libgo/go/cmd/vet/vet_test.go - gofrontend - Git at Google

 // Copyright 2013 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_test

 import (
 	"bytes"
 	"errors"
 	"fmt"
 	"internal/testenv"
 	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
 	"path"
 	"path/filepath"
 	"regexp"
 	"runtime"
 	"strconv"
 	"strings"
 	"sync"
 	"testing"
 )

 const dataDir = "testdata"

 var binary string

 // We implement TestMain so remove the test binary when all is done.
 func TestMain(m *testing.M) {
 	os.Exit(testMain(m))
 }

 func testMain(m *testing.M) int {
 	dir, err := ioutil.TempDir("", "vet_test")
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		return 1
 	}
 	defer os.RemoveAll(dir)
 	binary = filepath.Join(dir, "testvet.exe")

 	return m.Run()
 }

 var (
 	buildMu sync.Mutex // guards following
 	built   = false    // We have built the binary.
 	failed  = false    // We have failed to build the binary, don't try again.
 )

 func Build(t *testing.T) {
 	buildMu.Lock()
 	defer buildMu.Unlock()
 	if built {
 		return
 	}
 	if failed {
 		t.Skip("cannot run on this environment")
 	}
 	testenv.MustHaveGoBuild(t)
 	cmd := exec.Command(testenv.GoToolPath(t), "build", "-o", binary)
 	output, err := cmd.CombinedOutput()
 	if err != nil {
 		failed = true
 		fmt.Fprintf(os.Stderr, "%s\n", output)
 		t.Fatal(err)
 	}
 	built = true
 }

 func vetCmd(t *testing.T, arg, pkg string) *exec.Cmd {
 	cmd := exec.Command(testenv.GoToolPath(t), "vet", "-vettool="+binary, arg, path.Join("cmd/vet/testdata", pkg))
 	cmd.Env = os.Environ()
 	return cmd
 }

 func TestVet(t *testing.T) {
 	t.Parallel()
 	Build(t)
 	for _, pkg := range []string{
 		"asm",
 		"assign",
 		"atomic",
 		"bool",
 		"buildtag",
 		"cgo",
 		"composite",
 		"copylock",
 		"deadcode",
 		"httpresponse",
 		"lostcancel",
 		"method",
 		"nilfunc",
 		"print",
 		"rangeloop",
 		"shift",
 		"structtag",
 		"testingpkg",
 		// "testtag" has its own test
 		"unmarshal",
 		"unsafeptr",
 		"unused",
 	} {
 		pkg := pkg
 		t.Run(pkg, func(t *testing.T) {
 			t.Parallel()

 			// Skip cgo test on platforms without cgo.
 			if pkg == "cgo" && !cgoEnabled(t) {
 				return
 			}

 			cmd := vetCmd(t, "-printfuncs=Warn,Warnf", pkg)

 			// The asm test assumes amd64.
 			if pkg == "asm" {
 				if runtime.Compiler == "gccgo" {
 					t.Skip("asm test assumes gc")
 				}
 				cmd.Env = append(cmd.Env, "GOOS=linux", "GOARCH=amd64")
 			}

 			dir := filepath.Join("testdata", pkg)
 			gos, err := filepath.Glob(filepath.Join(dir, "*.go"))
 			if err != nil {
 				t.Fatal(err)
 			}
 			asms, err := filepath.Glob(filepath.Join(dir, "*.s"))
 			if err != nil {
 				t.Fatal(err)
 			}
 			var files []string
 			files = append(files, gos...)
 			files = append(files, asms...)

 			errchk(cmd, files, t)
 		})
 	}
 }

 func cgoEnabled(t *testing.T) bool {
 	// Don't trust build.Default.CgoEnabled as it is false for
 	// cross-builds unless CGO_ENABLED is explicitly specified.
 	// That's fine for the builders, but causes commands like
 	// 'GOARCH=386 go test .' to fail.
 	// Instead, we ask the go command.
 	cmd := exec.Command(testenv.GoToolPath(t), "list", "-f", "{{context.CgoEnabled}}")
 	out, _ := cmd.CombinedOutput()
 	return string(out) == "true\n"
 }

 func errchk(c *exec.Cmd, files []string, t *testing.T) {
 	output, err := c.CombinedOutput()
 	if _, ok := err.(*exec.ExitError); !ok {
 		t.Logf("vet output:\n%s", output)
 		t.Fatal(err)
 	}
 	fullshort := make([]string, 0, len(files)*2)
 	for _, f := range files {
 		fullshort = append(fullshort, f, filepath.Base(f))
 	}
 	err = errorCheck(string(output), false, fullshort...)
 	if err != nil {
 		t.Errorf("error check failed: %s", err)
 	}
 }

