issue26411.go

     1  // run
     2  
     3  //go:build !nacl && !js && !wasip1
     4  
     5  // Copyright 2018 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 label redefinition errors print out
    10  // a column number that matches the start of the current label's
    11  // definition instead of the label delimiting token ":"
    12  
    13  package main
    14  
    15  import (
    16  	"bytes"
    17  	"fmt"
    18  	"io/ioutil"
    19  	"log"
    20  	"os"
    21  	"os/exec"
    22  	"path/filepath"
    23  	"regexp"
    24  )
    25  
    26  func main() {
    27  	tmpdir, err := ioutil.TempDir("", "issue26411")
    28  	if err != nil {
    29  		log.Fatalf("Failed to create temporary directory: %v", err)
    30  	}
    31  	defer os.RemoveAll(tmpdir)
    32  
    33  	tests := []struct {
    34  		code   string
    35  		errors []string
    36  	}{
    37  		{
    38  			code: `
    39  package main
    40  
    41  func main() {
    42  foo:
    43  foo:
    44  }
    45  `,
    46  			errors: []string{
    47  				"^.+:5:1: label foo defined and not used\n",
    48  				".+:6:1: label foo already defined at .+:5:1\n$",
    49  			},
    50  		},
    51  		{
    52  			code: `
    53  package main
    54  
    55  func main() {
    56  
    57              bar:
    58     bar:
    59  bar:
    60  bar            :
    61  }
    62  `,
    63  
    64  			errors: []string{
    65  				"^.+:6:13: label bar defined and not used\n",
    66  				".+:7:4: label bar already defined at .+:6:13\n",
    67  				".+:8:1: label bar already defined at .+:6:13\n",
    68  				".+:9:1: label bar already defined at .+:6:13\n$",
    69  			},
    70  		},
    71  	}
    72  
    73  	for i, test := range tests {
    74  		filename := filepath.Join(tmpdir, fmt.Sprintf("%d.go", i))
    75  		if err := ioutil.WriteFile(filename, []byte(test.code), 0644); err != nil {
    76  			log.Printf("#%d: failed to create file %s", i, filename)
    77  			continue
    78  		}
    79  		output, _ := exec.Command("go", "tool", "compile", "-p=p", filename).CombinedOutput()
    80  
    81  		// remove each matching error from the output
    82  		for _, err := range test.errors {
    83  			rx := regexp.MustCompile(err)
    84  			match := rx.Find(output)
    85  			output = bytes.Replace(output, match, nil, 1) // remove match (which might be nil) from output
    86  		}
    87  
    88  		// at this point all output should have been consumed
    89  		if len(output) != 0 {
    90  			log.Printf("Test case %d has unmatched errors:\n%s", i, output)
    91  		}
    92  	}
    93  }
    94
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