Repository: pkg/errors
Branch: master
Commit: 5dd12d0cfe7f
Files: 16
Total size: 53.2 KB
Directory structure:
gitextract_u9vo6na2/
├── .gitignore
├── .travis.yml
├── LICENSE
├── Makefile
├── README.md
├── appveyor.yml
├── bench_test.go
├── errors.go
├── errors_test.go
├── example_test.go
├── format_test.go
├── go113.go
├── go113_test.go
├── json_test.go
├── stack.go
└── stack_test.go
================================================
FILE CONTENTS
================================================
================================================
FILE: .gitignore
================================================
# Compiled Object files, Static and Dynamic libs (Shared Objects)
*.o
*.a
*.so
# Folders
_obj
_test
# Architecture specific extensions/prefixes
*.[568vq]
[568vq].out
*.cgo1.go
*.cgo2.c
_cgo_defun.c
_cgo_gotypes.go
_cgo_export.*
_testmain.go
*.exe
*.test
*.prof
================================================
FILE: .travis.yml
================================================
arch:
- amd64
language: go
go_import_path: github.com/pkg/errors
go:
- 1.14
- 1.15
- tip
script:
- make check
================================================
FILE: LICENSE
================================================
Copyright (c) 2015, Dave Cheney <dave@cheney.net>
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
================================================
FILE: Makefile
================================================
PKGS := github.com/pkg/errors
SRCDIRS := $(shell go list -f '{{.Dir}}' $(PKGS))
GO := go
check: test vet gofmt misspell unconvert staticcheck ineffassign unparam
test:
$(GO) test $(PKGS)
vet: | test
$(GO) vet $(PKGS)
staticcheck:
$(GO) get honnef.co/go/tools/cmd/staticcheck
staticcheck -checks all $(PKGS)
misspell:
$(GO) get github.com/client9/misspell/cmd/misspell
misspell \
-locale GB \
-error \
*.md *.go
unconvert:
$(GO) get github.com/mdempsky/unconvert
unconvert -v $(PKGS)
ineffassign:
$(GO) get github.com/gordonklaus/ineffassign
find $(SRCDIRS) -name '*.go' | xargs ineffassign
pedantic: check errcheck
unparam:
$(GO) get mvdan.cc/unparam
unparam ./...
errcheck:
$(GO) get github.com/kisielk/errcheck
errcheck $(PKGS)
gofmt:
@echo Checking code is gofmted
@test -z "$(shell gofmt -s -l -d -e $(SRCDIRS) | tee /dev/stderr)"
================================================
FILE: README.md
================================================
# errors [](https://travis-ci.org/pkg/errors) [](https://ci.appveyor.com/project/davecheney/errors/branch/master) [](http://godoc.org/github.com/pkg/errors) [](https://goreportcard.com/report/github.com/pkg/errors) [](https://sourcegraph.com/github.com/pkg/errors?badge)
Package errors provides simple error handling primitives.
`go get github.com/pkg/errors`
The traditional error handling idiom in Go is roughly akin to
```go
if err != nil {
return err
}
```
which applied recursively up the call stack results in error reports without context or debugging information. The errors package allows programmers to add context to the failure path in their code in a way that does not destroy the original value of the error.
## Adding context to an error
The errors.Wrap function returns a new error that adds context to the original error. For example
```go
_, err := ioutil.ReadAll(r)
if err != nil {
return errors.Wrap(err, "read failed")
}
```
## Retrieving the cause of an error
Using `errors.Wrap` constructs a stack of errors, adding context to the preceding error. Depending on the nature of the error it may be necessary to reverse the operation of errors.Wrap to retrieve the original error for inspection. Any error value which implements this interface can be inspected by `errors.Cause`.
```go
type causer interface {
Cause() error
}
```
`errors.Cause` will recursively retrieve the topmost error which does not implement `causer`, which is assumed to be the original cause. For example:
```go
switch err := errors.Cause(err).(type) {
case *MyError:
// handle specifically
default:
// unknown error
}
```
[Read the package documentation for more information](https://godoc.org/github.com/pkg/errors).
## Roadmap
With the upcoming [Go2 error proposals](https://go.googlesource.com/proposal/+/master/design/go2draft.md) this package is moving into maintenance mode. The roadmap for a 1.0 release is as follows:
- 0.9. Remove pre Go 1.9 and Go 1.10 support, address outstanding pull requests (if possible)
- 1.0. Final release.
## Contributing
Because of the Go2 errors changes, this package is not accepting proposals for new functionality. With that said, we welcome pull requests, bug fixes and issue reports.
Before sending a PR, please discuss your change by raising an issue.
## License
BSD-2-Clause
================================================
FILE: appveyor.yml
================================================
version: build-{build}.{branch}
clone_folder: C:\gopath\src\github.com\pkg\errors
shallow_clone: true # for startup speed
environment:
GOPATH: C:\gopath
platform:
- x64
# http://www.appveyor.com/docs/installed-software
install:
# some helpful output for debugging builds
- go version
- go env
# pre-installed MinGW at C:\MinGW is 32bit only
# but MSYS2 at C:\msys64 has mingw64
- set PATH=C:\msys64\mingw64\bin;%PATH%
- gcc --version
- g++ --version
build_script:
- go install -v ./...
test_script:
- set PATH=C:\gopath\bin;%PATH%
- go test -v ./...
#artifacts:
# - path: '%GOPATH%\bin\*.exe'
deploy: off
================================================
FILE: bench_test.go
================================================
// +build go1.7
package errors
import (
"fmt"
"testing"
stderrors "errors"
)
func noErrors(at, depth int) error {
if at >= depth {
return stderrors.New("no error")
}
return noErrors(at+1, depth)
}
func yesErrors(at, depth int) error {
if at >= depth {
return New("ye error")
}
return yesErrors(at+1, depth)
}
// GlobalE is an exported global to store the result of benchmark results,
// preventing the compiler from optimising the benchmark functions away.
var GlobalE interface{}
func BenchmarkErrors(b *testing.B) {
type run struct {
stack int
std bool
}
runs := []run{
{10, false},
{10, true},
{100, false},
{100, true},
{1000, false},
{1000, true},
}
for _, r := range runs {
part := "pkg/errors"
if r.std {
part = "errors"
}
name := fmt.Sprintf("%s-stack-%d", part, r.stack)
b.Run(name, func(b *testing.B) {
var err error
f := yesErrors
if r.std {
f = noErrors
}
b.ReportAllocs()
for i := 0; i < b.N; i++ {
err = f(0, r.stack)
}
b.StopTimer()
GlobalE = err
})
}
}
func BenchmarkStackFormatting(b *testing.B) {
type run struct {
stack int
format string
}
runs := []run{
{10, "%s"},
{10, "%v"},
{10, "%+v"},
{30, "%s"},
{30, "%v"},
{30, "%+v"},
{60, "%s"},
{60, "%v"},
{60, "%+v"},
}
var stackStr string
for _, r := range runs {
name := fmt.Sprintf("%s-stack-%d", r.format, r.stack)
b.Run(name, func(b *testing.B) {
err := yesErrors(0, r.stack)
b.ReportAllocs()
b.ResetTimer()
for i := 0; i < b.N; i++ {
stackStr = fmt.Sprintf(r.format, err)
}
b.StopTimer()
})
}
for _, r := range runs {
name := fmt.Sprintf("%s-stacktrace-%d", r.format, r.stack)
b.Run(name, func(b *testing.B) {
err := yesErrors(0, r.stack)
st := err.(*fundamental).stack.StackTrace()
b.ReportAllocs()
b.ResetTimer()
for i := 0; i < b.N; i++ {
stackStr = fmt.Sprintf(r.format, st)
}
b.StopTimer()
})
}
GlobalE = stackStr
}
================================================
FILE: errors.go
================================================
// Package errors provides simple error handling primitives.
//
// The traditional error handling idiom in Go is roughly akin to
//
// if err != nil {
// return err
// }
//
// which when applied recursively up the call stack results in error reports
// without context or debugging information. The errors package allows
// programmers to add context to the failure path in their code in a way
// that does not destroy the original value of the error.
//
// Adding context to an error
//
// The errors.Wrap function returns a new error that adds context to the
// original error by recording a stack trace at the point Wrap is called,
// together with the supplied message. For example
//
// _, err := ioutil.ReadAll(r)
// if err != nil {
// return errors.Wrap(err, "read failed")
// }
//
// If additional control is required, the errors.WithStack and
// errors.WithMessage functions destructure errors.Wrap into its component
// operations: annotating an error with a stack trace and with a message,
// respectively.
//
// Retrieving the cause of an error
//
// Using errors.Wrap constructs a stack of errors, adding context to the
// preceding error. Depending on the nature of the error it may be necessary
// to reverse the operation of errors.Wrap to retrieve the original error
// for inspection. Any error value which implements this interface
//
// type causer interface {
// Cause() error
// }
//
// can be inspected by errors.Cause. errors.Cause will recursively retrieve
// the topmost error that does not implement causer, which is assumed to be
// the original cause. For example:
//
// switch err := errors.Cause(err).(type) {
// case *MyError:
// // handle specifically
// default:
// // unknown error
// }
//
// Although the causer interface is not exported by this package, it is
// considered a part of its stable public interface.
