Is saying "O Muhammad, O Ali, O so-and-so" considered polytheism (shirk), even with the affirmation that they are not gods alongside Allah, and based on the hadith of the Companion who said "O Muhammad" for his leg numbness to be cured, and the slogan "O Muhammad!" in the battles of Muslims, and the saying of Yusuf's brothers "O our father, ask forgiveness for our sins"? And does Allah forgive those who commit polytheism (shirk)?

The saying "Ya Muhammad" falls into two categories:

First: A mere evocation of the addressed person without making a request, such as saying "Ya Muhammad, may Allah's peace and blessings be upon you." This is permissible and not polytheism (shirk).

Second: When the call involves an explicit or implicit request, such as "Ya Muhammad, do such and such," or seeking his help in lifting something heavy. This is polytheism with Allah the Almighty, because supplicating to the dead or the absent is polytheism, as indicated by the texts and the consensus of scholars, such as His saying, the Almighty: (And whoever invokes another deity with Allah, for whom he has no proof, then his account is only with his Lord. Indeed, the disbelievers will not succeed.) Al-Mu'minun/117.

The slogan "Ya Muhammadaah" has not been authentically reported in battles. If it did occur, it would be in the context of lamentation (nadbah), not seeking aid (istighathah), similar to Fatimah's saying "Wa Abtah" (Oh my father!) upon the Prophet's passing, peace and blessings be upon him.

Seeking supplication from a living, capable person, as Joseph's brothers did with their father Jacob by saying: (O our father, ask forgiveness for our sins) Yusuf/97, is permissible by the consensus of scholars.

The advice is to avoid this call or excessive use of it to prevent negative assumptions and to accustom the tongue to calling upon Allah the Almighty alone. Whoever falls into polytheism and then repents, Allah will accept his repentance.