As a Go programmer, I find it quite puzzling that Rust didn't handle panic edge cases as well as Go did with defer keyword. Defer executes at the end of a function, regardless of whether it returned or panic'd, so you can write safe mutex code just by doing something like:
mutex.Lock()
defer mutex.Unlock()
And if you need to unlock the mutex in one of multiple places, you can wrap it into a sync.Once.
There must be a reason Rust doesn't do something similar...
It does do something similar... and more. IIUC, when unwinding on panic Rust does unlock the mutex, but it also "poisons" it so that a subsequent attempt to lock will return an error. This is because on panic all the code protected by the mutex didn't get to run to completion, possibly leaving an inconsistent state. A poisoned mutex can be reset, though.
As a Go programmer, I find it quite puzzling that Rust didn't handle panic edge cases as well as Go did with defer keyword. Defer executes at the end of a function, regardless of whether it returned or panic'd, so you can write safe mutex code just by doing something like:
And if you need to unlock the mutex in one of multiple places, you can wrap it into a sync.Once.There must be a reason Rust doesn't do something similar...
It does do something similar... and more. IIUC, when unwinding on panic Rust does unlock the mutex, but it also "poisons" it so that a subsequent attempt to lock will return an error. This is because on panic all the code protected by the mutex didn't get to run to completion, possibly leaving an inconsistent state. A poisoned mutex can be reset, though.