Go中的地图不具有线程安全性意味着什么？

Question

I want to know exactly what could happen when go maps accessed by multiple goroutins lets assume we have a map[int]*User. can modifying fields of User structure by multiple goroutins cause data corruption ? or just operations like len() are not thread safe what would be different if map was thread safe in Go ?

Answer 1

Concurrently modifying the *User could cause corruption regardless of the map. Reading the pointer from the map concurrently is safe, as long as there are no modifications to the map. Modifying the data *User points to makes no changes to the map itself.

Concurrently modifying the map[int]*User itself also risks data corruption.

There are no benign data races, always test your code with the race detector.