledge of the objectives and orientations of the followers and because of that, which we will show in detail for the historical course of this matter.” [At-Tasmiyyat, page 7]