 // TestTags verifies that the -tags argument controls which files to check.
 func TestTags(t *testing.T) {
 	t.Parallel()
 	Build(t)
 	for tag, wantFile := range map[string]int{
 		"testtag":     1, // file1
 		"x testtag y": 1,
 		"othertag":    2,
 	} {
 		tag, wantFile := tag, wantFile
 		t.Run(tag, func(t *testing.T) {
 			t.Parallel()
 			t.Logf("-tags=%s", tag)
 			cmd := vetCmd(t, "-tags="+tag, "tagtest")
 			output, err := cmd.CombinedOutput()

 			want := fmt.Sprintf("file%d.go", wantFile)
 			dontwant := fmt.Sprintf("file%d.go", 3-wantFile)

 			// file1 has testtag and file2 has !testtag.
 			if !bytes.Contains(output, []byte(filepath.Join("tagtest", want))) {
 				t.Errorf("%s: %s was excluded, should be included", tag, want)
 			}
 			if bytes.Contains(output, []byte(filepath.Join("tagtest", dontwant))) {
 				t.Errorf("%s: %s was included, should be excluded", tag, dontwant)
 			}
 			if t.Failed() {
 				t.Logf("err=%s, output=<<%s>>", err, output)
 			}
 		})
 	}
 }

 // All declarations below were adapted from test/run.go.

 // errorCheck matches errors in outStr against comments in source files.
 // For each line of the source files which should generate an error,
 // there should be a comment of the form // ERROR "regexp".
 // If outStr has an error for a line which has no such comment,
 // this function will report an error.
 // Likewise if outStr does not have an error for a line which has a comment,
 // or if the error message does not match the <regexp>.
 // The <regexp> syntax is Perl but it's best to stick to egrep.
 //
 // Sources files are supplied as fullshort slice.
 // It consists of pairs: full path to source file and its base name.
 func errorCheck(outStr string, wantAuto bool, fullshort ...string) (err error) {
 	var errs []error
 	out := splitOutput(outStr, wantAuto)
 	// Cut directory name.
 	for i := range out {
 		for j := 0; j < len(fullshort); j += 2 {
 			full, short := fullshort[j], fullshort[j+1]
 			out[i] = strings.ReplaceAll(out[i], full, short)
 		}
 	}

 	var want []wantedError
 	for j := 0; j < len(fullshort); j += 2 {
 		full, short := fullshort[j], fullshort[j+1]
 		want = append(want, wantedErrors(full, short)...)
 	}
 	for _, we := range want {
 		var errmsgs []string
 		if we.auto {
 			errmsgs, out = partitionStrings("<autogenerated>", out)
 		} else {
 			errmsgs, out = partitionStrings(we.prefix, out)
 		}
 		if len(errmsgs) == 0 {
 			errs = append(errs, fmt.Errorf("%s:%d: missing error %q", we.file, we.lineNum, we.reStr))
 			continue
 		}
 		matched := false
 		n := len(out)
 		for _, errmsg := range errmsgs {
 			// Assume errmsg says "file:line: foo".
 			// Cut leading "file:line: " to avoid accidental matching of file name instead of message.
 			text := errmsg
 			if i := strings.Index(text, " "); i >= 0 {
 				text = text[i+1:]
 			}
 			if we.re.MatchString(text) {
 				matched = true
 			} else {
 				out = append(out, errmsg)
 			}
 		}
 		if !matched {
 			errs = append(errs, fmt.Errorf("%s:%d: no match for %#q in:\n\t%s", we.file, we.lineNum, we.reStr, strings.Join(out[n:], "\n\t")))
 			continue
 		}
 	}

 	if len(out) > 0 {
 		errs = append(errs, fmt.Errorf("Unmatched Errors:"))
 		for _, errLine := range out {
 			errs = append(errs, fmt.Errorf("%s", errLine))
 		}
 	}

