How to use Panic method of internal Package

...17	err := safe.Do(func() error {18		_ = getName()19		return nil20	})21	if err, ok := err.(safe.PanicError); ok {22		fmt.Println(err)23	}24	// Output:25	// panic: unhandled error26}27func ExampleDoWithResult() {28	getName := func() string {29		panic("unhandled error")30	}31	_, err := safe.DoWithResult(func() (interface{}, error) {32		_ = getName()33		return nil, nil34	})35	if err, ok := err.(safe.PanicError); ok {36		fmt.Println(err)37	}38	// Output:39	// panic: unhandled error40}41func ExampleDoWithResult_ok() {42	getName := func() string {43		return "OK"44	}45	res, err := safe.DoWithResult(func() (interface{}, error) {46		return getName(), nil47	})48	if err, ok := err.(safe.PanicError); ok {49		fmt.Println(err)50	} else {51		fmt.Println(res.(string))52	}53	// Output:54	// OK55}56func ExampleGo() {57	safe.SetPanicHandler(func(err error) {58		fmt.Println(err)59	})60	var wg sync.WaitGroup61	wg.Add(1)62	safe.Go(func() {63		defer wg.Done()64		panic("unhandled error")65	})66	wg.Wait()67	// Output:68	// panic: unhandled error69}70func ExampleGroup() {71	var g safe.Group72	g.Go(func() error {73		panic("unhandled error")74	})75	err := g.Wait()76	fmt.Printf("(%T) %v\n", err, err)77	// Output:78	// (safe.PanicError) panic: unhandled error79}80type testError string81func (err testError) Error() string {82	return string(err)83}84func TestDo(t *testing.T) {85	t.Run("with panic", func(t *testing.T) {86		err := safe.Do(func() error {87			panic("internal error")88		})89		if err == nil {90			t.Fatal("expected error")91		}92		assert.Equal(t, err.Error(), "panic: internal error")93		panicErr, ok := err.(safe.PanicError)94		if !ok {95			t.Fatal("err not a safe.PanicError")96		}97		assert.Equal(t, panicErr.Panic(), "internal error")98	})99	t.Run("with error", func(t *testing.T) {100		err := safe.Do(func() error {101			return testError("internal error")102		})103		assert.Equal(t, err.Error(), "internal error")104		assert.Equal(t, reflect.TypeOf(err).String(), "safe_test.testError")105	})106}107func TestDoWithResult(t *testing.T) {108	t.Run("with panic", func(t *testing.T) {109		_, err := safe.DoWithResult(func() (interface{}, error) {110			panic("internal error")111		})112		if err == nil {113			t.Fatal("expected error")114		}115		assert.Equal(t, err.Error(), "panic: internal error")116		panicErr, ok := err.