//
// Formatted printing of errors
//
// All error values returned from this package implement fmt.Formatter and can
// be formatted by the fmt package. The following verbs are supported:
//
// %s print the error. If the error has a Cause it will be
// printed recursively.
// %v see %s
// %+v extended format. Each Frame of the error's StackTrace will
// be printed in detail.
//
// Retrieving the stack trace of an error or wrapper
//
// New, Errorf, Wrap, and Wrapf record a stack trace at the point they are
// invoked. This information can be retrieved with the following interface:
//
// type stackTracer interface {
// StackTrace() errors.StackTrace
// }
//
// The returned errors.StackTrace type is defined as
//
// type StackTrace []Frame
//
// The Frame type represents a call site in the stack trace. Frame supports
// the fmt.Formatter interface that can be used for printing information about
// the stack trace of this error. For example:
//
// if err, ok := err.(stackTracer); ok {
// for _, f := range err.StackTrace() {
// fmt.Printf("%+s:%d\n", f, f)
// }
// }
//
// Although the stackTracer interface is not exported by this package, it is
// considered a part of its stable public interface.
//
// See the documentation for Frame.Format for more details.
package errors
import (
"fmt"
"io"
)
// New returns an error with the supplied message.
// New also records the stack trace at the point it was called.
func New(message string) error {
return &fundamental{
msg: message,
stack: callers(),
}
}
// Errorf formats according to a format specifier and returns the string
// as a value that satisfies error.
// Errorf also records the stack trace at the point it was called.
func Errorf(format string, args ...interface{}) error {
return &fundamental{
msg: fmt.Sprintf(format, args...),
stack: callers(),
}
}
// fundamental is an error that has a message and a stack, but no caller.
type fundamental struct {
msg string
*stack
}
func (f *fundamental) Error() string { return f.msg }
func (f *fundamental) Format(s fmt.State, verb rune) {
switch verb {
case 'v':
if s.Flag('+') {
io.WriteString(s, f.msg)
f.stack.Format(s, verb)
return
}
fallthrough
case 's':
io.WriteString(s, f.msg)
case 'q':
fmt.Fprintf(s, "%q", f.msg)
}
}
// WithStack annotates err with a stack trace at the point WithStack was called.
// If err is nil, WithStack returns nil.
func WithStack(err error) error {
if err == nil {
return nil
}
return &withStack{
err,
callers(),
}
}
type withStack struct {
error
*stack
}
func (w *withStack) Cause() error { return w.error }
// Unwrap provides compatibility for Go 1.13 error chains.
func (w *withStack) Unwrap() error { return w.error }
func (w *withStack) Format(s fmt.State, verb rune) {
switch verb {
case 'v':
if s.Flag('+') {
fmt.Fprintf(s, "%+v", w.Cause())
w.stack.Format(s, verb)
return
}
fallthrough
case 's':
io.WriteString(s, w.Error())
case 'q':
fmt.Fprintf(s, "%q", w.Error())
}
}
// Wrap returns an error annotating err with a stack trace
// at the point Wrap is called, and the supplied message.
// If err is nil, Wrap returns nil.
func Wrap(err error, message string) error {
if err == nil {
return nil
}
err = &withMessage{
cause: err,
msg: message,
}
return &withStack{
err,
callers(),
}
}
// Wrapf returns an error annotating err with a stack trace
// at the point Wrapf is called, and the format specifier.
// If err is nil, Wrapf returns nil.
func Wrapf(err error, format string, args ...interface{}) error {
if err == nil {
return nil
}
err = &withMessage{
cause: err,
msg: fmt.Sprintf(format, args...),
}
return &withStack{
err,
callers(),
}
}
// WithMessage annotates err with a new message.
// If err is nil, WithMessage returns nil.
func WithMessage(err error, message string) error {
if err == nil {
return nil
}
return &withMessage{
cause: err,
msg: message,
}
}
// WithMessagef annotates err with the format specifier.
// If err is nil, WithMessagef returns nil.
func WithMessagef(err error, format string, args ...interface{}) error {
if err == nil {
return nil
}
return &withMessage{
cause: err,
msg: fmt.Sprintf(format, args...),
}
}
type withMessage struct {
cause error
msg string
}
func (w *withMessage) Error() string { return w.msg + ": " + w.cause.Error() }
func (w *withMessage) Cause() error { return w.cause }
// Unwrap provides compatibility for Go 1.13 error chains.
func (w *withMessage) Unwrap() error { return w.cause }
func (w *withMessage) Format(s fmt.State, verb rune) {
switch verb {
case 'v':
if s.Flag('+') {
fmt.Fprintf(s, "%+v\n", w.Cause())
io.WriteString(s, w.msg)
return
}
fallthrough
case 's', 'q':
io.WriteString(s, w.Error())
}
}
// Cause returns the underlying cause of the error, if possible.
// An error value has a cause if it implements the following
// interface:
//
// type causer interface {
// Cause() error
// }
//
// If the error does not implement Cause, the original error will
// be returned. If the error is nil, nil will be returned without further
// investigation.
func Cause(err error) error {
type causer interface {
Cause() error
}
for err != nil {
cause, ok := err.(causer)
if !ok {
break
}
err = cause.Cause()
}
return err
}
================================================
FILE: errors_test.go
================================================
package errors
import (
"errors"
"fmt"
"io"
"reflect"
"testing"
)
func TestNew(t *testing.T) {
tests := []struct {
err string
want error
}{
{"", fmt.Errorf("")},
{"foo", fmt.Errorf("foo")},
{"foo", New("foo")},
{"string with format specifiers: %v", errors.New("string with format specifiers: %v")},
}
for _, tt := range tests {
got := New(tt.err)
if got.Error() != tt.want.Error() {
t.Errorf("New.Error(): got: %q, want %q", got, tt.want)
}
}
}
func TestWrapNil(t *testing.T) {
got := Wrap(nil, "no error")
if got != nil {
t.Errorf("Wrap(nil, \"no error\"): got %#v, expected nil", got)
}
}
func TestWrap(t *testing.T) {
tests := []struct {
err error
message string
want string
}{
{io.EOF, "read error", "read error: EOF"},
{Wrap(io.EOF, "read error"), "client error", "client error: read error: EOF"},
}
for _, tt := range tests {
got := Wrap(tt.err, tt.message).Error()
if got != tt.want {
t.Errorf("Wrap(%v, %q): got: %v, want %v", tt.err, tt.message, got, tt.want)
}
}
}
type nilError struct{}
func (nilError) Error() string { return "nil error" }
func TestCause(t *testing.T) {
x := New("error")
tests := []struct {
err error
want error
}{{
// nil error is nil
err: nil,
want: nil,
}, {
// explicit nil error is nil
err: (error)(nil),
want: nil,
}, {
// typed nil is nil
err: (*nilError)(nil),
want: (*nilError)(nil),
}, {
// uncaused error is unaffected
err: io.EOF,
want: io.EOF,
}, {
// caused error returns cause
err: Wrap(io.EOF, "ignored"),
want: io.EOF,
}, {
err: x, // return from errors.New
want: x,
}, {
WithMessage(nil, "whoops"),
nil,
}, {
WithMessage(io.EOF, "whoops"),
io.EOF,
}, {
WithStack(nil),
nil,
}, {
WithStack(io.EOF),
io.EOF,
}}
for i, tt := range tests {
got := Cause(tt.err)
if !reflect.DeepEqual(got, tt.want) {
t.Errorf("test %d: got %#v, want %#v", i+1, got, tt.want)
}
}
}
func TestWrapfNil(t *testing.T) {
got := Wrapf(nil, "no error")
if got != nil {
t.Errorf("Wrapf(nil, \"no error\"): got %#v, expected nil", got)
}
}
func TestWrapf(t *testing.T) {
tests := []struct {
err error
message string
want string
}{
{io.EOF, "read error", "read error: EOF"},
{Wrapf(io.EOF, "read error without format specifiers"), "client error", "client error: read error without format specifiers: EOF"},
{Wrapf(io.EOF, "read error with %d format specifier", 1), "client error", "client error: read error with 1 format specifier: EOF"},
}
for _, tt := range tests {
got := Wrapf(tt.err, tt.message).Error()
if got != tt.want {
t.Errorf("Wrapf(%v, %q): got: %v, want %v", tt.err, tt.message, got, tt.want)
}
}
}
func TestErrorf(t *testing.T) {
tests := []struct {
err error
want string
}{
{Errorf("read error without format specifiers"), "read error without format specifiers"},
{Errorf("read error with %d format specifier", 1), "read error with 1 format specifier"},
}
for _, tt := range tests {
got := tt.err.Error()
if got != tt.want {
t.Errorf("Errorf(%v): got: %q, want %q", tt.err, got, tt.want)
}
}
}
func TestWithStackNil(t *testing.T) {
got := WithStack(nil)
if got != nil {
t.Errorf("WithStack(nil): got %#v, expected nil", got)
}
}
func TestWithStack(t *testing.T) {
tests := []struct {
err error
want string
}{
{io.EOF, "EOF"},
{WithStack(io.EOF), "EOF"},
}
for _, tt := range tests {
got := WithStack(tt.err).Error()
if got != tt.want {
t.Errorf("WithStack(%v): got: %v, want %v", tt.err, got, tt.want)
}
}
}
func TestWithMessageNil(t *testing.T) {
got := WithMessage(nil, "no error")
if got != nil {
t.Errorf("WithMessage(nil, \"no error\"): got %#v, expected nil", got)
}
}
func TestWithMessage(t *testing.T) {
tests := []struct {
err error
message string
want string
}{
{io.EOF, "read error", "read error: EOF"},
{WithMessage(io.EOF, "read error"), "client error", "client error: read error: EOF"},
}
for _, tt := range tests {
got := WithMessage(tt.err, tt.message).Error()
if got != tt.want {
t.Errorf("WithMessage(%v, %q): got: %q, want %q", tt.err, tt.message, got, tt.want)
}
}
}
func TestWithMessagefNil(t *testing.T) {
got := WithMessagef(nil, "no error")
if got != nil {
t.Errorf("WithMessage(nil, \"no error\"): got %#v, expected nil", got)
}
}
func TestWithMessagef(t *testing.T) {
tests := []struct {
err error
message string
want string
}{
{io.EOF, "read error", "read error: EOF"},
{WithMessagef(io.EOF, "read error without format specifier"), "client error", "client error: read error without format specifier: EOF"},
{WithMessagef(io.EOF, "read error with %d format specifier", 1), "client error", "client error: read error with 1 format specifier: EOF"},
}
for _, tt := range tests {
got := WithMessagef(tt.err, tt.message).Error()
if got != tt.want {
t.Errorf("WithMessage(%v, %q): got: %q, want %q", tt.err, tt.message, got, tt.want)
}
}
}
// errors.New, etc values are not expected to be compared by value
// but the change in errors#27 made them incomparable. Assert that
// various kinds of errors have a functional equality operator, even
// if the result of that equality is always false.