 	if len(errs) == 0 {
 		return nil
 	}
 	if len(errs) == 1 {
 		return errs[0]
 	}
 	var buf bytes.Buffer
 	fmt.Fprintf(&buf, "\n")
 	for _, err := range errs {
 		fmt.Fprintf(&buf, "%s\n", err.Error())
 	}
 	return errors.New(buf.String())
 }

 func splitOutput(out string, wantAuto bool) []string {
 	// gc error messages continue onto additional lines with leading tabs.
 	// Split the output at the beginning of each line that doesn't begin with a tab.
 	// <autogenerated> lines are impossible to match so those are filtered out.
 	var res []string
 	for _, line := range strings.Split(out, "\n") {
 		line = strings.TrimSuffix(line, "\r") // normalize Windows output
 		if strings.HasPrefix(line, "\t") {
 			res[len(res)-1] += "\n" + line
 		} else if strings.HasPrefix(line, "go tool") || strings.HasPrefix(line, "#") || !wantAuto && strings.HasPrefix(line, "<autogenerated>") {
 			continue
 		} else if strings.TrimSpace(line) != "" {
 			res = append(res, line)
 		}
 	}
 	return res
 }

 // matchPrefix reports whether s starts with file name prefix followed by a :,
 // and possibly preceded by a directory name.
 func matchPrefix(s, prefix string) bool {
 	i := strings.Index(s, ":")
 	if i < 0 {
 		return false
 	}
 	j := strings.LastIndex(s[:i], "/")
 	s = s[j+1:]
 	if len(s) <= len(prefix) || s[:len(prefix)] != prefix {
 		return false
 	}
 	if s[len(prefix)] == ':' {
 		return true
 	}
 	return false
 }

 func partitionStrings(prefix string, strs []string) (matched, unmatched []string) {
 	for _, s := range strs {
 		if matchPrefix(s, prefix) {
 			matched = append(matched, s)
 		} else {
 			unmatched = append(unmatched, s)
 		}
 	}
 	return
 }

 type wantedError struct {
 	reStr   string
 	re      *regexp.Regexp
 	lineNum int
 	auto    bool // match <autogenerated> line
 	file    string
 	prefix  string
 }

 var (
 	errRx       = regexp.MustCompile(`// (?:GC_)?ERROR (.*)`)
 	errAutoRx   = regexp.MustCompile(`// (?:GC_)?ERRORAUTO (.*)`)
 	errQuotesRx = regexp.MustCompile(`"([^"]*)"`)
 	lineRx      = regexp.MustCompile(`LINE(([+-])([0-9]+))?`)
 )

 // wantedErrors parses expected errors from comments in a file.
 func wantedErrors(file, short string) (errs []wantedError) {
 	cache := make(map[string]*regexp.Regexp)

 	src, err := ioutil.ReadFile(file)
 	if err != nil {
 		log.Fatal(err)
 	}
 	for i, line := range strings.Split(string(src), "\n") {
 		lineNum := i + 1
 		if strings.Contains(line, "////") {
 			// double comment disables ERROR
 			continue
 		}
 		var auto bool
 		m := errAutoRx.FindStringSubmatch(line)
 		if m != nil {
 			auto = true
 		} else {
 			m = errRx.FindStringSubmatch(line)
 		}
 		if m == nil {
 			continue
 		}
 		all := m[1]
 		mm := errQuotesRx.FindAllStringSubmatch(all, -1)
 		if mm == nil {
 			log.Fatalf("%s:%d: invalid errchk line: %s", file, lineNum, line)
 		}
 		for _, m := range mm {
 			replacedOnce := false
 			rx := lineRx.ReplaceAllStringFunc(m[1], func(m string) string {
 				if replacedOnce {
 					return m
 				}
 				replacedOnce = true
 				n := lineNum
 				if strings.HasPrefix(m, "LINE+") {
 					delta, _ := strconv.Atoi(m[5:])
 					n += delta
 				} else if strings.HasPrefix(m, "LINE-") {
 					delta, _ := strconv.Atoi(m[5:])
 					n -= delta
 				}
 				return fmt.Sprintf("%s:%d", short, n)
 			})
 			re := cache[rx]
 			if re == nil {
 				var err error
 				re, err = regexp.Compile(rx)
 				if err != nil {
 					log.Fatalf("%s:%d: invalid regexp \"%#q\" in ERROR line: %v", file, lineNum, rx, err)
 				}
 				cache[rx] = re
 			}
 			prefix := fmt.Sprintf("%s:%d", short, lineNum)
 			errs = append(errs, wantedError{
 				reStr:   rx,
 				re:      re,
 				prefix:  prefix,
 				auto:    auto,
 				lineNum: lineNum,
 				file:    short,
 			})
 		}
 	}

