Go: Design Patterns for Real-World Projects

Function panic and recovery

Earlier in the chapter, it was stated that Go does not have the traditional exception mechanism offered by other languages. Nevertheless, in Go, there is a way to abruptly exit an executing function known as function panic. Conversely, when a program is panicking, Go provides a way of recovering and regaining control of the execution flow.

Function panic

During execution, a function may panic because of any one of following:

• Explicitly calling the panic built-in function
• Using a source code package that panics due to an abnormal state
• Accessing a nil value or an out-of-bound array element
• Concurrency deadlock

When a function panics, it aborts and executes its deferred calls. Then its caller panics, causing a chain reaction ...