func TestErrorEquality(t *testing.T) {
vals := []error{
nil,
io.EOF,
errors.New("EOF"),
New("EOF"),
Errorf("EOF"),
Wrap(io.EOF, "EOF"),
Wrapf(io.EOF, "EOF%d", 2),
WithMessage(nil, "whoops"),
WithMessage(io.EOF, "whoops"),
WithStack(io.EOF),
WithStack(nil),
}
for i := range vals {
for j := range vals {
_ = vals[i] == vals[j] // mustn't panic
}
}
}
================================================
FILE: example_test.go
================================================
package errors_test
import (
"fmt"
"github.com/pkg/errors"
)
func ExampleNew() {
err := errors.New("whoops")
fmt.Println(err)
// Output: whoops
}
func ExampleNew_printf() {
err := errors.New("whoops")
fmt.Printf("%+v", err)
// Example output:
// whoops
// github.com/pkg/errors_test.ExampleNew_printf
// /home/dfc/src/github.com/pkg/errors/example_test.go:17
// testing.runExample
// /home/dfc/go/src/testing/example.go:114
// testing.RunExamples
// /home/dfc/go/src/testing/example.go:38
// testing.(*M).Run
// /home/dfc/go/src/testing/testing.go:744
// main.main
// /github.com/pkg/errors/_test/_testmain.go:106
// runtime.main
// /home/dfc/go/src/runtime/proc.go:183
// runtime.goexit
// /home/dfc/go/src/runtime/asm_amd64.s:2059
}
func ExampleWithMessage() {
cause := errors.New("whoops")
err := errors.WithMessage(cause, "oh noes")
fmt.Println(err)
// Output: oh noes: whoops
}
func ExampleWithStack() {
cause := errors.New("whoops")
err := errors.WithStack(cause)
fmt.Println(err)
// Output: whoops
}
func ExampleWithStack_printf() {
cause := errors.New("whoops")
err := errors.WithStack(cause)
fmt.Printf("%+v", err)
// Example Output:
// whoops
// github.com/pkg/errors_test.ExampleWithStack_printf
// /home/fabstu/go/src/github.com/pkg/errors/example_test.go:55
// testing.runExample
// /usr/lib/go/src/testing/example.go:114
// testing.RunExamples
// /usr/lib/go/src/testing/example.go:38
// testing.(*M).Run
// /usr/lib/go/src/testing/testing.go:744
// main.main
// github.com/pkg/errors/_test/_testmain.go:106
// runtime.main
// /usr/lib/go/src/runtime/proc.go:183
// runtime.goexit
// /usr/lib/go/src/runtime/asm_amd64.s:2086
// github.com/pkg/errors_test.ExampleWithStack_printf
// /home/fabstu/go/src/github.com/pkg/errors/example_test.go:56
// testing.runExample
// /usr/lib/go/src/testing/example.go:114
// testing.RunExamples
// /usr/lib/go/src/testing/example.go:38
// testing.(*M).Run
// /usr/lib/go/src/testing/testing.go:744
// main.main
// github.com/pkg/errors/_test/_testmain.go:106
// runtime.main
// /usr/lib/go/src/runtime/proc.go:183
// runtime.goexit
// /usr/lib/go/src/runtime/asm_amd64.s:2086
}
func ExampleWrap() {
cause := errors.New("whoops")
err := errors.Wrap(cause, "oh noes")
fmt.Println(err)
// Output: oh noes: whoops
}
func fn() error {
e1 := errors.New("error")
e2 := errors.Wrap(e1, "inner")
e3 := errors.Wrap(e2, "middle")
return errors.Wrap(e3, "outer")
}
func ExampleCause() {
err := fn()
fmt.Println(err)
fmt.Println(errors.Cause(err))
// Output: outer: middle: inner: error
// error
}
func ExampleWrap_extended() {
err := fn()
fmt.Printf("%+v\n", err)
// Example output:
// error
// github.com/pkg/errors_test.fn
// /home/dfc/src/github.com/pkg/errors/example_test.go:47
// github.com/pkg/errors_test.ExampleCause_printf
// /home/dfc/src/github.com/pkg/errors/example_test.go:63
// testing.runExample
// /home/dfc/go/src/testing/example.go:114
// testing.RunExamples
// /home/dfc/go/src/testing/example.go:38
// testing.(*M).Run
// /home/dfc/go/src/testing/testing.go:744
// main.main
// /github.com/pkg/errors/_test/_testmain.go:104
// runtime.main
// /home/dfc/go/src/runtime/proc.go:183
// runtime.goexit
// /home/dfc/go/src/runtime/asm_amd64.s:2059
// github.com/pkg/errors_test.fn
// /home/dfc/src/github.com/pkg/errors/example_test.go:48: inner
// github.com/pkg/errors_test.fn
// /home/dfc/src/github.com/pkg/errors/example_test.go:49: middle
// github.com/pkg/errors_test.fn
// /home/dfc/src/github.com/pkg/errors/example_test.go:50: outer
}
func ExampleWrapf() {
cause := errors.New("whoops")
err := errors.Wrapf(cause, "oh noes #%d", 2)
fmt.Println(err)
// Output: oh noes #2: whoops
}
func ExampleErrorf_extended() {
err := errors.Errorf("whoops: %s", "foo")
fmt.Printf("%+v", err)
// Example output:
// whoops: foo
// github.com/pkg/errors_test.ExampleErrorf
// /home/dfc/src/github.com/pkg/errors/example_test.go:101
// testing.runExample
// /home/dfc/go/src/testing/example.go:114
// testing.RunExamples
// /home/dfc/go/src/testing/example.go:38
// testing.(*M).Run
// /home/dfc/go/src/testing/testing.go:744
// main.main
// /github.com/pkg/errors/_test/_testmain.go:102
// runtime.main
// /home/dfc/go/src/runtime/proc.go:183
// runtime.goexit
// /home/dfc/go/src/runtime/asm_amd64.s:2059
}
func Example_stackTrace() {
type stackTracer interface {
StackTrace() errors.StackTrace
}
err, ok := errors.Cause(fn()).(stackTracer)
if !ok {
panic("oops, err does not implement stackTracer")
}
st := err.StackTrace()
fmt.Printf("%+v", st[0:2]) // top two frames
// Example output:
// github.com/pkg/errors_test.fn
// /home/dfc/src/github.com/pkg/errors/example_test.go:47
// github.com/pkg/errors_test.Example_stackTrace
// /home/dfc/src/github.com/pkg/errors/example_test.go:127
}
func ExampleCause_printf() {
err := errors.Wrap(func() error {
return func() error {
return errors.New("hello world")
}()
}(), "failed")
fmt.Printf("%v", err)
// Output: failed: hello world
}
================================================
FILE: format_test.go
================================================
package errors
import (
"errors"
"fmt"
"io"
"regexp"
"strings"
"testing"
)
func TestFormatNew(t *testing.T) {
tests := []struct {
error
format string
want string
}{{
New("error"),
"%s",
"error",
}, {
New("error"),
"%v",
"error",
}, {
New("error"),
"%+v",
"error\n" +
"github.com/pkg/errors.TestFormatNew\n" +
"\t.+/github.com/pkg/errors/format_test.go:26",
}, {
New("error"),
"%q",
`"error"`,
}}
for i, tt := range tests {
testFormatRegexp(t, i, tt.error, tt.format, tt.want)
}
}
func TestFormatErrorf(t *testing.T) {
tests := []struct {
error
format string
want string
}{{
Errorf("%s", "error"),
"%s",
"error",
}, {
Errorf("%s", "error"),
"%v",
"error",
}, {
Errorf("%s", "error"),
"%+v",
"error\n" +
"github.com/pkg/errors.TestFormatErrorf\n" +
"\t.+/github.com/pkg/errors/format_test.go:56",
}}
for i, tt := range tests {
testFormatRegexp(t, i, tt.error, tt.format, tt.want)
}
}
func TestFormatWrap(t *testing.T) {
tests := []struct {
error
format string
want string
}{{
Wrap(New("error"), "error2"),
"%s",
"error2: error",
}, {
Wrap(New("error"), "error2"),
"%v",
"error2: error",
}, {
Wrap(New("error"), "error2"),
"%+v",
"error\n" +
"github.com/pkg/errors.TestFormatWrap\n" +
"\t.+/github.com/pkg/errors/format_test.go:82",
}, {
Wrap(io.EOF, "error"),
"%s",
"error: EOF",
}, {
Wrap(io.EOF, "error"),
"%v",
"error: EOF",
}, {
Wrap(io.EOF, "error"),
"%+v",
"EOF\n" +
"error\n" +
"github.com/pkg/errors.TestFormatWrap\n" +
"\t.+/github.com/pkg/errors/format_test.go:96",
}, {
Wrap(Wrap(io.EOF, "error1"), "error2"),
"%+v",
"EOF\n" +
"error1\n" +
"github.com/pkg/errors.TestFormatWrap\n" +
"\t.+/github.com/pkg/errors/format_test.go:103\n",
