Deprecation of package ioutil in Go 1.16

ioutil.ReadFile(...) became -> os.ReadFile(...)

go-critic/go-critic#1019

altsrc/json_command_test.go

@@ -2,7 +2,6 @@ package altsrc
 
 import (
 	"flag"
-	"io/ioutil"
 	"os"
 	"testing"
 
@@ -318,7 +317,7 @@ func TestCommandJSONFileFlagHasDefaultGlobalEnvJSONSetGlobalEnvWinsNested(t *tes
 }
 
 func writeTempFile(t *testing.T, name string, content string) func() {
-	if err := ioutil.WriteFile(name, []byte(content), 0666); err != nil {
+	if err := os.WriteFile(name, []byte(content), 0666); err != nil {
 		t.Fatalf("cannot write %q: %v", name, err)
 	}
 	return func() {

altsrc/json_source_context.go

@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"strings"
 	"time"
 
@@ -40,7 +39,7 @@ func NewJSONSourceFromFile(f string) (InputSourceContext, error) {
 // NewJSONSourceFromReader returns an InputSourceContext suitable for
 // retrieving config variables from an io.Reader that returns JSON data.
 func NewJSONSourceFromReader(r io.Reader) (InputSourceContext, error) {
-	data, err := ioutil.ReadAll(r)
+	data, err := io.ReadAll(r)
 	if err != nil {
 		return nil, err
 	}

altsrc/toml_command_test.go

@@ -2,7 +2,6 @@ package altsrc
 
 import (
 	"flag"
-	"io/ioutil"
 	"os"
 	"testing"
 
@@ -12,7 +11,7 @@ import (
 func TestCommandTomFileTest(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.toml", []byte("test = 15"), 0666)
+	_ = os.WriteFile("current.toml", []byte("test = 15"), 0666)
 	defer os.Remove("current.toml")
 	test := []string{"test-cmd", "--load", "current.toml"}
 	_ = set.Parse(test)
@@ -42,7 +41,7 @@ func TestCommandTomFileTest(t *testing.T) {
 func TestCommandTomlFileTestGlobalEnvVarWins(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.toml", []byte("test = 15"), 0666)
+	_ = os.WriteFile("current.toml", []byte("test = 15"), 0666)
 	defer os.Remove("current.toml")
 
 	_ = os.Setenv("THE_TEST", "10")
@@ -76,7 +75,7 @@ func TestCommandTomlFileTestGlobalEnvVarWins(t *testing.T) {
 func TestCommandTomlFileTestGlobalEnvVarWinsNested(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.toml", []byte("[top]\ntest = 15"), 0666)
+	_ = os.WriteFile("current.toml", []byte("[top]\ntest = 15"), 0666)
 	defer os.Remove("current.toml")
 
 	_ = os.Setenv("THE_TEST", "10")
@@ -110,7 +109,7 @@ func TestCommandTomlFileTestGlobalEnvVarWinsNested(t *testing.T) {
 func TestCommandTomlFileTestSpecifiedFlagWins(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.toml", []byte("test = 15"), 0666)
+	_ = os.WriteFile("current.toml", []byte("test = 15"), 0666)
 	defer os.Remove("current.toml")
 
 	test := []string{"test-cmd", "--load", "current.toml", "--test", "7"}
@@ -142,7 +141,7 @@ func TestCommandTomlFileTestSpecifiedFlagWins(t *testing.T) {
 func TestCommandTomlFileTestSpecifiedFlagWinsNested(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.toml", []byte(`[top]
+	_ = os.WriteFile("current.toml", []byte(`[top]
   test = 15`), 0666)
 	defer os.Remove("current.toml")
 
@@ -175,7 +174,7 @@ func TestCommandTomlFileTestSpecifiedFlagWinsNested(t *testing.T) {
 func TestCommandTomlFileTestDefaultValueFileWins(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.toml", []byte("test = 15"), 0666)
+	_ = os.WriteFile("current.toml", []byte("test = 15"), 0666)
 	defer os.Remove("current.toml")
 
 	test := []string{"test-cmd", "--load", "current.toml"}
@@ -207,7 +206,7 @@ func TestCommandTomlFileTestDefaultValueFileWins(t *testing.T) {
 func TestCommandTomlFileTestDefaultValueFileWinsNested(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.toml", []byte("[top]\ntest = 15"), 0666)
+	_ = os.WriteFile("current.toml", []byte("[top]\ntest = 15"), 0666)
 	defer os.Remove("current.toml")
 
 	test := []string{"test-cmd", "--load", "current.toml"}
@@ -239,7 +238,7 @@ func TestCommandTomlFileTestDefaultValueFileWinsNested(t *testing.T) {
 func TestCommandTomlFileFlagHasDefaultGlobalEnvTomlSetGlobalEnvWins(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.toml", []byte("test = 15"), 0666)
+	_ = os.WriteFile("current.toml", []byte("test = 15"), 0666)
 	defer os.Remove("current.toml")
 