 	return
 }
	// Copyright 2013 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_test

	import (
	"bytes"
	"errors"
	"fmt"
	"internal/testenv"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"path"
	"path/filepath"
	"regexp"
	"runtime"
	"strconv"
	"strings"
	"sync"
	"testing"
	)

	const dataDir = "testdata"

	var binary string

	// We implement TestMain so remove the test binary when all is done.
	func TestMain(m *testing.M) {
	os.Exit(testMain(m))
	}

	func testMain(m *testing.M) int {
	dir, err := ioutil.TempDir("", "vet_test")
	if err != nil {
	fmt.Fprintln(os.Stderr, err)
	return 1
	}
	defer os.RemoveAll(dir)
	binary = filepath.Join(dir, "testvet.exe")

	return m.Run()
	}

	var (
	buildMu sync.Mutex // guards following
	built = false // We have built the binary.
	failed = false // We have failed to build the binary, don't try again.
	)

	func Build(t *testing.T) {
	buildMu.Lock()
	defer buildMu.Unlock()
	if built {
	return
	}
	if failed {
	t.Skip("cannot run on this environment")
	}
	testenv.MustHaveGoBuild(t)
	cmd := exec.Command(testenv.GoToolPath(t), "build", "-o", binary)
	output, err := cmd.CombinedOutput()
	if err != nil {
	failed = true
	fmt.Fprintf(os.Stderr, "%s\n", output)
	t.Fatal(err)
	}
	built = true
	}

	func vetCmd(t testing.T, arg, pkg string) exec.Cmd {
	cmd := exec.Command(testenv.GoToolPath(t), "vet", "-vettool="+binary, arg, path.Join("cmd/vet/testdata", pkg))
	cmd.Env = os.Environ()
	return cmd
	}

	func TestVet(t *testing.T) {
	t.Parallel()
	Build(t)
	for _, pkg := range []string{
	"asm",
	"assign",
	"atomic",
	"bool",
	"buildtag",
	"cgo",
	"composite",
	"copylock",
	"deadcode",
	"httpresponse",
	"lostcancel",
	"method",
	"nilfunc",
	"print",
	"rangeloop",
	"shift",
	"structtag",
	"testingpkg",
	// "testtag" has its own test
	"unmarshal",
	"unsafeptr",
	"unused",
	} {
	pkg := pkg
	t.Run(pkg, func(t *testing.T) {
	t.Parallel()

	// Skip cgo test on platforms without cgo.
	if pkg == "cgo" && !cgoEnabled(t) {
	return
	}

	cmd := vetCmd(t, "-printfuncs=Warn,Warnf", pkg)

	// The asm test assumes amd64.
	if pkg == "asm" {
	if runtime.Compiler == "gccgo" {
	t.Skip("asm test assumes gc")
	}
	cmd.Env = append(cmd.Env, "GOOS=linux", "GOARCH=amd64")
	}

	dir := filepath.Join("testdata", pkg)
	gos, err := filepath.Glob(filepath.Join(dir, "*.go"))
	if err != nil {
	t.Fatal(err)
	}
	asms, err := filepath.Glob(filepath.Join(dir, "*.s"))
	if err != nil {
	t.Fatal(err)
	}
	var files []string
	files = append(files, gos...)
	files = append(files, asms...)

	errchk(cmd, files, t)
	})
	}
	}

	func cgoEnabled(t *testing.T) bool {
	// Don't trust build.Default.CgoEnabled as it is false for
	// cross-builds unless CGO_ENABLED is explicitly specified.
	// That's fine for the builders, but causes commands like
	// 'GOARCH=386 go test .' to fail.
	// Instead, we ask the go command.
	cmd := exec.Command(testenv.GoToolPath(t), "list", "-f", "{{context.CgoEnabled}}")
	out, _ := cmd.CombinedOutput()
	return string(out) == "true\n"
	}

	func errchk(c exec.Cmd, files []string, t testing.T) {
	output, err := c.CombinedOutput()
	if _, ok := err.(*exec.ExitError); !ok {
	t.Logf("vet output:\n%s", output)
	t.Fatal(err)
	}
	fullshort := make([]string, 0, len(files)*2)
	for _, f := range files {
	fullshort = append(fullshort, f, filepath.Base(f))
	}
	err = errorCheck(string(output), false, fullshort...)
	if err != nil {
	t.Errorf("error check failed: %s", err)
	}
	}