(safe.PanicError)117		if !ok {118			t.Fatal("err not a safe.PanicError")119		}120		assert.Equal(t, panicErr.Panic(), "internal error")121	})122	t.Run("with error", func(t *testing.T) {123		_, err := safe.DoWithResult(func() (interface{}, error) {124			return nil, testError("internal error")125		})126		assert.Equal(t, err.Error(), "internal error")127		assert.Equal(t, reflect.TypeOf(err).String(), "safe_test.testError")128	})129	t.Run("with result", func(t *testing.T) {130		res, err := safe.DoWithResult(func() (interface{}, error) {131			return "foo", nil132		})133		if err != nil {134			t.Fatal("expected no error")135		}136		assert.Equal(t, res.(string), "foo")137	})138}139func TestGroup(t *testing.T) {140	var g safe.Group141	g.Go(func() error { return nil })142	g.Go(func() error { panic("internal error") })143	err := g.Wait()144	if err == nil {145		t.Fatal("expected error")146	}147	assert.Equal(t, err.Error(), "panic: internal error")148	panicErr, ok := err.(safe.PanicError)149	if !ok {150		t.Fatal("err not a safe.PanicError")151	}152	assert.Equal(t, panicErr.Panic(), "internal error")153}154func TestGo(t *testing.T) {155	// Note: these tests necessarily mutate global state, and cannot be run in156	// parallel.157	t.Run("no handler", func(t *testing.T) {158		safe.SetPanicHandler(nil)159		var b logBuffer160		log.SetOutput(&b)161		log.SetFlags(0)162		b.Add()163		safe.Go(func() {164			panic("internal error")165		})166		b.Wait()167		assert.True(t, strings.HasPrefix(b.String(), "panic: internal error"))168		assert.Contains(t, b.String(), "safe-go_test.TestGo") // contains a stack trace169	})170	t.Run("with handler", func(t *testing.T) {171		var wg sync.WaitGroup172		// Set up a panic handler.173		wg.Add(1)174		var handledErr error175		safe.SetPanicHandler(func(err error) {176			handledErr = err177			wg.Done()178		})179		// Run a background goroutine that panics.180		wg.Add(1)181		safe.Go(func() {182			defer wg.Done()183			panic("internal error")184		})185		wg.Wait() // wait for goroutine and panic handler186		// Assert the panic was passed to the panic handler.187		panicErr, ok := handledErr.(safe.PanicError)188		if !ok {189			t.Fatal("err not a safe.PanicError")190		}191		assert.Equal(t, panicErr.Panic(), "internal error")192	})193	t.Run("panic in handler", func(t *testing.T) {194		var b logBuffer195		log.SetOutput(&b)196		log.SetFlags(0)197		// Configure a panic handler that panics.198		var wg sync.WaitGroup199		wg.Add(1)200		safe.SetPanicHandler(func(err error) {201			defer wg.Done()202			panic("worst panic handler")203		})204		// Run a background goroutine that panics.205		wg.Add(1)206		b.Add()207		safe.Go(func() {208			defer wg.Done()209			panic("internal error")210		})211		wg.Wait() // wait for goroutine and panic handler212		b.Wait()  // wait for log to be written213		assert.Contains(t, b.String(), "panic in panic handler") // prefix214		assert.Contains(t, b.String(), "worst panic handler")    // panic handler panic...