}, {
Wrap(New("error with space"), "context"),
"%q",
`"context: error with space"`,
}}
for i, tt := range tests {
testFormatRegexp(t, i, tt.error, tt.format, tt.want)
}
}
func TestFormatWrapf(t *testing.T) {
tests := []struct {
error
format string
want string
}{{
Wrapf(io.EOF, "error%d", 2),
"%s",
"error2: EOF",
}, {
Wrapf(io.EOF, "error%d", 2),
"%v",
"error2: EOF",
}, {
Wrapf(io.EOF, "error%d", 2),
"%+v",
"EOF\n" +
"error2\n" +
"github.com/pkg/errors.TestFormatWrapf\n" +
"\t.+/github.com/pkg/errors/format_test.go:134",
}, {
Wrapf(New("error"), "error%d", 2),
"%s",
"error2: error",
}, {
Wrapf(New("error"), "error%d", 2),
"%v",
"error2: error",
}, {
Wrapf(New("error"), "error%d", 2),
"%+v",
"error\n" +
"github.com/pkg/errors.TestFormatWrapf\n" +
"\t.+/github.com/pkg/errors/format_test.go:149",
}}
for i, tt := range tests {
testFormatRegexp(t, i, tt.error, tt.format, tt.want)
}
}
func TestFormatWithStack(t *testing.T) {
tests := []struct {
error
format string
want []string
}{{
WithStack(io.EOF),
"%s",
[]string{"EOF"},
}, {
WithStack(io.EOF),
"%v",
[]string{"EOF"},
}, {
WithStack(io.EOF),
"%+v",
[]string{"EOF",
"github.com/pkg/errors.TestFormatWithStack\n" +
"\t.+/github.com/pkg/errors/format_test.go:175"},
}, {
WithStack(New("error")),
"%s",
[]string{"error"},
}, {
WithStack(New("error")),
"%v",
[]string{"error"},
}, {
WithStack(New("error")),
"%+v",
[]string{"error",
"github.com/pkg/errors.TestFormatWithStack\n" +
"\t.+/github.com/pkg/errors/format_test.go:189",
"github.com/pkg/errors.TestFormatWithStack\n" +
"\t.+/github.com/pkg/errors/format_test.go:189"},
}, {
WithStack(WithStack(io.EOF)),
"%+v",
[]string{"EOF",
"github.com/pkg/errors.TestFormatWithStack\n" +
"\t.+/github.com/pkg/errors/format_test.go:197",
"github.com/pkg/errors.TestFormatWithStack\n" +
"\t.+/github.com/pkg/errors/format_test.go:197"},
}, {
WithStack(WithStack(Wrapf(io.EOF, "message"))),
"%+v",
[]string{"EOF",
"message",
"github.com/pkg/errors.TestFormatWithStack\n" +
"\t.+/github.com/pkg/errors/format_test.go:205",
"github.com/pkg/errors.TestFormatWithStack\n" +
"\t.+/github.com/pkg/errors/format_test.go:205",
"github.com/pkg/errors.TestFormatWithStack\n" +
"\t.+/github.com/pkg/errors/format_test.go:205"},
}, {
WithStack(Errorf("error%d", 1)),
"%+v",
[]string{"error1",
"github.com/pkg/errors.TestFormatWithStack\n" +
"\t.+/github.com/pkg/errors/format_test.go:216",
"github.com/pkg/errors.TestFormatWithStack\n" +
"\t.+/github.com/pkg/errors/format_test.go:216"},
}}
for i, tt := range tests {
testFormatCompleteCompare(t, i, tt.error, tt.format, tt.want, true)
}
}
func TestFormatWithMessage(t *testing.T) {
tests := []struct {
error
format string
want []string
}{{
WithMessage(New("error"), "error2"),
"%s",
[]string{"error2: error"},
}, {
WithMessage(New("error"), "error2"),
"%v",
[]string{"error2: error"},
}, {
WithMessage(New("error"), "error2"),
"%+v",
[]string{
"error",
"github.com/pkg/errors.TestFormatWithMessage\n" +
"\t.+/github.com/pkg/errors/format_test.go:244",
"error2"},
}, {
WithMessage(io.EOF, "addition1"),
"%s",
[]string{"addition1: EOF"},
}, {
WithMessage(io.EOF, "addition1"),
"%v",
[]string{"addition1: EOF"},
}, {
WithMessage(io.EOF, "addition1"),
"%+v",
[]string{"EOF", "addition1"},
}, {
WithMessage(WithMessage(io.EOF, "addition1"), "addition2"),
"%v",
[]string{"addition2: addition1: EOF"},
}, {
WithMessage(WithMessage(io.EOF, "addition1"), "addition2"),
"%+v",
[]string{"EOF", "addition1", "addition2"},
}, {
Wrap(WithMessage(io.EOF, "error1"), "error2"),
"%+v",
[]string{"EOF", "error1", "error2",
"github.com/pkg/errors.TestFormatWithMessage\n" +
"\t.+/github.com/pkg/errors/format_test.go:272"},
}, {
WithMessage(Errorf("error%d", 1), "error2"),
"%+v",
[]string{"error1",
"github.com/pkg/errors.TestFormatWithMessage\n" +
"\t.+/github.com/pkg/errors/format_test.go:278",
"error2"},
}, {
WithMessage(WithStack(io.EOF), "error"),
"%+v",
[]string{
"EOF",
"github.com/pkg/errors.TestFormatWithMessage\n" +
"\t.+/github.com/pkg/errors/format_test.go:285",
"error"},
}, {
WithMessage(Wrap(WithStack(io.EOF), "inside-error"), "outside-error"),
"%+v",
[]string{
"EOF",
"github.com/pkg/errors.TestFormatWithMessage\n" +
"\t.+/github.com/pkg/errors/format_test.go:293",
"inside-error",
"github.com/pkg/errors.TestFormatWithMessage\n" +
"\t.+/github.com/pkg/errors/format_test.go:293",
"outside-error"},
}}
for i, tt := range tests {
testFormatCompleteCompare(t, i, tt.error, tt.format, tt.want, true)
}
}
func TestFormatGeneric(t *testing.T) {
starts := []struct {
err error
want []string
}{
{New("new-error"), []string{
"new-error",
"github.com/pkg/errors.TestFormatGeneric\n" +
"\t.+/github.com/pkg/errors/format_test.go:315"},
}, {Errorf("errorf-error"), []string{
"errorf-error",
"github.com/pkg/errors.TestFormatGeneric\n" +
"\t.+/github.com/pkg/errors/format_test.go:319"},
}, {errors.New("errors-new-error"), []string{
"errors-new-error"},
},
}
wrappers := []wrapper{
{
func(err error) error { return WithMessage(err, "with-message") },
[]string{"with-message"},
}, {
func(err error) error { return WithStack(err) },
[]string{
"github.com/pkg/errors.(func·002|TestFormatGeneric.func2)\n\t" +
".+/github.com/pkg/errors/format_test.go:333",
},
}, {
func(err error) error { return Wrap(err, "wrap-error") },
[]string{
"wrap-error",
"github.com/pkg/errors.(func·003|TestFormatGeneric.func3)\n\t" +
".+/github.com/pkg/errors/format_test.go:339",
},
}, {
func(err error) error { return Wrapf(err, "wrapf-error%d", 1) },
[]string{
"wrapf-error1",
"github.com/pkg/errors.(func·004|TestFormatGeneric.func4)\n\t" +
".+/github.com/pkg/errors/format_test.go:346",
},
},
}
for s := range starts {
err := starts[s].err
want := starts[s].want
testFormatCompleteCompare(t, s, err, "%+v", want, false)
testGenericRecursive(t, err, want, wrappers, 3)
}
}
func wrappedNew(message string) error { // This function will be mid-stack inlined in go 1.12+
return New(message)
}
func TestFormatWrappedNew(t *testing.T) {
tests := []struct {
error
format string
want string
}{{
wrappedNew("error"),
"%+v",
"error\n" +
"github.com/pkg/errors.wrappedNew\n" +
"\t.+/github.com/pkg/errors/format_test.go:364\n" +
"github.com/pkg/errors.TestFormatWrappedNew\n" +
"\t.+/github.com/pkg/errors/format_test.go:373",
}}
for i, tt := range tests {
testFormatRegexp(t, i, tt.error, tt.format, tt.want)
}
}
func testFormatRegexp(t *testing.T, n int, arg interface{}, format, want string) {
t.Helper()
got := fmt.Sprintf(format, arg)
gotLines := strings.SplitN(got, "\n", -1)
wantLines := strings.SplitN(want, "\n", -1)
if len(wantLines) > len(gotLines) {
t.Errorf("test %d: wantLines(%d) > gotLines(%d):\n got: %q\nwant: %q", n+1, len(wantLines), len(gotLines), got, want)
return
}
for i, w := range wantLines {
match, err := regexp.MatchString(w, gotLines[i])
if err != nil {
t.Fatal(err)
}
if !match {
t.Errorf("test %d: line %d: fmt.Sprintf(%q, err):\n got: %q\nwant: %q", n+1, i+1, format, got, want)
}
}
}
var stackLineR = regexp.MustCompile(`\.`)
// parseBlocks parses input into a slice, where:
// - incase entry contains a newline, its a stacktrace
// - incase entry contains no newline, its a solo line.
