issue19658.go

     1  // run
     2  //go:build !nacl && !js && !wasip1 && !gccgo
     3  
     4  // Copyright 2017 The Go Authors. All rights reserved.
     5  // Use of this source code is governed by a BSD-style
     6  // license that can be found in the LICENSE file.
     7  
     8  // ensure that panic(x) where x is a numeric type displays a readable number
     9  package main
    10  
    11  import (
    12  	"bytes"
    13  	"fmt"
    14  	"io/ioutil"
    15  	"log"
    16  	"os"
    17  	"os/exec"
    18  	"path/filepath"
    19  )
    20  
    21  const fn = `
    22  package main
    23  
    24  import  "errors"
    25  type S struct {
    26  
    27  }
    28  func (s S) String() string {
    29  	return "s-stringer"
    30  }
    31  func main() {
    32   	_ = errors.New
    33    panic(%s(%s))
    34  }
    35  `
    36  
    37  func main() {
    38  	tempDir, err := ioutil.TempDir("", "")
    39  	if err != nil {
    40  		log.Fatal(err)
    41  	}
    42  	defer os.RemoveAll(tempDir)
    43  	tmpFile := filepath.Join(tempDir, "tmp.go")
    44  
    45  	for _, tc := range []struct {
    46  		Type   string
    47  		Input  string
    48  		Expect string
    49  	}{
    50  		{"", "nil", "panic: panic called with nil argument"},
    51  		{"errors.New", `"test"`, "panic: test"},
    52  		{"S", "S{}", "panic: s-stringer"},
    53  		{"byte", "8", "panic: 8"},
    54  		{"rune", "8", "panic: 8"},
    55  		{"int", "8", "panic: 8"},
    56  		{"int8", "8", "panic: 8"},
    57  		{"int16", "8", "panic: 8"},
    58  		{"int32", "8", "panic: 8"},
    59  		{"int64", "8", "panic: 8"},
    60  		{"uint", "8", "panic: 8"},
    61  		{"uint8", "8", "panic: 8"},
    62  		{"uint16", "8", "panic: 8"},
    63  		{"uint32", "8", "panic: 8"},
    64  		{"uint64", "8", "panic: 8"},
    65  		{"uintptr", "8", "panic: 8"},
    66  		{"bool", "true", "panic: true"},
    67  		{"complex64", "8 + 16i", "panic: (+8.000000e+000+1.600000e+001i)"},
    68  		{"complex128", "8+16i", "panic: (+8.000000e+000+1.600000e+001i)"},
    69  		{"string", `"test"`, "panic: test"}} {
    70  
    71  		b := bytes.Buffer{}
    72  		fmt.Fprintf(&b, fn, tc.Type, tc.Input)
    73  
    74  		err = ioutil.WriteFile(tmpFile, b.Bytes(), 0644)
    75  		if err != nil {
    76  			log.Fatal(err)
    77  		}
    78  
    79  		cmd := exec.Command("go", "run", tmpFile)
    80  		var buf bytes.Buffer
    81  		cmd.Stdout = &buf
    82  		cmd.Stderr = &buf
    83  		cmd.Env = os.Environ()
    84  		cmd.Run() // ignore err as we expect a panic
    85  
    86  		out := buf.Bytes()
    87  		panicIdx := bytes.Index(out, []byte("panic: "))
    88  		if panicIdx == -1 {
    89  			log.Fatalf("expected a panic in output for %s, got: %s", tc.Type, out)
    90  		}
    91  		eolIdx := bytes.IndexByte(out[panicIdx:], '\n') + panicIdx
    92  		if panicIdx == -1 {
    93  			log.Fatalf("expected a newline in output for %s after the panic, got: %s", tc.Type, out)
    94  		}
    95  		out = out[0:eolIdx]
    96  		if string(out) != tc.Expect {
    97  			log.Fatalf("expected '%s' for panic(%s(%s)), got %s", tc.Expect, tc.Type, tc.Input, out)
    98  		}
    99  	}
   100  }
   101
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