Go Channels Deep Dive

Core concept: Channels are typed pipes that allow goroutines to synchronize and pass values (“share memory by communicating”) instead of using locks/mutexes.
Unbuffered Channels (make(chan int)): Capacity is 0. Sends and receives block until the other side is ready, creating a direct handoff. If all goroutines block, the program deadlocks.
Buffered Channels (make(chan int, cap)): Sends only block when the buffer is full, receives only block when the buffer is empty.
Closing Channels (close(ch)):
- Signals no more data will be sent
- Sending to or double-closing a closed channel causes a panic
- Receiving from a closed channel drains any remaining buffered values, then yields the zero value. Use val, ok := <-ch to check if it’s closed (ok == false)
Directional Channels: You can restrict channels to send-only (chan<-) or receive-only (<-chan) in function signatures for compile-time safety.
Nil Channels: An uninitialized channel (nil) blocks forever on send/receive and panics if closed. This is actually a feature used to safely disable specific cases in a select statement.