//
// Detecting stack boundaries only works incase the WithStack-calls are
// to be found on the same line, thats why it is optionally here.
//
// Example use:
//
// for _, e := range blocks {
// if strings.ContainsAny(e, "\n") {
// // Match as stack
// } else {
// // Match as line
// }
// }
//
func parseBlocks(input string, detectStackboundaries bool) ([]string, error) {
var blocks []string
stack := ""
wasStack := false
lines := map[string]bool{} // already found lines
for _, l := range strings.Split(input, "\n") {
isStackLine := stackLineR.MatchString(l)
switch {
case !isStackLine && wasStack:
blocks = append(blocks, stack, l)
stack = ""
lines = map[string]bool{}
case isStackLine:
if wasStack {
// Detecting two stacks after another, possible cause lines match in
// our tests due to WithStack(WithStack(io.EOF)) on same line.
if detectStackboundaries {
if lines[l] {
if len(stack) == 0 {
return nil, errors.New("len of block must not be zero here")
}
blocks = append(blocks, stack)
stack = l
lines = map[string]bool{l: true}
continue
}
}
stack = stack + "\n" + l
} else {
stack = l
}
lines[l] = true
case !isStackLine && !wasStack:
blocks = append(blocks, l)
default:
return nil, errors.New("must not happen")
}
wasStack = isStackLine
}
// Use up stack
if stack != "" {
blocks = append(blocks, stack)
}
return blocks, nil
}
func testFormatCompleteCompare(t *testing.T, n int, arg interface{}, format string, want []string, detectStackBoundaries bool) {
gotStr := fmt.Sprintf(format, arg)
got, err := parseBlocks(gotStr, detectStackBoundaries)
if err != nil {
t.Fatal(err)
}
if len(got) != len(want) {
t.Fatalf("test %d: fmt.Sprintf(%s, err) -> wrong number of blocks: got(%d) want(%d)\n got: %s\nwant: %s\ngotStr: %q",
n+1, format, len(got), len(want), prettyBlocks(got), prettyBlocks(want), gotStr)
}
for i := range got {
if strings.ContainsAny(want[i], "\n") {
// Match as stack
match, err := regexp.MatchString(want[i], got[i])
if err != nil {
t.Fatal(err)
}
if !match {
t.Fatalf("test %d: block %d: fmt.Sprintf(%q, err):\ngot:\n%q\nwant:\n%q\nall-got:\n%s\nall-want:\n%s\n",
n+1, i+1, format, got[i], want[i], prettyBlocks(got), prettyBlocks(want))
}
} else {
// Match as message
if got[i] != want[i] {
t.Fatalf("test %d: fmt.Sprintf(%s, err) at block %d got != want:\n got: %q\nwant: %q", n+1, format, i+1, got[i], want[i])
}
}
}
}
type wrapper struct {
wrap func(err error) error
want []string
}
func prettyBlocks(blocks []string) string {
var out []string
for _, b := range blocks {
out = append(out, fmt.Sprintf("%v", b))
}
return " " + strings.Join(out, "\n ")
}
func testGenericRecursive(t *testing.T, beforeErr error, beforeWant []string, list []wrapper, maxDepth int) {
if len(beforeWant) == 0 {
panic("beforeWant must not be empty")
}
for _, w := range list {
if len(w.want) == 0 {
panic("want must not be empty")
}
err := w.wrap(beforeErr)
// Copy required cause append(beforeWant, ..) modified beforeWant subtly.
beforeCopy := make([]string, len(beforeWant))
copy(beforeCopy, beforeWant)
beforeWant := beforeCopy
last := len(beforeWant) - 1
var want []string
// Merge two stacks behind each other.
if strings.ContainsAny(beforeWant[last], "\n") && strings.ContainsAny(w.want[0], "\n") {
want = append(beforeWant[:last], append([]string{beforeWant[last] + "((?s).*)" + w.want[0]}, w.want[1:]...)...)
} else {
want = append(beforeWant, w.want...)
}
testFormatCompleteCompare(t, maxDepth, err, "%+v", want, false)
if maxDepth > 0 {
testGenericRecursive(t, err, want, list, maxDepth-1)
}
}
}
================================================
FILE: go113.go
================================================
// +build go1.13
package errors
import (
stderrors "errors"
)
// Is reports whether any error in err's chain matches target.
//
// The chain consists of err itself followed by the sequence of errors obtained by
// repeatedly calling Unwrap.
//
// An error is considered to match a target if it is equal to that target or if
// it implements a method Is(error) bool such that Is(target) returns true.
func Is(err, target error) bool { return stderrors.Is(err, target) }
// As finds the first error in err's chain that matches target, and if so, sets
// target to that error value and returns true.
//
// The chain consists of err itself followed by the sequence of errors obtained by
// repeatedly calling Unwrap.
//
// An error matches target if the error's concrete value is assignable to the value
// pointed to by target, or if the error has a method As(interface{}) bool such that
// As(target) returns true. In the latter case, the As method is responsible for
// setting target.
//
// As will panic if target is not a non-nil pointer to either a type that implements
// error, or to any interface type. As returns false if err is nil.
func As(err error, target interface{}) bool { return stderrors.As(err, target) }
// Unwrap returns the result of calling the Unwrap method on err, if err's
// type contains an Unwrap method returning error.