 	_ = os.Setenv("THE_TEST", "11")
@@ -273,7 +272,7 @@ func TestCommandTomlFileFlagHasDefaultGlobalEnvTomlSetGlobalEnvWins(t *testing.T
 func TestCommandTomlFileFlagHasDefaultGlobalEnvTomlSetGlobalEnvWinsNested(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.toml", []byte("[top]\ntest = 15"), 0666)
+	_ = os.WriteFile("current.toml", []byte("[top]\ntest = 15"), 0666)
 	defer os.Remove("current.toml")
 
 	_ = os.Setenv("THE_TEST", "11")

altsrc/yaml_command_test.go

@@ -2,7 +2,6 @@ package altsrc
 
 import (
 	"flag"
-	"io/ioutil"
 	"os"
 	"testing"
 
@@ -12,7 +11,7 @@ import (
 func TestCommandYamlFileTest(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.yaml", []byte("test: 15"), 0666)
+	_ = os.WriteFile("current.yaml", []byte("test: 15"), 0666)
 	defer os.Remove("current.yaml")
 	test := []string{"test-cmd", "--load", "current.yaml"}
 	_ = set.Parse(test)
@@ -42,7 +41,7 @@ func TestCommandYamlFileTest(t *testing.T) {
 func TestCommandYamlFileTestGlobalEnvVarWins(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.yaml", []byte("test: 15"), 0666)
+	_ = os.WriteFile("current.yaml", []byte("test: 15"), 0666)
 	defer os.Remove("current.yaml")
 
 	_ = os.Setenv("THE_TEST", "10")
@@ -76,7 +75,7 @@ func TestCommandYamlFileTestGlobalEnvVarWins(t *testing.T) {
 func TestCommandYamlFileTestGlobalEnvVarWinsNested(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.yaml", []byte(`top:
+	_ = os.WriteFile("current.yaml", []byte(`top:
   test: 15`), 0666)
 	defer os.Remove("current.yaml")
 
@@ -111,7 +110,7 @@ func TestCommandYamlFileTestGlobalEnvVarWinsNested(t *testing.T) {
 func TestCommandYamlFileTestSpecifiedFlagWins(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.yaml", []byte("test: 15"), 0666)
+	_ = os.WriteFile("current.yaml", []byte("test: 15"), 0666)
 	defer os.Remove("current.yaml")
 
 	test := []string{"test-cmd", "--load", "current.yaml", "--test", "7"}
@@ -143,7 +142,7 @@ func TestCommandYamlFileTestSpecifiedFlagWins(t *testing.T) {
 func TestCommandYamlFileTestSpecifiedFlagWinsNested(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.yaml", []byte(`top:
+	_ = os.WriteFile("current.yaml", []byte(`top:
   test: 15`), 0666)
 	defer os.Remove("current.yaml")
 
@@ -176,7 +175,7 @@ func TestCommandYamlFileTestSpecifiedFlagWinsNested(t *testing.T) {
 func TestCommandYamlFileTestDefaultValueFileWins(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.yaml", []byte("test: 15"), 0666)
+	_ = os.WriteFile("current.yaml", []byte("test: 15"), 0666)
 	defer os.Remove("current.yaml")
 
 	test := []string{"test-cmd", "--load", "current.yaml"}
@@ -208,7 +207,7 @@ func TestCommandYamlFileTestDefaultValueFileWins(t *testing.T) {
 func TestCommandYamlFileTestDefaultValueFileWinsNested(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.yaml", []byte(`top:
+	_ = os.WriteFile("current.yaml", []byte(`top:
   test: 15`), 0666)
 	defer os.Remove("current.yaml")
 
@@ -241,7 +240,7 @@ func TestCommandYamlFileTestDefaultValueFileWinsNested(t *testing.T) {
 func TestCommandYamlFileFlagHasDefaultGlobalEnvYamlSetGlobalEnvWins(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.yaml", []byte("test: 15"), 0666)
+	_ = os.WriteFile("current.yaml", []byte("test: 15"), 0666)
 	defer os.Remove("current.yaml")
 
 	_ = os.Setenv("THE_TEST", "11")
@@ -275,7 +274,7 @@ func TestCommandYamlFileFlagHasDefaultGlobalEnvYamlSetGlobalEnvWins(t *testing.T
 func TestCommandYamlFileFlagHasDefaultGlobalEnvYamlSetGlobalEnvWinsNested(t *testing.T) {
 	app := &cli.App{}
 	set := flag.NewFlagSet("test", 0)
-	_ = ioutil.WriteFile("current.yaml", []byte(`top:
+	_ = os.WriteFile("current.yaml", []byte(`top:
   test: 15`), 0666)
 	defer os.Remove("current.yaml")
 

