package panics

import "github.com/sourcegraph/conc/panics"

Index

Examples

Types

type Catcher 

type Catcher struct {
	// contains filtered or unexported fields
}

Catcher is used to catch panics. You can execute a function with Try, which will catch any spawned panic. Try can be called any number of times, from any number of goroutines. Once all calls to Try have completed, you can get the value of the first panic (if any) with Recovered(), or you can just propagate the panic (re-panic) with Repanic().

Example

Code: 

{
	var pc Catcher
	i := 0
	pc.Try(func() { i += 1 })
	pc.Try(func() { panic("abort!") })
	pc.Try(func() { i += 1 })

	rc := pc.Recovered()

	fmt.Println(i)
	fmt.Println(rc.Value.(string))
	// Output:
	// 2
	// abort!
}

Output:

2
abort!
Example (Callers)

Code: 

{
	var pc Catcher
	pc.Try(func() { panic("mayday!") })

	recovered := pc.Recovered()

	// For debugging, the pre-formatted recovered.Stack is easier to use than
	// rc.Callers. This is not used in the example because its output is
	// machine-specific.

	frames := runtime.CallersFrames(recovered.Callers)
	for {
		frame, more := frames.Next()

		fmt.Println(frame.Function)

		if !more {
			break
		}
	}
	// Output:
	// github.com/sourcegraph/conc/panics.(*Catcher).tryRecover
	// runtime.gopanic
	// github.com/sourcegraph/conc/panics.ExampleCatcher_callers.func1
	// github.com/sourcegraph/conc/panics.(*Catcher).Try
	// github.com/sourcegraph/conc/panics.ExampleCatcher_callers
	// testing.runExample
	// testing.runExamples
	// testing.(*M).Run
	// main.main
	// runtime.main
	// runtime.goexit
}

Output:

github.com/sourcegraph/conc/panics.(*Catcher).tryRecover
runtime.gopanic
github.com/sourcegraph/conc/panics.ExampleCatcher_callers.func1
github.com/sourcegraph/conc/panics.(*Catcher).Try
github.com/sourcegraph/conc/panics.ExampleCatcher_callers
testing.runExample
testing.runExamples
testing.(*M).Run
main.main
runtime.main
runtime.goexit

func (*Catcher) Recovered 

func (p *Catcher) Recovered() *RecoveredPanic

Recovered returns the value of the first panic caught by Try, or nil if no calls to Try panicked.

func (*Catcher) Repanic 

func (p *Catcher) Repanic()

Repanic panics if any calls to Try caught a panic. It will panic with the value of the first panic caught, wrapped in a RecoveredPanic with caller information.

func (*Catcher) Try 

func (p *Catcher) Try(f func())

Try executes f, catching any panic it might spawn. It is safe to call from multiple goroutines simultaneously.

type RecoveredPanic 

type RecoveredPanic struct {
	// The original value of the panic.
	Value any
	// The caller list as returned by runtime.Callers when the panic was
	// recovered. Can be used to produce a more detailed stack information with
	// runtime.CallersFrames.
	Callers []uintptr
	// The formatted stacktrace from the goroutine where the panic was recovered.
	// Easier to use than Callers.
	Stack []byte
}

RecoveredPanic is a panic that was caught with recover().

func NewRecoveredPanic 

func NewRecoveredPanic(skip int, value any) RecoveredPanic

NewRecoveredPanic creates a RecoveredPanic from a panic value and a collected stacktrace. The skip parameter allows the caller to skip stack frames when collecting the stacktrace. Calling with a skip of 0 means include the call to NewRecoveredPanic in the stacktrace.

func (*RecoveredPanic) Error 

func (c *RecoveredPanic) Error() string

func (*RecoveredPanic) Unwrap 

func (c *RecoveredPanic) Unwrap() error

Source Files

panics.go

Version
v0.2.0
Published
Jan 17, 2023
Platform
js/wasm
Imports
4 packages
Last checked
2 minutes ago –

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