// Otherwise, Unwrap returns nil.
func Unwrap(err error) error {
return stderrors.Unwrap(err)
}
================================================
FILE: go113_test.go
================================================
// +build go1.13
package errors
import (
stderrors "errors"
"fmt"
"reflect"
"testing"
)
func TestErrorChainCompat(t *testing.T) {
err := stderrors.New("error that gets wrapped")
wrapped := Wrap(err, "wrapped up")
if !stderrors.Is(wrapped, err) {
t.Errorf("Wrap does not support Go 1.13 error chains")
}
}
func TestIs(t *testing.T) {
err := New("test")
type args struct {
err error
target error
}
tests := []struct {
name string
args args
want bool
}{
{
name: "with stack",
args: args{
err: WithStack(err),
target: err,
},
want: true,
},
{
name: "with message",
args: args{
err: WithMessage(err, "test"),
target: err,
},
want: true,
},
{
name: "with message format",
args: args{
err: WithMessagef(err, "%s", "test"),
target: err,
},
want: true,
},
{
name: "std errors compatibility",
args: args{
err: fmt.Errorf("wrap it: %w", err),
target: err,
},
want: true,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if got := Is(tt.args.err, tt.args.target); got != tt.want {
t.Errorf("Is() = %v, want %v", got, tt.want)
}
})
}
}
type customErr struct {
msg string
}
func (c customErr) Error() string { return c.msg }
func TestAs(t *testing.T) {
var err = customErr{msg: "test message"}
type args struct {
err error
target interface{}
}
tests := []struct {
name string
args args
want bool
}{
{
name: "with stack",
args: args{
err: WithStack(err),
target: new(customErr),
},
want: true,
},
{
name: "with message",
args: args{
err: WithMessage(err, "test"),
target: new(customErr),
},
want: true,
},
{
name: "with message format",
args: args{
err: WithMessagef(err, "%s", "test"),
target: new(customErr),
},
want: true,
},
{
name: "std errors compatibility",
args: args{
err: fmt.Errorf("wrap it: %w", err),
target: new(customErr),
},
want: true,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if got := As(tt.args.err, tt.args.target); got != tt.want {
t.Errorf("As() = %v, want %v", got, tt.want)
}
ce := tt.args.target.(*customErr)
if !reflect.DeepEqual(err, *ce) {
t.Errorf("set target error failed, target error is %v", *ce)
}
})
}
}
func TestUnwrap(t *testing.T) {
err := New("test")
type args struct {
err error
}
tests := []struct {
name string
args args
want error
}{
{
name: "with stack",
args: args{err: WithStack(err)},
want: err,
},
{
name: "with message",
args: args{err: WithMessage(err, "test")},
want: err,
},
{
name: "with message format",
args: args{err: WithMessagef(err, "%s", "test")},
want: err,
},
{
name: "std errors compatibility",
args: args{err: fmt.Errorf("wrap: %w", err)},
want: err,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if err := Unwrap(tt.args.err); !reflect.DeepEqual(err, tt.want) {
t.Errorf("Unwrap() error = %v, want %v", err, tt.want)
}
})
}
}
================================================
FILE: json_test.go
================================================
package errors
import (
"encoding/json"
"regexp"
"testing"
)
func TestFrameMarshalText(t *testing.T) {
var tests = []struct {
Frame
want string
}{{
initpc,
`^github.com/pkg/errors\.init(\.ializers)? .+/github\.com/pkg/errors/stack_test.go:\d+$`,
}, {
0,
`^unknown$`,
}}
for i, tt := range tests {
got, err := tt.Frame.MarshalText()
if err != nil {
t.Fatal(err)
}
if !regexp.MustCompile(tt.want).Match(got) {
t.Errorf("test %d: MarshalJSON:\n got %q\n want %q", i+1, string(got), tt.want)
}
}
}
func TestFrameMarshalJSON(t *testing.T) {
var tests = []struct {
Frame
want string
}{{
initpc,
`^"github\.com/pkg/errors\.init(\.ializers)? .+/github\.com/pkg/errors/stack_test.go:\d+"$`,
}, {
0,
`^"unknown"$`,
}}
for i, tt := range tests {
got, err := json.Marshal(tt.Frame)
if err != nil {
t.Fatal(err)
}
if !regexp.MustCompile(tt.want).Match(got) {
t.Errorf("test %d: MarshalJSON:\n got %q\n want %q", i+1, string(got), tt.want)
}
}
}
================================================
FILE: stack.go
================================================
package errors
import (
"fmt"
"io"
"path"
"runtime"
"strconv"
"strings"
)
// Frame represents a program counter inside a stack frame.
// For historical reasons if Frame is interpreted as a uintptr
// its value represents the program counter + 1.
type Frame uintptr
// pc returns the program counter for this frame;
// multiple frames may have the same PC value.
func (f Frame) pc() uintptr { return uintptr(f) - 1 }
// file returns the full path to the file that contains the
// function for this Frame's pc.
func (f Frame) file() string {
fn := runtime.FuncForPC(f.pc())
if fn == nil {
return "unknown"
}
file, _ := fn.FileLine(f.pc())
return file
}
// line returns the line number of source code of the
// function for this Frame's pc.
func (f Frame) line() int {
fn := runtime.FuncForPC(f.pc())
if fn == nil {
return 0
}
_, line := fn.FileLine(f.pc())
return line
}
// name returns the name of this function, if known.
func (f Frame) name() string {
fn := runtime.FuncForPC(f.pc())
if fn == nil {
return "unknown"
}
return fn.Name()
}
// Format formats the frame according to the fmt.Formatter interface.
//
// %s source file
// %d source line
// %n function name
// %v equivalent to %s:%d
//
// Format accepts flags that alter the printing of some verbs, as follows:
//
// %+s function name and path of source file relative to the compile time
// GOPATH separated by \n\t (<funcname>\n\t<path>)
// %+v equivalent to %+s:%d
func (f Frame) Format(s fmt.State, verb rune) {
switch verb {
case 's':
switch {
case s.Flag('+'):
io.WriteString(s, f.name())
io.WriteString(s, "\n\t")
io.WriteString(s, f.file())
default:
io.WriteString(s, path.Base(f.file()))
}
case 'd':
io.WriteString(s, strconv.Itoa(f.line()))
case 'n':
io.WriteString(s, funcname(f.name()))
case 'v':
f.Format(s, 's')
io.WriteString(s, ":")
f.Format(s, 'd')
}
}
// MarshalText formats a stacktrace Frame as a text string. The output is the
// same as that of fmt.Sprintf("%+v", f), but without newlines or tabs.
func (f Frame) MarshalText() ([]byte, error) {
name := f.name()
if name == "unknown" {
return []byte(name), nil
}
return []byte(fmt.Sprintf("%s %s:%d", name, f.file(), f.line())), nil
}
// StackTrace is stack of Frames from innermost (newest) to outermost (oldest).
type StackTrace []Frame
// Format formats the stack of Frames according to the fmt.Formatter interface.
//
// %s lists source files for each Frame in the stack
// %v lists the source file and line number for each Frame in the stack
//
// Format accepts flags that alter the printing of some verbs, as follows:
//
// %+v Prints filename, function, and line number for each Frame in the stack.
func (st StackTrace) Format(s fmt.State, verb rune) {
switch verb {
case 'v':
switch {
case s.Flag('+'):
for _, f := range st {
io.WriteString(s, "\n")
f.Format(s, verb)
}
case s.Flag('#'):
fmt.Fprintf(s, "%#v", []Frame(st))
default:
st.formatSlice(s, verb)
}
case 's':
st.formatSlice(s, verb)
}
}
// formatSlice will format this StackTrace into the given buffer as a slice of
// Frame, only valid when called with '%s' or '%v'.
func (st StackTrace) formatSlice(s fmt.State, verb rune) {
io.WriteString(s, "[")
for i, f := range st {
if i > 0 {
io.WriteString(s, " ")
}
f.Format(s, verb)
}
io.WriteString(s, "]")
}
// stack represents a stack of program counters.
type stack []uintptr
func (s *stack) Format(st fmt.State, verb rune) {
switch verb {
case 'v':
switch {
case st.Flag('+'):
for _, pc := range *s {
f := Frame(pc)
fmt.Fprintf(st, "\n%+v", f)
}
}
}
}
func (s *stack) StackTrace() StackTrace {
f := make([]Frame, len(*s))
for i := 0; i < len(f); i++ {
f[i] = Frame((*s)[i])
}
return f
}
func callers() *stack {
const depth = 32
var pcs [depth]uintptr
n := runtime.Callers(3, pcs[:])
var st stack = pcs[0:n]
return &st
}
// funcname removes the path prefix component of a function's name reported by func.Name().
func funcname(name string) string {
i := strings.LastIndex(name, "/")
name = name[i+1:]
i = strings.Index(name, ".")
return name[i+1:]
}
================================================
FILE: stack_test.go
================================================
package errors
import (
"fmt"
"runtime"
"testing"
)
var initpc = caller()
type X struct{}
// val returns a Frame pointing to itself.
func (x X) val() Frame {
return caller()
}
// ptr returns a Frame pointing to itself.