altsrc/yaml_file_loader.go

@@ -2,7 +2,7 @@ package altsrc
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/url"
 	"os"
@@ -68,21 +68,21 @@ func loadDataFrom(filePath string) ([]byte, error) {
 			if err != nil {
 				return nil, err
 			}
-			return ioutil.ReadAll(res.Body)
+			return io.ReadAll(res.Body)
 		default:
 			return nil, fmt.Errorf("scheme of %s is unsupported", filePath)
 		}
 	} else if u.Path != "" { // i dont have a host, but I have a path. I am a local file.
 		if _, notFoundFileErr := os.Stat(filePath); notFoundFileErr != nil {
 			return nil, fmt.Errorf("Cannot read from file: '%s' because it does not exist.", filePath)
 		}
-		return ioutil.ReadFile(filePath)
+		return os.ReadFile(filePath)
 	} else if runtime.GOOS == "windows" && strings.Contains(u.String(), "\\") {
 		// on Windows systems u.Path is always empty, so we need to check the string directly.
 		if _, notFoundFileErr := os.Stat(filePath); notFoundFileErr != nil {
 			return nil, fmt.Errorf("Cannot read from file: '%s' because it does not exist.", filePath)
 		}
-		return ioutil.ReadFile(filePath)
+		return os.ReadFile(filePath)
 	}
 
 	return nil, fmt.Errorf("unable to determine how to load from path %s", filePath)

app_test.go

@@ -6,7 +6,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"reflect"
 	"strconv"
@@ -1278,7 +1277,7 @@ func TestApp_BeforeFunc(t *testing.T) {
 		Flags: []Flag{
 			&StringFlag{Name: "opt"},
 		},
-		Writer: ioutil.Discard,
+		Writer: io.Discard,
 	}
 
 	// run with the Before() func succeeding
@@ -1369,7 +1368,7 @@ func TestApp_BeforeAfterFuncShellCompletion(t *testing.T) {
 		Flags: []Flag{
 			&StringFlag{Name: "opt"},
 		},
-		Writer: ioutil.Discard,
+		Writer: io.Discard,
 	}
 
 	// run with the Before() func succeeding
@@ -1487,7 +1486,7 @@ func TestAppNoHelpFlag(t *testing.T) {
 
 	HelpFlag = nil
 
-	app := &App{Writer: ioutil.Discard}
+	app := &App{Writer: io.Discard}
 	err := app.Run([]string{"test", "-h"})
 
 	if err != flag.ErrHelp {
@@ -1718,7 +1717,7 @@ func TestApp_OrderOfOperations(t *testing.T) {
 			counts.OnUsageError = counts.Total
 			return errors.New("hay OnUsageError")
 		},
-		Writer: ioutil.Discard,
+		Writer: io.Discard,
 	}
 
 	beforeNoError := func(c *Context) error {
@@ -2308,7 +2307,7 @@ func TestApp_Run_DoesNotOverwriteErrorFromBefore(t *testing.T) {
 		Action: func(c *Context) error { return nil },
 		Before: func(c *Context) error { return fmt.Errorf("before error") },
 		After:  func(c *Context) error { return fmt.Errorf("after error") },
-		Writer: ioutil.Discard,
+		Writer: io.Discard,
 	}
 
 	err := app.Run([]string{"foo"})
@@ -2458,7 +2457,7 @@ func (c *customBoolFlag) IsSet() bool {
 func TestCustomFlagsUnused(t *testing.T) {
 	app := &App{
 		Flags:  []Flag{&customBoolFlag{"custom"}},
-		Writer: ioutil.Discard,
+		Writer: io.Discard,
 	}
 
 	err := app.Run([]string{"foo"})
@@ -2470,7 +2469,7 @@ func TestCustomFlagsUnused(t *testing.T) {
 func TestCustomFlagsUsed(t *testing.T) {
 	app := &App{
 		Flags:  []Flag{&customBoolFlag{"custom"}},
-		Writer: ioutil.Discard,
+		Writer: io.Discard,
 	}
 
 	err := app.Run([]string{"foo", "--custom=bar"})
@@ -2481,7 +2480,7 @@ func TestCustomFlagsUsed(t *testing.T) {
 
 func TestCustomHelpVersionFlags(t *testing.T) {
 	app := &App{
-		Writer: ioutil.Discard,
+		Writer: io.Discard,
 	}
 
 	// Be sure to reset the global flags
@@ -2573,7 +2572,7 @@ func TestShellCompletionForIncompleteFlags(t *testing.T) {
 		Action: func(ctx *Context) error {
 			return fmt.Errorf("should not get here")
 		},
-		Writer: ioutil.Discard,
+		Writer: io.Discard,
 	}
 	err := app.Run([]string{"", "--test-completion", "--" + "generate-bash-completion"})
 	if err != nil {
@@ -2636,7 +2635,7 @@ func TestWhenExitSubCommandWithCodeThenAppQuitUnexpectedly(t *testing.T) {
 
 func newTestApp() *App {
 	a := NewApp()
-	a.Writer = ioutil.Discard
+	a.Writer = io.Discard
 	return a
 }