crash.go

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package main
     6  
     7  import (
     8  	"fmt"
     9  	"runtime"
    10  )
    11  
    12  func init() {
    13  	register("Crash", Crash)
    14  	register("DoublePanic", DoublePanic)
    15  	register("ErrorPanic", ErrorPanic)
    16  	register("StringerPanic", StringerPanic)
    17  	register("DoubleErrorPanic", DoubleErrorPanic)
    18  	register("DoubleStringerPanic", DoubleStringerPanic)
    19  	register("StringPanic", StringPanic)
    20  	register("NilPanic", NilPanic)
    21  	register("CircularPanic", CircularPanic)
    22  }
    23  
    24  func test(name string) {
    25  	defer func() {
    26  		if x := recover(); x != nil {
    27  			fmt.Printf(" recovered")
    28  		}
    29  		fmt.Printf(" done\n")
    30  	}()
    31  	fmt.Printf("%s:", name)
    32  	var s *string
    33  	_ = *s
    34  	fmt.Print("SHOULD NOT BE HERE")
    35  }
    36  
    37  func testInNewThread(name string) {
    38  	c := make(chan bool)
    39  	go func() {
    40  		runtime.LockOSThread()
    41  		test(name)
    42  		c <- true
    43  	}()
    44  	<-c
    45  }
    46  
    47  func Crash() {
    48  	runtime.LockOSThread()
    49  	test("main")
    50  	testInNewThread("new-thread")
    51  	testInNewThread("second-new-thread")
    52  	test("main-again")
    53  }
    54  
    55  type P string
    56  
    57  func (p P) String() string {
    58  	// Try to free the "YYY" string header when the "XXX"
    59  	// panic is stringified.
    60  	runtime.GC()
    61  	runtime.GC()
    62  	runtime.GC()
    63  	return string(p)
    64  }
    65  
    66  // Test that panic message is not clobbered.
    67  // See issue 30150.
    68  func DoublePanic() {
    69  	defer func() {
    70  		panic(P("YYY"))
    71  	}()
    72  	panic(P("XXX"))
    73  }
    74  
    75  // Test that panic while panicking discards error message
    76  // See issue 52257
    77  type exampleError struct{}
    78  
    79  func (e exampleError) Error() string {
    80  	panic("important error message")
    81  }
    82  
    83  func ErrorPanic() {
    84  	panic(exampleError{})
    85  }
    86  
    87  type examplePanicError struct{}
    88  
    89  func (e examplePanicError) Error() string {
    90  	panic(exampleError{})
    91  }
    92  
    93  func DoubleErrorPanic() {
    94  	panic(examplePanicError{})
    95  }
    96  
    97  type exampleStringer struct{}
    98  
    99  func (s exampleStringer) String() string {
   100  	panic("important stringer message")
   101  }
   102  
   103  func StringerPanic() {
   104  	panic(exampleStringer{})
   105  }
   106  
   107  type examplePanicStringer struct{}
   108  
   109  func (s examplePanicStringer) String() string {
   110  	panic(exampleStringer{})
   111  }
   112  
   113  func DoubleStringerPanic() {
   114  	panic(examplePanicStringer{})
   115  }
   116  
   117  func StringPanic() {
   118  	panic("important string message")
   119  }
   120  
   121  func NilPanic() {
   122  	panic(nil)
   123  }
   124  
   125  type exampleCircleStartError struct{}
   126  
   127  func (e exampleCircleStartError) Error() string {
   128  	panic(exampleCircleEndError{})
   129  }
   130  
   131  type exampleCircleEndError struct{}
   132  
   133  func (e exampleCircleEndError) Error() string {
   134  	panic(exampleCircleStartError{})
   135  }
   136  
   137  func CircularPanic() {
   138  	panic(exampleCircleStartError{})
   139  }
   140
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