func (x *X) ptr() Frame {
return caller()
}
func TestFrameFormat(t *testing.T) {
var tests = []struct {
Frame
format string
want string
}{{
initpc,
"%s",
"stack_test.go",
}, {
initpc,
"%+s",
"github.com/pkg/errors.init\n" +
"\t.+/github.com/pkg/errors/stack_test.go",
}, {
0,
"%s",
"unknown",
}, {
0,
"%+s",
"unknown",
}, {
initpc,
"%d",
"9",
}, {
0,
"%d",
"0",
}, {
initpc,
"%n",
"init",
}, {
func() Frame {
var x X
return x.ptr()
}(),
"%n",
`\(\*X\).ptr`,
}, {
func() Frame {
var x X
return x.val()
}(),
"%n",
"X.val",
}, {
0,
"%n",
"",
}, {
initpc,
"%v",
"stack_test.go:9",
}, {
initpc,
"%+v",
"github.com/pkg/errors.init\n" +
"\t.+/github.com/pkg/errors/stack_test.go:9",
}, {
0,
"%v",
"unknown:0",
}}
for i, tt := range tests {
testFormatRegexp(t, i, tt.Frame, tt.format, tt.want)
}
}
func TestFuncname(t *testing.T) {
tests := []struct {
name, want string
}{
{"", ""},
{"runtime.main", "main"},
{"github.com/pkg/errors.funcname", "funcname"},
{"funcname", "funcname"},
{"io.copyBuffer", "copyBuffer"},
{"main.(*R).Write", "(*R).Write"},
}
for _, tt := range tests {
got := funcname(tt.name)
want := tt.want
if got != want {
t.Errorf("funcname(%q): want: %q, got %q", tt.name, want, got)
}
}
}
func TestStackTrace(t *testing.T) {
tests := []struct {
err error
want []string
}{{
New("ooh"), []string{
"github.com/pkg/errors.TestStackTrace\n" +
"\t.+/github.com/pkg/errors/stack_test.go:121",
},
}, {
Wrap(New("ooh"), "ahh"), []string{
"github.com/pkg/errors.TestStackTrace\n" +
"\t.+/github.com/pkg/errors/stack_test.go:126", // this is the stack of Wrap, not New
},
}, {
Cause(Wrap(New("ooh"), "ahh")), []string{
"github.com/pkg/errors.TestStackTrace\n" +
"\t.+/github.com/pkg/errors/stack_test.go:131", // this is the stack of New
},
}, {
func() error { return New("ooh") }(), []string{
`github.com/pkg/errors.TestStackTrace.func1` +
"\n\t.+/github.com/pkg/errors/stack_test.go:136", // this is the stack of New
"github.com/pkg/errors.TestStackTrace\n" +
"\t.+/github.com/pkg/errors/stack_test.go:136", // this is the stack of New's caller
},
}, {
Cause(func() error {
return func() error {
return Errorf("hello %s", fmt.Sprintf("world: %s", "ooh"))
}()
}()), []string{
`github.com/pkg/errors.TestStackTrace.func2.1` +
"\n\t.+/github.com/pkg/errors/stack_test.go:145", // this is the stack of Errorf
`github.com/pkg/errors.TestStackTrace.func2` +
"\n\t.+/github.com/pkg/errors/stack_test.go:146", // this is the stack of Errorf's caller
"github.com/pkg/errors.TestStackTrace\n" +
"\t.+/github.com/pkg/errors/stack_test.go:147", // this is the stack of Errorf's caller's caller
},
}}
for i, tt := range tests {
x, ok := tt.err.(interface {
StackTrace() StackTrace
})
if !ok {
t.Errorf("expected %#v to implement StackTrace() StackTrace", tt.err)
continue
}
st := x.StackTrace()
for j, want := range tt.want {
testFormatRegexp(t, i, st[j], "%+v", want)
}
}
}
func stackTrace() StackTrace {
const depth = 8
var pcs [depth]uintptr
n := runtime.Callers(1, pcs[:])
var st stack = pcs[0:n]
return st.StackTrace()
}
func TestStackTraceFormat(t *testing.T) {
tests := []struct {
StackTrace
format string
want string
}{{
nil,
"%s",
`\[\]`,
}, {
nil,
"%v",
`\[\]`,
}, {
nil,
"%+v",
"",
}, {
nil,
"%#v",
`\[\]errors.Frame\(nil\)`,
}, {
make(StackTrace, 0),
"%s",
`\[\]`,
}, {
make(StackTrace, 0),
"%v",
`\[\]`,
}, {
make(StackTrace, 0),
"%+v",
"",
}, {
make(StackTrace, 0),
"%#v",
`\[\]errors.Frame{}`,
}, {
stackTrace()[:2],
"%s",
`\[stack_test.go stack_test.go\]`,
}, {
stackTrace()[:2],
"%v",
`\[stack_test.go:174 stack_test.go:221\]`,
}, {
stackTrace()[:2],
"%+v",
"\n" +
"github.com/pkg/errors.stackTrace\n" +
"\t.+/github.com/pkg/errors/stack_test.go:174\n" +
"github.com/pkg/errors.TestStackTraceFormat\n" +
"\t.+/github.com/pkg/errors/stack_test.go:225",
}, {
stackTrace()[:2],
"%#v",
`\[\]errors.Frame{stack_test.go:174, stack_test.go:233}`,
}}
for i, tt := range tests {
testFormatRegexp(t, i, tt.StackTrace, tt.format, tt.want)
}
}
// a version of runtime.Caller that returns a Frame, not a uintptr.
func caller() Frame {
var pcs [3]uintptr
n := runtime.Callers(2, pcs[:])
frames := runtime.CallersFrames(pcs[:n])
frame, _ := frames.Next()
return Frame(frame.PC)
}
gitextract_u9vo6na2/ ├── .gitignore ├── .travis.yml ├── LICENSE ├── Makefile ├── README.md ├── appveyor.yml ├── bench_test.go ├── errors.go ├── errors_test.go ├── example_test.go ├── format_test.go ├── go113.go ├── go113_test.go ├── json_test.go ├── stack.go └── stack_test.go
SYMBOL INDEX (103 symbols across 10 files)
FILE: bench_test.go
function noErrors (line 12) | func noErrors(at, depth int) error {
function yesErrors (line 19) | func yesErrors(at, depth int) error {
function BenchmarkErrors (line 30) | func BenchmarkErrors(b *testing.B) {
function BenchmarkStackFormatting (line 65) | func BenchmarkStackFormatting(b *testing.B) {
FILE: errors.go
function New (line 102) | func New(message string) error {
function Errorf (line 112) | func Errorf(format string, args ...interface{}) error {
type fundamental (line 120) | type fundamental struct
method Error (line 125) | func (f *fundamental) Error() string { return f.msg }
method Format (line 127) | func (f *fundamental) Format(s fmt.State, verb rune) {
function WithStack (line 145) | func WithStack(err error) error {
type withStack (line 155) | type withStack struct
method Cause (line 160) | func (w *withStack) Cause() error { return w.error }
method Unwrap (line 163) | func (w *withStack) Unwrap() error { return w.error }
method Format (line 165) | func (w *withStack) Format(s fmt.State, verb rune) {
function Wrap (line 184) | func Wrap(err error, message string) error {
function Wrapf (line 201) | func Wrapf(err error, format string, args ...interface{}) error {
function WithMessage (line 217) | func WithMessage(err error, message string) error {
function WithMessagef (line 229) | func WithMessagef(err error, format string, args ...interface{}) error {
type withMessage (line 239) | type withMessage struct
method Error (line 244) | func (w *withMessage) Error() string { return w.msg + ": " + w.cause.E...
method Cause (line 245) | func (w *withMessage) Cause() error { return w.cause }
method Unwrap (line 248) | func (w *withMessage) Unwrap() error { return w.cause }
method Format (line 250) | func (w *withMessage) Format(s fmt.State, verb rune) {
function Cause (line 275) | func Cause(err error) error {
FILE: errors_test.go
function TestNew (line 11) | func TestNew(t *testing.T) {
function TestWrapNil (line 30) | func TestWrapNil(t *testing.T) {
function TestWrap (line 37) | func TestWrap(t *testing.T) {
type nilError (line 55) | type nilError struct
method Error (line 57) | func (nilError) Error() string { return "nil error" }
function TestCause (line 59) | func TestCause(t *testing.T) {
function TestWrapfNil (line 109) | func TestWrapfNil(t *testing.T) {
function TestWrapf (line 116) | func TestWrapf(t *testing.T) {
function TestErrorf (line 135) | func TestErrorf(t *testing.T) {
function TestWithStackNil (line 152) | func TestWithStackNil(t *testing.T) {
function TestWithStack (line 159) | func TestWithStack(t *testing.T) {
function TestWithMessageNil (line 176) | func TestWithMessageNil(t *testing.T) {
function TestWithMessage (line 183) | func TestWithMessage(t *testing.T) {
function TestWithMessagefNil (line 201) | func TestWithMessagefNil(t *testing.T) {
function TestWithMessagef (line 208) | func TestWithMessagef(t *testing.T) {
function TestErrorEquality (line 231) | func TestErrorEquality(t *testing.T) {
FILE: example_test.go
function ExampleNew (line 9) | func ExampleNew() {
function ExampleNew_printf (line 16) | func ExampleNew_printf() {
function ExampleWithMessage (line 38) | func ExampleWithMessage() {
function ExampleWithStack (line 46) | func ExampleWithStack() {
function ExampleWithStack_printf (line 54) | func ExampleWithStack_printf() {
function ExampleWrap (line 91) | func ExampleWrap() {
function fn (line 99) | func fn() error {
function ExampleCause (line 106) | func ExampleCause() {
function ExampleWrap_extended (line 115) | func ExampleWrap_extended() {
function ExampleWrapf (line 145) | func ExampleWrapf() {
function ExampleErrorf_extended (line 153) | func ExampleErrorf_extended() {
function Example_stackTrace (line 175) | func Example_stackTrace() {
function ExampleCause_printf (line 195) | func ExampleCause_printf() {
FILE: format_test.go
function TestFormatNew (line 12) | func TestFormatNew(t *testing.T) {
function TestFormatErrorf (line 42) | func TestFormatErrorf(t *testing.T) {
function TestFormatWrap (line 68) | func TestFormatWrap(t *testing.T) {
function TestFormatWrapf (line 120) | func TestFormatWrapf(t *testing.T) {
function TestFormatWithStack (line 161) | func TestFormatWithStack(t *testing.T) {
function TestFormatWithMessage (line 230) | func TestFormatWithMessage(t *testing.T) {
function TestFormatGeneric (line 310) | func TestFormatGeneric(t *testing.T) {
function wrappedNew (line 363) | func wrappedNew(message string) error { // This function will be mid-sta...
