Fix linter errors

This commit and others in this branch fix
the lint errors popping up in
#1400
to unblock this PR, to allow rebase other branches
to master without getting stuck on linter errors.

Changes
* Remove io.util usage from contentcache
* fix formatting issue in name.go
* fix formatting issue in type_cache.go
* add missing error-check in file_test.go
* remove reference to ioutil in auth.go
* remove reference to ioutil in proxy.go
* remove unnecessary assignment to blank identifier
* remove unnecessary int64 check vs maxInt64
* remove reference to deprecated io/ioutil
* add missing return-error-check

internal/auth/auth.go

@@ -17,7 +17,7 @@ package auth
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
+	"os"
 
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
@@ -31,7 +31,7 @@ func newTokenSourceFromPath(
 	scope string,
 ) (ts oauth2.TokenSource, err error) {
 	// Read the file.
-	contents, err := ioutil.ReadFile(path)
+	contents, err := os.ReadFile(path)
 	if err != nil {
 		err = fmt.Errorf("ReadFile(%q): %w", path, err)
 		return

internal/auth/proxy.go

@@ -19,7 +19,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"net/url"
@@ -75,7 +74,7 @@ func (ts proxyTokenSource) Token() (token *oauth2.Token, err error) {
 		return
 	}
 
-	body, err := ioutil.ReadAll(io.LimitReader(resp.Body, 1<<20))
+	body, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
 	if err != nil {
 		err = fmt.Errorf("proxyTokenSource cannot load body: %w", err)
 		return

internal/contentcache/contentcache.go

@@ -21,7 +21,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path"
 	"regexp"
@@ -83,7 +82,7 @@ func (c *ContentCache) WriteMetadataCheckpointFile(cacheFileName string, cacheFi
 		return
 	}
 	metadataFileName = fmt.Sprintf("%s.json", cacheFileName)
-	err = ioutil.WriteFile(metadataFileName, file, 0644)
+	err = os.WriteFile(metadataFileName, file, 0644)
 	if err != nil {
 		err = fmt.Errorf("WriteFile for JSON metadata: %w", err)
 		return
@@ -111,7 +110,7 @@ func (c *ContentCache) recoverFileFromCache(metadataFile fs.FileInfo) {
 	}
 	var metadata CacheFileObjectMetadata
 	metadataAbsolutePath := path.Join(c.tempDir, metadataFile.Name())
-	contents, err := ioutil.ReadFile(metadataAbsolutePath)
+	contents, err := os.ReadFile(metadataAbsolutePath)
 	if err != nil {
 		logger.Errorf("content cache: Skip metadata file %v due to read error: %s", metadataFile.Name(), err)
 		return
@@ -152,11 +151,20 @@ func (c *ContentCache) RecoverCache() error {
 		c.tempDir = "/tmp"
 	}
 	logger.Infof("Recovering cache:\n")
-	files, err := ioutil.ReadDir(c.tempDir)
+	dirEntries, err := os.ReadDir(c.tempDir)
 	if err != nil {
-		// if we fail to read the specified directory, log and return error
+		// if we fail to get the list of sub-directories
+		// in the temp directory, log and return error.
 		return fmt.Errorf("recover cache: %w", err)
 	}
+	files := make([]os.FileInfo, len(dirEntries))
+	for i, dirEntry := range dirEntries {
+		files[i], err = dirEntry.Info()
+		if err != nil {
+			// if we fail to read the specified directory, log and return error
+			return fmt.Errorf("recover cache: %w", err)
+		}
+	}
 	for _, metadataFile := range files {
 		c.recoverFileFromCache(metadataFile)
 	}
@@ -196,7 +204,7 @@ func (c *ContentCache) AddOrReplace(cacheObjectKey *CacheObjectKey, generation i
 		cacheObject.Destroy()
 	}
 	// Create a temporary cache file on disk
-	f, err := ioutil.TempFile(c.tempDir, CacheFilePrefix)
+	f, err := os.CreateTemp(c.tempDir, CacheFilePrefix)
 	if err != nil {
 		return nil, fmt.Errorf("TempFile: %w", err)
 	}

internal/fs/fs.go

@@ -594,7 +594,7 @@ func (fs *fileSystem) checkInvariants() {
 	//////////////////////////////////
 
 	// INVARIANT: For all keys k in handles, k < nextHandleID
-	for k, _ := range fs.handles {
+	for k := range fs.handles {
 		if k >= fs.nextHandleID {
 			panic(fmt.Sprintf("Illegal handle ID: %v", k))
 		}

internal/fs/inode/file_test.go

@@ -836,6 +836,7 @@ func (t *FileTest) TestSetMtimeForLocalFileShouldUpdateLocalFileAttributes() {
 	t.createInodeWithLocalParam("test", true)
 	createTime := t.in.mtimeClock.Now()
 	err = t.in.CreateEmptyTempFile()
+	AssertEq(nil, err)
 	// Validate the attributes on an empty file.
 	attrs, err = t.in.Attributes(t.ctx)
 	AssertEq(nil, err)

internal/fs/inode/name.go

@@ -20,8 +20,9 @@ import (
 )
 
 // Name is the inode's name that can be interpreted in 2 ways:
-//   (1) LocalName: the name of the inode in the local file system.
-//   (2) GcsObjectName: the name of its gcs object backed by the inode.
+//
+//	(1) LocalName: the name of the inode in the local file system.
+//	(2) GcsObjectName: the name of its gcs object backed by the inode.
 type Name struct {
 	// The value of bucketName can be:
 	// - "", when single gcs bucket is explicitly mounted for the file system.

internal/fs/inode/type_cache.go

@@ -28,10 +28,10 @@ type cacheEntry struct {
 // A cache that maps from a name to information about the type of the object
 // with that name. Each name N is in one of the following states:
 //
-//  *  Nothing is known about N.
-//  *  We have recorded that N is a file.
-//  *  We have recorded that N is a directory.
-//  *  We have recorded that N is both a file and a directory.
+//   - Nothing is known about N.
+//   - We have recorded that N is a file.
+//   - We have recorded that N is a directory.
+//   - We have recorded that N is both a file and a directory.
 //
 // Must be created with newTypeCache. May be contained in a larger struct.
 // External synchronization is required.

internal/gcsx/append_object_creator_test.go

@@ -17,7 +17,7 @@ package gcsx
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"strings"
 	"testing"
 	"time"
@@ -111,13 +111,14 @@ func (t *AppendObjectCreatorTest) CallsCreateObject() {
 		WillOnce(DoAll(SaveArg(1, &req), Return(nil, errors.New(""))))
 
 	// Call
-	t.call()
+	_, err := t.call()
+	AssertNe(nil, err)
 
 	AssertNe(nil, req)
 	ExpectTrue(strings.HasPrefix(req.Name, prefix), "Name: %s", req.Name)
 	ExpectThat(req.GenerationPrecondition, