Move away from deprecated ioutils (#825)

Fix #806

Author: mgechev

config/config.go

@@ -3,7 +3,7 @@ package config
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"os"
 
 	"github.com/mgechev/revive/formatter"
 
@@ -140,7 +140,7 @@ func GetLintingRules(config *lint.Config, extraRules []lint.Rule) ([]lint.Rule,
 }
 
 func parseConfig(path string, config *lint.Config) error {
-	file, err := ioutil.ReadFile(path)
+	file, err := os.ReadFile(path)
 	if err != nil {
 		return errors.New("cannot read the config file")
 	}

logging/logger.go

@@ -2,7 +2,6 @@ package logging
 
 import (
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 )
@@ -27,7 +26,7 @@ func GetLogger() (*log.Logger, error) {
 		}
 	} else {
 		// Suppress all logging output if debug mode is disabled
-		writer = ioutil.Discard
+		writer = io.Discard
 	}
 
 	logger = log.New(writer, "", log.LstdFlags)

revivelib/core.go

@@ -1,8 +1,8 @@
 package revivelib
 
 import (
-	"io/ioutil"
 	"log"
+	"os"
 	"strings"
 
 	"github.com/mgechev/dots"
@@ -88,7 +88,7 @@ func (r *Revive) Lint(patterns ...*LintPattern) (<-chan lint.Failure, error) {
 	}
 
 	revive := lint.New(func(file string) ([]byte, error) {
-		contents, err := ioutil.ReadFile(file)
+		contents, err := os.ReadFile(file)
 
 		if err != nil {
 			return nil, errors.Wrap(err, "reading file "+file)

test/golint_test.go

@@ -2,7 +2,7 @@ package test
 
 import (
 	"flag"
-	"io/ioutil"
+	"os"
 	"path"
 	"regexp"
 	"testing"
@@ -41,9 +41,9 @@ func TestAll(t *testing.T) {
 		t.Fatalf("Bad -lint.match value %q: %v", *lintMatch, err)
 	}
 
-	fis, err := ioutil.ReadDir(baseDir)
+	fis, err := os.ReadDir(baseDir)
 	if err != nil {
-		t.Fatalf("ioutil.ReadDir: %v", err)
+		t.Fatalf("os.ReadDir: %v", err)
 	}
 	if len(fis) == 0 {
 		t.Fatalf("no files in %v", baseDir)
@@ -53,12 +53,18 @@ func TestAll(t *testing.T) {
 			continue
 		}
 		t.Run(fi.Name(), func(t *testing.T) {
-			src, err := ioutil.ReadFile(path.Join(baseDir, fi.Name()))
+			filePath := path.Join(baseDir, fi.Name())
+			src, err := os.ReadFile(filePath)
 			if err != nil {
 				t.Fatalf("Failed reading %s: %v", fi.Name(), err)
 			}
 
-			if err := assertFailures(t, baseDir, fi, src, rules, map[string]lint.RuleConfig{}); err != nil {
+			fileInfo, err := os.Stat(filePath)
+			if err != nil {
+				t.Fatalf("Failed reading %s: %v", fi.Name(), err)
+			}
+
+			if err := assertFailures(t, baseDir, fileInfo, src, rules, map[string]lint.RuleConfig{}); err != nil {
 				t.Errorf("Linting %s: %v", fi.Name(), err)
 			}
 		})

test/utils.go

@@ -8,7 +8,6 @@ import (
 	"go/parser"
 	"go/token"
 	"go/types"
-	"io/ioutil"
 	"os"
 	"strconv"
 	"strings"
@@ -21,7 +20,7 @@ import (
 func testRule(t *testing.T, filename string, rule lint.Rule, config ...*lint.RuleConfig) {
 	baseDir := "../testdata/"
 	filename = filename + ".go"
-	src, err := ioutil.ReadFile(baseDir + filename)
+	src, err := os.ReadFile(baseDir + filename)
 	if err != nil {
 		t.Fatalf("Bad filename path in test for %s: %v", rule.Name(), err)
 	}
@@ -42,7 +41,7 @@ func testRule(t *testing.T, filename string, rule lint.Rule, config ...*lint.Rul
 
 func assertSuccess(t *testing.T, baseDir string, fi os.FileInfo, rules []lint.Rule, config map[string]lint.RuleConfig) error {
 	l := lint.New(func(file string) ([]byte, error) {
-		return ioutil.ReadFile(baseDir + file)
+		return os.ReadFile(baseDir + file)
 	}, 0)
 
 	ps, err := l.Lint([][]string{{fi.Name()}}, rules, lint.Config{
@@ -64,7 +63,7 @@ func assertSuccess(t *testing.T, baseDir string, fi os.FileInfo, rules []lint.Ru
 
 func assertFailures(t *testing.T, baseDir string, fi os.FileInfo, src []byte, rules []lint.Rule, config map[string]lint.RuleConfig) error {
 	l := lint.New(func(file string) ([]byte, error) {
-		return ioutil.ReadFile(baseDir + file)
+		return os.ReadFile(baseDir + file)
 	}, 0)
 
 	ins := parseInstructions(t, fi.Name(), src)

testdata/unused-param.go

@@ -3,7 +3,6 @@ package fixtures
 import (
 	"fmt"
 	"go/ast"
-	"io/ioutil"
 	"os"
 	"runtime"
 	"testing"
@@ -103,7 +102,7 @@ func getCompareFailCause(n *node, which int, prevValue string, prevIndex uint64)
 
 func assertSuccess(t *testing.T, baseDir string, fi os.FileInfo, src []byte, rules []lint.Rule, config map[string]lint.RuleConfig) error { // MATCH /parameter 'src' seems to be unused, consider removing or renaming it as _/
 	l := lint.New(func(file string) ([]byte, error) {
-		return ioutil.ReadFile(baseDir + file)
+		return os.ReadFile(baseDir + file)
 	})
 
 	ps, err := l.Lint([][]string{[]string{fi.Name()}}, rules, lint.Config{