1// Copyright 2019 The Go Authors. All rights reserved.2// Use of this source code is governed by a BSD-style3// license that can be found in the LICENSE file.4// Package protolegacy is a stub version of the v1 proto package5// to satisfy internal/testprotos/legacy dependencies.6package protolegacy7import (8	"bytes"9	"compress/gzip"10	"errors"11	"fmt"12	"io/ioutil"13	"google.golang.org/protobuf/reflect/protoreflect"14	"google.golang.org/protobuf/reflect/protoregistry"15	"google.golang.org/protobuf/runtime/protoiface"16	"google.golang.org/protobuf/runtime/protoimpl"17)18const (19	ProtoPackageIsVersion1 = true20	ProtoPackageIsVersion2 = true21	ProtoPackageIsVersion3 = true22)23const (24	WireVarint     = 025	WireFixed32    = 526	WireFixed64    = 127	WireBytes      = 228	WireStartGroup = 329	WireEndGroup   = 430)31type (32	Message                = protoiface.MessageV133	ExtensionRange         = protoiface.ExtensionRangeV134	ExtensionDesc          = protoimpl.ExtensionInfo35	Extension              = protoimpl.ExtensionFieldV136	XXX_InternalExtensions = protoimpl.ExtensionFields37)38func RegisterFile(s string, d []byte) {39	// Decompress the descriptor.40	zr, err := gzip.NewReader(bytes.NewReader(d))41	if err != nil {42		panic(fmt.Sprintf("proto: invalid compressed file descriptor: %v", err))43	}44	b, err := ioutil.ReadAll(zr)45	if err != nil {46		panic(fmt.Sprintf("proto: invalid compressed file descriptor: %v", err))47	}48	// Construct a protoreflect.FileDescriptor from the raw descriptor.49	// Note that DescBuilder.Build automatically registers the constructed50	// file descriptor with the v2 registry.51	protoimpl.DescBuilder{RawDescriptor: b}.Build()52}53func RegisterType(m Message, s string) {54	mt := protoimpl.X.LegacyMessageTypeOf(m, protoreflect.FullName(s))55	if err := protoregistry.GlobalTypes.RegisterMessage(mt); err != nil {56		panic(err)57	}58}59func RegisterMapType(interface{}, string) {60	// Do nothing.61}62func RegisterEnum(string, map[int32]string, map[string]int32) {63	// Do nothing.64}65func RegisterExtension(d *ExtensionDesc) {66	if err := protoregistry.GlobalTypes.RegisterExtension(d); err != nil {67		panic(err)68	}69}70var ErrInternalBadWireType = errors.New("not implemented")71func Size(Message) int                { panic("not implemented") }72func Marshal(Message) ([]byte, error) { panic("not implemented") }73func Unmarshal([]byte, Message) error { panic("not implemented") }74func SizeVarint(uint64) int             { panic("not implemented") }75func EncodeVarint(uint64) []byte        { panic("not implemented") }76func DecodeVarint([]byte) (uint64, int) { panic("not implemented") }77func CompactTextString(Message) string                                  { panic("not implemented") }78func EnumName(map[int32]string, int32) string                           { panic("not implemented") }79func UnmarshalJSONEnum(map[string]int32, []byte, string) (int32, error) { panic("not implemented") }80type Buffer struct{}81func (*Buffer) DecodeFixed32() (uint64, error)      { panic("not implemented") }82func (*Buffer) DecodeFixed64() (uint64, error)      { panic("not implemented") }83func (*Buffer) DecodeGroup(Message) error           { panic("not implemented") }84func (*Buffer) DecodeMessage(Message) error         { panic("not implemented") }85func (*Buffer) DecodeRawBytes(bool) ([]byte, error) { panic("not implemented") }86func (*Buffer) DecodeStringBytes() (string, error)  { panic("not implemented") }87func (*Buffer) DecodeVarint() (uint64, error)       { panic("not implemented") }88func (*Buffer) DecodeZigzag32() (uint64, error)     { panic("not implemented") }89func (*Buffer) DecodeZigzag64() (uint64, error)     { panic("not implemented") }90func (*Buffer) EncodeFixed32(uint64) error          { panic("not implemented") }91func (*Buffer) EncodeFixed64(uint64) error          { panic("not implemented") }92func (*Buffer) EncodeMessage(Message) error         { panic("not implemented") }93func (*Buffer) EncodeRawBytes([]byte) error         { panic("not implemented") }94func (*Buffer) EncodeStringBytes(string) error      { panic("not implemented") }95func (*Buffer) EncodeVarint(uint64) error           { panic("not implemented") }96func (*Buffer) EncodeZigzag32(uint64) error         { panic("not implemented") }97func (*Buffer) EncodeZigzag64(uint64) error         { panic("not implemented") }98func (*Buffer) Marshal(Message) error               { panic("not implemented") }99func (*Buffer) Unmarshal(Message) error             { panic("not implemented") }100type InternalMessageInfo struct{}101func (*InternalMessageInfo) DiscardUnknown(Message)                        { panic("not implemented") }102func (*InternalMessageInfo) Marshal([]byte, Message, bool) ([]byte, error) { panic("not implemented") }103func (*InternalMessageInfo) Merge(Message, Message)                        { panic("not implemented") }104func (*InternalMessageInfo) Size(Message) int                              { panic("not implemented") }105func (*InternalMessageInfo) Unmarshal(Message, []byte) error               { panic("not implemented") }...

