bug

Documentation

Overview

Package bug provides an interface for handling bugs.

A bug is a condition that should never happen. If a bug is encountered, the program should respond in an appropriate way. For example, if a bug is encountered in a web server, the server should return a 500 Internal Server Error response. If a bug is encountered in a command-line program, the program should exit with a non-zero exit code.

To handle a bug, call bug.Bug with a message. To format the message, use bug.Bugf.

Example:

// Override the handler to log the message and exit.
bug.SetHandler(func(message string) {
  log.Print(message)
  os.Exit(1)
})
// Handle a bug with Bug.
bug.Bug("this should never happen")
// Handle a bug with Bugf.
bug.Bugf("this should never happen: %s", "foo")

The default behavior of bug.Bug is to panic. Applications can and should change the behavior of bug.Bug by calling bug.SetHandler. The bug handler might be called from multiple goroutines, so it must be thread-safe. Library code should not call bug.SetHandler.

When calling bug.Bug from library code, always do so within a defer statement (unless it is being called from an infinite loop). This avoids making assumptions about the behavior of the handler (in particular, whether it returns or not).

Index

• func Bug(message string)
• func Bugf(format string, args ...interface{})
• func Handler() func(string)
• func SetHandler(h func(string))

Functions

func Bug

func Bug(message string)

Bug calls the bug handler with the given message. The default handler panics. The handler can be changed with bug.SetHandler.

When calling bug.Bug from library code, always do so within a defer statement. This avoids making assumptions about the behavior of the handler (in particular, whether it returns or not).

func Bugf

func Bugf(format string, args ...interface{})

Bugf calls the bug handler with the given formatted message. The default handler panics. The handler can be changed with bug.SetHandler.

When calling bug.Bugf from library code, always do so within a defer statement. This prevents making assumptions about the behavior of the handler (in particular, whether it returns or not).

func Handler

func Handler() func(string)

Handler returns the bug handler.

func SetHandler

func SetHandler(h func(string))

SetHandler sets the bug handler.

The bug handler might be called from multiple goroutines, so it must be thread-safe.

Library code should never call bug.SetHandler. It should only be called by application code. Furthermore, library code should never assume any particular behavior of the handler (in particular, whether it returns or not).