test: eliminate use of Perl in fixedbugs/bug345.go

To allow testing of fixedbugs/bug345.go in Go,
a new flag -n is introduced. This flag disables setting
of relative path for local imports and imports search path
to current dir, namely -D . -I . are not passed to the compiler.
Error regexps are fixed to allow running the test in temp directory.

This change eliminates the last place where Perl
script "errchk" was used.

Fixes #25586.

Change-Id: If085f466e6955312d77315f96d3ef1cb68495aef
Reviewed-on: https://go-review.googlesource.com/115277
Run-TryBot: Yury Smolsky <yury@smolsky.by>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

test/fixedbugs/bug345.dir/main.go

@@ -6,8 +6,9 @@ package main
 
 import (
 	"bufio"
-	"./io"
 	goio "io"
+
+	"./io"
 )
 
 func main() {
@@ -22,7 +23,7 @@ func main() {
 	// main.go:27: cannot use &x (type *"io".SectionReader) as type *"/Users/rsc/g/go/test/fixedbugs/bug345.dir/io".SectionReader in function argument
 
 	var w io.Writer
-	bufio.NewWriter(w)  // ERROR "test/io|has incompatible type"
+	bufio.NewWriter(w) // ERROR "[\w.]+[^.]/io|has incompatible type"
 	var x goio.SectionReader
-	io.SR(&x)  // ERROR "test/io|has incompatible type"
+	io.SR(&x) // ERROR "[\w.]+[^.]/io|has incompatible type"
 }

test/fixedbugs/bug345.go

-// +build !nacl,!js,!plan9,!windows
-// run
+// errorcheckdir -n
 
+// run
 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package main
-
-import (
-	"fmt"
-	"os"
-	"os/exec"
-	"path/filepath"
-	"regexp"
-)
-
-func main() {
-	// TODO: If we get rid of errchk, re-enable this test on Plan 9 and Windows.
-	errchk, err := filepath.Abs("errchk")
-	check(err)
-
-	bugDir := filepath.Join(".", "fixedbugs", "bug345.dir")
-	run("go", "tool", "compile", filepath.Join(bugDir, "io.go"))
-	run(errchk, "go", "tool", "compile", "-e", filepath.Join(bugDir, "main.go"))
-
-	os.Remove("io.o")
-}
-
-var bugRE = regexp.MustCompile(`(?m)^BUG`)
-
-func run(name string, args ...string) {
-	cmd := exec.Command(name, args...)
-	out, err := cmd.CombinedOutput()
-	if bugRE.Match(out) || err != nil {
-		fmt.Println(string(out))
-		fmt.Println(err)
-		os.Exit(1)
-	}
-}
-
-func check(err error) {
-	if err != nil {
-		fmt.Println(err)
-		os.Exit(1)
-	}
-}
+package ignored

test/run.go

@@ -216,8 +216,12 @@ func compileFile(runcmd runCmd, longname string, flags []string) (out []byte, er
 	return runcmd(cmd...)
 }
 
-func compileInDir(runcmd runCmd, dir string, flags []string, names ...string) (out []byte, err error) {
-	cmd := []string{goTool(), "tool", "compile", "-e", "-D", ".", "-I", "."}
+func compileInDir(runcmd runCmd, dir string, flags []string, localImports bool, names ...string) (out []byte, err error) {
+	cmd := []string{goTool(), "tool", "compile", "-e"}
+	if localImports {
+		// Set relative path for local imports and import search path to current dir.
+		cmd = append(cmd, "-D", ".", "-I", ".")
+	}
 	cmd = append(cmd, flags...)
 	if *linkshared {
 		cmd = append(cmd, "-dynlink", "-installsuffix=dynlink")
@@ -489,6 +493,7 @@ func (t *test) run() {
 	wantError := false
 	wantAuto := false
 	singlefilepkgs := false
+	localImports := true
 	f := strings.Fields(action)
 	if len(f) > 0 {
 		action = f[0]
@@ -530,6 +535,12 @@ func (t *test) run() {
 			wantError = false
 		case "-s":
 			singlefilepkgs = true
+		case "-n":
+			// Do not set relative path for local imports to current dir,
+			// e.g. do not pass -D . -I . to the compiler.
+			// Used in fixedbugs/bug345.go to allow compilation and import of local pkg.
+			// See golang.org/issue/25635
+			localImports = false
 		case "-t": // timeout in seconds
 			args = args[1:]
 			var err error
@@ -668,7 +679,7 @@ func (t *test) run() {
 			return
 		}
 		for _, gofiles := range pkgs {
-			_, t.err = compileInDir(runcmd, longdir, flags, gofiles...)
+			_, t.err = compileInDir(runcmd, longdir, flags, localImports, gofiles...)
 			if t.err != nil {
 				return
 			}
@@ -690,7 +701,7 @@ func (t *test) run() {
 			errPkg--
 		}
 		for i, gofiles := range pkgs {
-			out, err := compileInDir(runcmd, longdir, flags, gofiles...)
+			out, err := compileInDir(runcmd, longdir, flags, localImports, gofiles...)
 			if i == errPkg {
 				if wantError && err == nil {
 					t.err = fmt.Errorf("compilation succeeded unexpectedly\n%s", out)
@@ -727,7 +738,7 @@ func (t *test) run() {
 			return
 		}
 		for i, gofiles := range pkgs {
-			_, err := compileInDir(runcmd, longdir, flags, gofiles...)
+			_, err := compileInDir(runcmd, longdir, flags, localImports, gofiles...)
 			// Allow this package compilation fail based on conditions below;
 			// its errors were checked in previous case.
 			if err != nil && !(wantError && action == "errorcheckandrundir" && i == len(pkgs)-2) {