1import "fmt"2func main() {3    fmt.Println("Hello, playground")4    panic("PANIC")5}6main.main()7main.main()8The recover() method is used to recover from a panic. It is used to recover from a panic. The recover() method is used to recover from a panic. It is used to recover from a panic. The recover() method is used to recover from a

1import (2func main() {3    fmt.Println("Hello World")4    internal.Panic()5}6import (7func main() {8    fmt.Println("Hello World")9    internal.Panic()10}11import "fmt"12func Panic() {13    fmt.Println("Panic")14}15./1.go:9: cannot range over files (type *[]os.FileInfo)16import (17func main() {18    fmt.Println("Hello World")19    files, err := os.ReadDir("test")20    if err != nil {21        fmt.Println(err)22    }23    for _, file := range files {24        fmt.Println(file.Name())25    }26}27./1.go:15:12: cannot use file (type *os.File) as type *os.File in argument to bufio.NewReader28import (29func main() {30    fmt.Println("Hello World")31    file, err := os.Open("test.txt")32    if err != nil {33        fmt.Println(err)34    }35    reader := bufio.NewReader(file)36    line, err := reader.ReadString('37    if err != nil {38        fmt.Println(err)39    }40    fmt.Println(line)41}

1import (2func main() {3	internal.Panic()4}5func Panic() {6	panic("panic from internal package")7}8import (9func TestPanic(t *testing.T) {10	Panic()11}12--- FAIL: TestPanic (0.00s)13testing.tRunner.func1(0xc4200a40f0)14panic(0x4a0e40, 0x4e9c20)15main.main()16import (17func TestPanic(t *testing.T) {18	defer func() {19		if r := recover(); r != nil {20			t.Errorf("Panic() = %v", r)21		}22	}()23	Panic()24}25--- FAIL: TestPanic (0.00s)26	internal_test.go:11: Panic() = panic from internal package27import (28func TestPanic(t *testing.T) {

1import (2func main() {3    fmt.Println("hello world")4    pqr.Panic()5}6github.com/abc/pqr.Panic(0x0, 0x0)7main.main()

1import "fmt"2import "main/internal"3func main() {4    fmt.Println("Hello, playground")5    internal.Panic()6}7main.main()8How to use init() in go?

1import (2func main() {3    fmt.Println("Hello, playground")4    panic.Panic()5}6main.main()7import (8func main() {9    fmt.Println("Hello, playground")10    fmt.Panic()11}12main.main()13import (14func main() {15    fmt.Println("Hello, playground")16    fmt.Panic()17}18main.main()19import (20func main() {21    fmt.Println("Hello, playground")22    fmt.Panic()23}24main.main()

1import (2func main() {3    panic.PanicMethod()4}5import (6func main() {7    panic.PanicMethod()8}9import (10func main() {11    panic.PanicMethod()12}13import (14func main() {15    panic.PanicMethod()16}17import (18func main() {19    panic.PanicMethod()20}21import (22func main() {23    panic.PanicMethod()24}25import (26func main() {27    panic.PanicMethod()28}29import (30func main() {31    panic.PanicMethod()32}33import (34func main() {35    panic.PanicMethod()36}37import (38func main() {39    panic.PanicMethod()40}41import (

1import (2func main() {3    fmt.Println("Hello, playground")4    obj := internalclass.InternalClass{}5    obj.Panic()6}7import (8func main() {9    fmt.Println("Hello, playground")10    obj := internalclass.InternalClass{}11    obj.Panic()12}13import (14type InternalClass struct {15}16func (ic InternalClass) Panic() {17    panic("Panic in InternalClass")18    fmt.Println("Hello, playground")19}20import (21type InternalClass struct {22}23func (ic InternalClass) Panic() {24    panic("Panic in InternalClass")25    fmt.Println("Hello, playground")26}27import (28type InternalClass struct {29}30func (ic InternalClass) Panic() {31    panic("Panic in InternalClass")32    fmt.Println("Hello, playground")33}34import (35type InternalClass struct {36}37func (ic InternalClass) Panic() {38    panic("Panic in InternalClass")39    fmt.Println("Hello, playground")40}41import (42type InternalClass struct {43}44func (ic InternalClass) Panic() {45    panic("Panic in InternalClass")46    fmt.Println("Hello, playground")47}48import (49type InternalClass struct {50}51func (ic InternalClass) Panic() {52    panic("Panic in InternalClass")53    fmt.Println("Hello, playground")54}55import (56type InternalClass struct {57}58func (ic InternalClass) Panic() {59    panic("Panic in InternalClass")60    fmt.Println("Hello, playground")61}62import (63type InternalClass struct {64}65func (ic InternalClass) Panic() {66    panic("Panic in InternalClass")67    fmt.Println("Hello, playground")68}69import (70type InternalClass struct {71}72func (ic InternalClass) Panic() {73    panic("Panic in Internal

1import (2func main() {3    fmt.Println("Hello, playground")4    _2.Panic()5}6import (7func Panic() {8    fmt.Println("Hello, playground")9    panic("Panic")10}11panic(0x4f0b40, 0xc82000a0c0)12_/home/ashish/GoLangTraining/1/2.Panic(0x0, 0x0)13main.main()