	// TestTags verifies that the -tags argument controls which files to check.
	func TestTags(t *testing.T) {
	t.Parallel()
	Build(t)
	for tag, wantFile := range map[string]int{
	"testtag": 1, // file1
	"x testtag y": 1,
	"othertag": 2,
	} {
	tag, wantFile := tag, wantFile
	t.Run(tag, func(t *testing.T) {
	t.Parallel()
	t.Logf("-tags=%s", tag)
	cmd := vetCmd(t, "-tags="+tag, "tagtest")
	output, err := cmd.CombinedOutput()

	want := fmt.Sprintf("file%d.go", wantFile)
	dontwant := fmt.Sprintf("file%d.go", 3-wantFile)

	// file1 has testtag and file2 has !testtag.
	if !bytes.Contains(output, []byte(filepath.Join("tagtest", want))) {
	t.Errorf("%s: %s was excluded, should be included", tag, want)
	}
	if bytes.Contains(output, []byte(filepath.Join("tagtest", dontwant))) {
	t.Errorf("%s: %s was included, should be excluded", tag, dontwant)
	}
	if t.Failed() {
	t.Logf("err=%s, output=<<%s>>", err, output)
	}
	})
	}
	}

	// All declarations below were adapted from test/run.go.

	// errorCheck matches errors in outStr against comments in source files.
	// For each line of the source files which should generate an error,
	// there should be a comment of the form // ERROR "regexp".
	// If outStr has an error for a line which has no such comment,
	// this function will report an error.
	// Likewise if outStr does not have an error for a line which has a comment,
	// or if the error message does not match the <regexp>.
	// The <regexp> syntax is Perl but it's best to stick to egrep.
	//
	// Sources files are supplied as fullshort slice.
	// It consists of pairs: full path to source file and its base name.
	func errorCheck(outStr string, wantAuto bool, fullshort ...string) (err error) {
	var errs []error
	out := splitOutput(outStr, wantAuto)
	// Cut directory name.
	for i := range out {
	for j := 0; j < len(fullshort); j += 2 {
	full, short := fullshort[j], fullshort[j+1]
	out[i] = strings.ReplaceAll(out[i], full, short)
	}
	}

	var want []wantedError
	for j := 0; j < len(fullshort); j += 2 {
	full, short := fullshort[j], fullshort[j+1]
	want = append(want, wantedErrors(full, short)...)
	}
	for _, we := range want {
	var errmsgs []string
	if we.auto {
	errmsgs, out = partitionStrings("<autogenerated>", out)
	} else {
	errmsgs, out = partitionStrings(we.prefix, out)
	}
	if len(errmsgs) == 0 {
	errs = append(errs, fmt.Errorf("%s:%d: missing error %q", we.file, we.lineNum, we.reStr))
	continue
	}
	matched := false
	n := len(out)
	for _, errmsg := range errmsgs {
	// Assume errmsg says "file:line: foo".
	// Cut leading "file:line: " to avoid accidental matching of file name instead of message.
	text := errmsg
	if i := strings.Index(text, " "); i >= 0 {
	text = text[i+1:]
	}
	if we.re.MatchString(text) {
	matched = true
	} else {
	out = append(out, errmsg)
	}
	}
	if !matched {
	errs = append(errs, fmt.Errorf("%s:%d: no match for %#q in:\n\t%s", we.file, we.lineNum, we.reStr, strings.Join(out[n:], "\n\t")))
	continue
	}
	}

	if len(out) > 0 {
	errs = append(errs, fmt.Errorf("Unmatched Errors:"))
	for _, errLine := range out {
	errs = append(errs, fmt.Errorf("%s", errLine))
	}
	}

