issue46234.go

     1  // buildrun -t 45
     2  
     3  //go:build !js && !wasip1
     4  
     5  // Copyright 2021 The Go Authors. All rights reserved.
     6  // Use of this source code is governed by a BSD-style
     7  // license that can be found in the LICENSE file.
     8  
     9  // Ensure that runtime traceback does not infinite loop for
    10  // the testcase below.
    11  
    12  package main
    13  
    14  import (
    15  	"bytes"
    16  	"io/ioutil"
    17  	"log"
    18  	"os"
    19  	"os/exec"
    20  	"path/filepath"
    21  )
    22  
    23  const prog = `
    24  
    25  package main
    26  
    27  import "context"
    28  
    29  var gpi *int
    30  
    31  type nAO struct {
    32  	eE bool
    33  }
    34  
    35  type NAO func(*nAO)
    36  
    37  func WEA() NAO {
    38  	return func(o *nAO) { o.eE = true }
    39  }
    40  
    41  type R struct {
    42  	cM *CM
    43  }
    44  
    45  type CM int
    46  
    47  type A string
    48  
    49  func (m *CM) NewA(ctx context.Context, cN string, nn *nAO, opts ...NAO) (*A, error) {
    50  	for _, o := range opts {
    51  		o(nn)
    52  	}
    53  	s := A("foo")
    54  	return &s, nil
    55  }
    56  
    57  func (r *R) CA(ctx context.Context, cN string, nn *nAO) (*int, error) {
    58  	cA, err := r.cM.NewA(ctx, cN, nn, WEA(), WEA())
    59  	if err == nil {
    60  		return nil, err
    61  	}
    62  	println(cA)
    63  	x := int(42)
    64  	return &x, nil
    65  }
    66  
    67  func main() {
    68  	c := CM(1)
    69  	r := R{cM: &c}
    70  	var ctx context.Context
    71  	nnr := nAO{}
    72  	pi, err := r.CA(ctx, "foo", nil)
    73  	if err != nil {
    74  		panic("bad")
    75  	}
    76  	println(nnr.eE)
    77  	gpi = pi
    78  }
    79  `
    80  
    81  func main() {
    82  	dir, err := ioutil.TempDir("", "46234")
    83  	if err != nil {
    84  		log.Fatal(err)
    85  	}
    86  	defer os.RemoveAll(dir)
    87  
    88  	file := filepath.Join(dir, "main.go")
    89  	if err := ioutil.WriteFile(file, []byte(prog), 0655); err != nil {
    90  		log.Fatalf("Write error %v", err)
    91  	}
    92  
    93  	cmd := exec.Command("go", "run", file)
    94  	output, err := cmd.CombinedOutput()
    95  	if err == nil {
    96  		log.Fatalf("Passed, expected an error")
    97  	}
    98  
    99  	want := []byte("nil pointer dereference")
   100  	if !bytes.Contains(output, want) {
   101  		log.Fatalf("Unmatched error message %q:\nin\n%s\nError: %v", want, output, err)
   102  	}
   103  }
   104
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