analyzer/testdata: use \Q regexp quoting everywhere (#279)

In analysis test we're using `want` directive to match warnings.
I personally thing that 99% of time we need a string matching,
not a regexp matching. So this test checks that we do `\Q`
escaping everywhere, making our patterns matching string "as is";
so you don't have to escape `(` and `)` in the patterns.

analyzer/analyzer_test.go

@@ -4,10 +4,13 @@ import (
 	"bytes"
 	"fmt"
 	"go/token"
+	"io/fs"
 	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
+	"strings"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -42,6 +45,45 @@ var tests = []struct {
 	{name: "goversion", flags: map[string]string{"go": "1.16"}},
 }
 
+func TestDirectiveComments(t *testing.T) {
+	testdata := analysistest.TestData()
+	badDirectiveRe := regexp.MustCompile("// want `[^\\\\][^Q].*")
+	err := filepath.WalkDir(testdata, func(filename string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() {
+			return nil
+		}
+		if !strings.HasSuffix(filename, ".go") {
+			return nil
+		}
+		data, err := os.ReadFile(filename)
+		if err != nil {
+			return err
+		}
+		lines := bytes.Split(data, []byte("\n"))
+		for i, l := range lines {
+			m := badDirectiveRe.Find(l)
+			if m == nil {
+				continue
+			}
+			if bytes.HasPrefix(m, []byte("// want `true")) {
+				continue
+			}
+			if bytes.HasPrefix(m, []byte("// want `false")) {
+				continue
+			}
+			relName := strings.TrimPrefix(filename, filepath.Join(testdata, "src")+"/")
+			t.Errorf("%s:%d: escape 'want' text with \\Q in %s", relName, i+1, m)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
 func TestAnalyzer(t *testing.T) {
 	analyzer.ForceNewEngine = true
 	for i := range tests {

analyzer/testdata/src/comments/target.go

@@ -18,7 +18,7 @@ func f() {
 	//go:noinline
 	//go:generate foo bar
 
-	//nolint:gocritic // want `hey, this is kinda upsetting`
+	//nolint:gocritic // want `\Qhey, this is kinda upsetting`
 
 	// This is a begining // want `\Q"begining" may contain a typo`
 	// Of a bizzare text with typos. // want `\Q"bizzare" may contain a typo`

analyzer/testdata/src/comments/target_foo.go

@@ -1,3 +1,3 @@
 package comments
 
-//go:embed data.txt // want `don't use go:embed in _foo files`
+//go:embed data.txt // want `\Qdon't use go:embed in _foo files`

analyzer/testdata/src/dgryski/learngo.go

@@ -179,7 +179,7 @@ func learnFlowControl() {
 	}
 	// Use switch in preference to chained if statements.
 	x := 42.0
-	switch x { // want `floating point as switch expression`
+	switch x { // want `\Qfloating point as switch expression`
 	case 0:
 	case 1, 2: // Can have multiple matches on one case
 	case 42:

analyzer/testdata/src/extra/file.go

@@ -67,7 +67,7 @@ func testFormatBool() {
 
 func testBlankAssign() {
 	x := foo()
-	_ = x // want `please remove the assignment to _`
+	_ = x // want `\Qplease remove the assignment to _`
 
 	// This is OK, could be for side-effects.
 	_ = foo()
@@ -92,10 +92,10 @@ func nilErrCheck() {
 }
 
 func unparen(x, y int) {
-	if (x == 0) || (y == 0) { // want `rewrite as 'x == 0 || y == 0'`
+	if (x == 0) || (y == 0) { // want `\Qrewrite as 'x == 0 || y == 0'`
 	}
 
-	if (x != 5) && (y == 5) { // want `rewrite as 'x != 5 && y == 5'`
+	if (x != 5) && (y == 5) { // want `\Qrewrite as 'x != 5 && y == 5'`
 	}
 }
 
@@ -148,7 +148,7 @@ func makeExpr() {
 
 func chanRange() int {
 	ch := make(chan int)
-	for { // want `can use for range over ch`
+	for { // want `\Qcan use for range over ch`
 		select {
 		case c := <-ch:
 			return c
@@ -184,7 +184,7 @@ func argOrder() {
 
 func stringsReplace() {
 	var s string
-	_ = strings.Replace(s, " ", " ", -1) // want `replace 'old' and 'new' parameters are identical`
+	_ = strings.Replace(s, " ", " ", -1) // want `\Qreplace 'old' and 'new' parameters are identical`
 }
 
 func stringsRepeat() {
@@ -209,11 +209,11 @@ func stringsRepeat() {
 func stringsCompare() {
 	var s1, s2 string
 
-	_ = strings.Compare(s1, s2) == 0  // want `suggestion: s1 == s2`
-	_ = strings.Compare(s1, s2) < 0   // want `suggestion: s1 < s2`
-	_ = strings.Compare(s1, s2) == -1 // want `suggestion: s1 < s2`
-	_ = strings.Compare(s1, s2) > 0   // want `suggestion: s1 > s2`
-	_ = strings.Compare(s1, s2) == 1  // want `suggestion: s1 > s2`
+	_ = strings.Compare(s1, s2) == 0  // want `\Qsuggestion: s1 == s2`
+	_ = strings.Compare(s1, s2) < 0   // want `\Qsuggestion: s1 < s2`
+	_ = strings.Compare(s1, s2) == -1 // want `\Qsuggestion: s1 < s2`
+	_ = strings.Compare(s1, s2) > 0   // want `\Qsuggestion: s1 > s2`
+	_ = strings.Compare(s1, s2) == 1  // want `\Qsuggestion: s1 > s2`
 
 	if s1 == s2 {
 	}
@@ -298,7 +298,7 @@ func testCtx(ctx context.Context) error {
 	return nil
 }
 
-type errDontLog error // want `error as underlying type is probably a mistake`
+type errDontLog error // want `\Qerror as underlying type is probably a mistake`
 
 var ( // want `\Qempty var() block`
 // Empty decl...
@@ -436,8 +436,8 @@ func redundantLenCheck(xs []int, v int) {
 }
 
 func emptyError() {
-	_ = errors.New("") // want `empty error`
-	_ = errors.New(``) // want `empty error`
+	_ = errors.New("") // want `\Qempty error`
+	_ = errors.New(``) // want `\Qempty error`
 }
 
 func contextWithValue(ctx context.Context) {