function TestFormatWrappedNew (line 367) | func TestFormatWrappedNew(t *testing.T) {
function testFormatRegexp (line 387) | func testFormatRegexp(t *testing.T, n int, arg interface{}, format, want...
function parseBlocks (line 428) | func parseBlocks(input string, detectStackboundaries bool) ([]string, er...
function testFormatCompleteCompare (line 481) | func testFormatCompleteCompare(t *testing.T, n int, arg interface{}, for...
type wrapper (line 514) | type wrapper struct
function prettyBlocks (line 519) | func prettyBlocks(blocks []string) string {
function testGenericRecursive (line 529) | func testGenericRecursive(t *testing.T, beforeErr error, beforeWant []st...
FILE: go113.go
function Is (line 16) | func Is(err, target error) bool { return stderrors.Is(err, target) }
function As (line 31) | func As(err error, target interface{}) bool { return stderrors.As(err, t...
function Unwrap (line 36) | func Unwrap(err error) error {
FILE: go113_test.go
function TestErrorChainCompat (line 12) | func TestErrorChainCompat(t *testing.T) {
function TestIs (line 20) | func TestIs(t *testing.T) {
type customErr (line 74) | type customErr struct
method Error (line 78) | func (c customErr) Error() string { return c.msg }
function TestAs (line 80) | func TestAs(t *testing.T) {
function TestUnwrap (line 139) | func TestUnwrap(t *testing.T) {
FILE: json_test.go
function TestFrameMarshalText (line 9) | func TestFrameMarshalText(t *testing.T) {
function TestFrameMarshalJSON (line 31) | func TestFrameMarshalJSON(t *testing.T) {
FILE: stack.go
type Frame (line 15) | type Frame
method pc (line 19) | func (f Frame) pc() uintptr { return uintptr(f) - 1 }
method file (line 23) | func (f Frame) file() string {
method line (line 34) | func (f Frame) line() int {
method name (line 44) | func (f Frame) name() string {
method Format (line 64) | func (f Frame) Format(s fmt.State, verb rune) {
method MarshalText (line 88) | func (f Frame) MarshalText() ([]byte, error) {
type StackTrace (line 97) | type StackTrace
method Format (line 107) | func (st StackTrace) Format(s fmt.State, verb rune) {
method formatSlice (line 128) | func (st StackTrace) formatSlice(s fmt.State, verb rune) {
type stack (line 140) | type stack
method Format (line 142) | func (s *stack) Format(st fmt.State, verb rune) {
method StackTrace (line 155) | func (s *stack) StackTrace() StackTrace {
function callers (line 163) | func callers() *stack {
function funcname (line 172) | func funcname(name string) string {
FILE: stack_test.go
type X (line 11) | type X struct
method val (line 14) | func (x X) val() Frame {
method ptr (line 19) | func (x *X) ptr() Frame {
function TestFrameFormat (line 23) | func TestFrameFormat(t *testing.T) {
function TestFuncname (line 95) | func TestFuncname(t *testing.T) {
function TestStackTrace (line 116) | func TestStackTrace(t *testing.T) {
function stackTrace (line 171) | func stackTrace() StackTrace {
function TestStackTraceFormat (line 179) | func TestStackTraceFormat(t *testing.T) {
function caller (line 244) | func caller() Frame {
Condensed preview — 16 files, each showing path, character count, and a content snippet. Download the .json file or copy for the full structured content (62K chars).
[
{
"path": ".gitignore",
"chars": 266,
"preview": "# Compiled Object files, Static and Dynamic libs (Shared Objects)\n*.o\n*.a\n*.so\n\n# Folders\n_obj\n_test\n\n# Architecture spe"
},
{
"path": ".travis.yml",
"chars": 124,
"preview": "arch:\n - amd64\n \nlanguage: go\ngo_import_path: github.com/pkg/errors\ngo:\n - 1.14\n - 1.15\n - tip\n\nscript:\n - make ch"
},
{
"path": "LICENSE",
"chars": 1312,
"preview": "Copyright (c) 2015, Dave Cheney <dave@cheney.net>\nAll rights reserved.\n\nRedistribution and use in source and binary form"
},
{
"path": "Makefile",
"chars": 871,
"preview": "PKGS := github.com/pkg/errors\nSRCDIRS := $(shell go list -f '{{.Dir}}' $(PKGS))\nGO := go\n\ncheck: test vet gofmt misspell"
},
{
"path": "README.md",
"chars": 2717,
"preview": "# errors [](https://travis-ci.org/pkg/errors) [![AppVeyor](https://ci."
},
{
"path": "appveyor.yml",
"chars": 639,
"preview": "version: build-{build}.{branch}\n\nclone_folder: C:\\gopath\\src\\github.com\\pkg\\errors\nshallow_clone: true # for startup spe"
},
{
"path": "bench_test.go",
"chars": 1983,
"preview": "// +build go1.7\n\npackage errors\n\nimport (\n\t\"fmt\"\n\t\"testing\"\n\n\tstderrors \"errors\"\n)\n\nfunc noErrors(at, depth int) error {"
},
{
"path": "errors.go",
"chars": 7439,
"preview": "// Package errors provides simple error handling primitives.\n//\n// The traditional error handling idiom in Go is roughly"
},
{
"path": "errors_test.go",
"chars": 5669,
"preview": "package errors\n\nimport (\n\t\"errors\"\n\t\"fmt\"\n\t\"io\"\n\t\"reflect\"\n\t\"testing\"\n)\n\nfunc TestNew(t *testing.T) {\n\ttests := []struct"
},
{
"path": "example_test.go",
"chars": 5415,
"preview": "package errors_test\n\nimport (\n\t\"fmt\"\n\n\t\"github.com/pkg/errors\"\n)\n\nfunc ExampleNew() {\n\terr := errors.New(\"whoops\")\n\tfmt."
},
{
"path": "format_test.go",
"chars": 13361,
"preview": "package errors\n\nimport (\n\t\"errors\"\n\t\"fmt\"\n\t\"io\"\n\t\"regexp\"\n\t\"strings\"\n\t\"testing\"\n)\n\nfunc TestFormatNew(t *testing.T) {\n\tt"
},
{
"path": "go113.go",
"chars": 1451,
"preview": "// +build go1.13\n\npackage errors\n\nimport (\n\tstderrors \"errors\"\n)\n\n// Is reports whether any error in err's chain matches"
},
{
"path": "go113_test.go",
"chars": 3148,
"preview": "// +build go1.13\n\npackage errors\n\nimport (\n\tstderrors \"errors\"\n\t\"fmt\"\n\t\"reflect\"\n\t\"testing\"\n)\n\nfunc TestErrorChainCompat"
},
{
"path": "json_test.go",
"chars": 1006,
"preview": "package errors\n\nimport (\n\t\"encoding/json\"\n\t\"regexp\"\n\t\"testing\"\n)\n\nfunc TestFrameMarshalText(t *testing.T) {\n\tvar tests ="
},
{
"path": "stack.go",
"chars": 4221,
"preview": "package errors\n\nimport (\n\t\"fmt\"\n\t\"io\"\n\t\"path\"\n\t\"runtime\"\n\t\"strconv\"\n\t\"strings\"\n)\n\n// Frame represents a program counter "
},
{
"path": "stack_test.go",
"chars": 4813,
"preview": "package errors\n\nimport (\n\t\"fmt\"\n\t\"runtime\"\n\t\"testing\"\n)\n\nvar initpc = caller()\n\ntype X struct{}\n\n// val returns a Frame "
}
]
About this extraction
This page contains the full source code of the pkg/errors GitHub repository, extracted and formatted as plain text for AI agents and large language models (LLMs). The extraction includes 16 files (53.2 KB), approximately 16.5k tokens, and a symbol index with 103 extracted functions, classes, methods, constants, and types. Use this with OpenClaw, Claude, ChatGPT, Cursor, Windsurf, or any other AI tool that accepts text input. You can copy the full output to your clipboard or download it as a .txt file.
Extracted by GitExtract — free GitHub repo to text converter for AI. Built by Nikandr Surkov.