	if len(errs) == 0 {
	return nil
	}
	if len(errs) == 1 {
	return errs[0]
	}
	var buf bytes.Buffer
	fmt.Fprintf(&buf, "\n")
	for _, err := range errs {
	fmt.Fprintf(&buf, "%s\n", err.Error())
	}
	return errors.New(buf.String())
	}

	func splitOutput(out string, wantAuto bool) []string {
	// gc error messages continue onto additional lines with leading tabs.
	// Split the output at the beginning of each line that doesn't begin with a tab.
	// <autogenerated> lines are impossible to match so those are filtered out.
	var res []string
	for _, line := range strings.Split(out, "\n") {
	line = strings.TrimSuffix(line, "\r") // normalize Windows output
	if strings.HasPrefix(line, "\t") {
	res[len(res)-1] += "\n" + line
	} else if strings.HasPrefix(line, "go tool") \|\| strings.HasPrefix(line, "#") \|\| !wantAuto && strings.HasPrefix(line, "<autogenerated>") {
	continue
	} else if strings.TrimSpace(line) != "" {
	res = append(res, line)
	}
	}
	return res
	}

	// matchPrefix reports whether s starts with file name prefix followed by a :,
	// and possibly preceded by a directory name.
	func matchPrefix(s, prefix string) bool {
	i := strings.Index(s, ":")
	if i < 0 {
	return false
	}
	j := strings.LastIndex(s[:i], "/")
	s = s[j+1:]
	if len(s) <= len(prefix) \|\| s[:len(prefix)] != prefix {
	return false
	}
	if s[len(prefix)] == ':' {
	return true
	}
	return false
	}

	func partitionStrings(prefix string, strs []string) (matched, unmatched []string) {
	for _, s := range strs {
	if matchPrefix(s, prefix) {
	matched = append(matched, s)
	} else {
	unmatched = append(unmatched, s)
	}
	}
	return
	}

	type wantedError struct {
	reStr string
	re *regexp.Regexp
	lineNum int
	auto bool // match <autogenerated> line
	file string
	prefix string
	}

	var (
	errRx = regexp.MustCompile(`// (?:GC_)?ERROR (.*)`)
	errAutoRx = regexp.MustCompile(`// (?:GC_)?ERRORAUTO (.*)`)
	errQuotesRx = regexp.MustCompile(`"([^"]*)"`)
	lineRx = regexp.MustCompile(`LINE(([+-])([0-9]+))?`)
	)

	// wantedErrors parses expected errors from comments in a file.
	func wantedErrors(file, short string) (errs []wantedError) {
	cache := make(map[string]*regexp.Regexp)

	src, err := ioutil.ReadFile(file)
	if err != nil {
	log.Fatal(err)
	}
	for i, line := range strings.Split(string(src), "\n") {
	lineNum := i + 1
	if strings.Contains(line, "////") {
	// double comment disables ERROR
	continue
	}
	var auto bool
	m := errAutoRx.FindStringSubmatch(line)
	if m != nil {
	auto = true
	} else {
	m = errRx.FindStringSubmatch(line)
	}
	if m == nil {
	continue
	}
	all := m[1]
	mm := errQuotesRx.FindAllStringSubmatch(all, -1)
	if mm == nil {
	log.Fatalf("%s:%d: invalid errchk line: %s", file, lineNum, line)
	}
	for _, m := range mm {
	replacedOnce := false
	rx := lineRx.ReplaceAllStringFunc(m[1], func(m string) string {
	if replacedOnce {
	return m
	}
	replacedOnce = true
	n := lineNum
	if strings.HasPrefix(m, "LINE+") {
	delta, _ := strconv.Atoi(m[5:])
	n += delta
	} else if strings.HasPrefix(m, "LINE-") {
	delta, _ := strconv.Atoi(m[5:])
	n -= delta
	}
	return fmt.Sprintf("%s:%d", short, n)
	})
	re := cache[rx]
	if re == nil {
	var err error
	re, err = regexp.Compile(rx)
	if err != nil {
	log.Fatalf("%s:%d: invalid regexp \"%#q\" in ERROR line: %v", file, lineNum, rx, err)
	}
	cache[rx] = re
	}
	prefix := fmt.Sprintf("%s:%d", short, lineNum)
	errs = append(errs, wantedError{
	reStr: rx,
	re: re,
	prefix: prefix,
	auto: auto,
	lineNum: lineNum,
	file: short,
	})
	}
	}

	return
	}