The Messenger of Allah ﷺ set out during the year of the Conquest in Ramadan, fasting, and the Muslims fasted along with him. When he reached al-Kadid, he called for water in a wooden bowl while he was on his mount and drank it as the people watched, letting them know that he had broken his fast. So the Muslims broke their fast as well.
حدثنا يعقوب قال حدثنا أبي عن ابن إسحاق حدثني بشير بن يسار مولى بني حارثة
خرج رسول الله ﷺ عام الفتح في رمضان فصام وصام المسلمون معه حتى إذا كان بالكديد دعا بماء في قعب وهو على راحلته فشرب والناس ينظرون يعلمهم أنه قد أفطر فأفطر المسلمون
Its isnad is sahih. Bashir, diminutive form, bin Yasar Ansari, client of Banu Haritha, is a trustworthy successor (tabii). Ibn Saad said in 5:223, "He was an elderly scholar well versed in jurisprudence, and he had met most of the companions of the Messenger of Allah ﷺ." The authors of the six books narrated from him, and Bukhari gave his biography in al-Kabir 1/2/132. See also 1892, 2057, 2350, 2351, 2392, 3089.