issue52127.go

     1  // run
     2  
     3  //go:build !js && !wasip1
     4  
     5  // Copyright 2022 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  // Issue 52127: Too many syntax errors in many files can
    10  // cause deadlocks instead of displaying error messages
    11  // correctly.
    12  
    13  package main
    14  
    15  import (
    16  	"bytes"
    17  	"fmt"
    18  	"os"
    19  	"os/exec"
    20  	"path/filepath"
    21  )
    22  
    23  func main() {
    24  	dir, err := os.MkdirTemp("", "issue52127")
    25  	if err != nil {
    26  		panic(err)
    27  	}
    28  	defer os.RemoveAll(dir)
    29  
    30  	args := []string{"go", "build"}
    31  	write := func(prefix string, i int, data string) {
    32  		filename := filepath.Join(dir, fmt.Sprintf("%s%d.go", prefix, i))
    33  		if err := os.WriteFile(filename, []byte(data), 0o644); err != nil {
    34  			panic(err)
    35  		}
    36  		args = append(args, filename)
    37  	}
    38  
    39  	for i := 0; i < 100; i++ {
    40  		write("a", i, `package p
    41  `)
    42  	}
    43  	for i := 0; i < 100; i++ {
    44  		write("b", i, `package p
    45  var
    46  var
    47  var
    48  var
    49  var
    50  `)
    51  	}
    52  
    53  	cmd := exec.Command(args[0], args[1:]...)
    54  	output, err := cmd.CombinedOutput()
    55  	if err == nil {
    56  		panic("compile succeeded unexpectedly")
    57  	}
    58  	if !bytes.Contains(output, []byte("syntax error:")) {
    59  		panic(fmt.Sprintf(`missing "syntax error" in compiler output; got:
    60  %s`, output))
    61  	}
    62  }
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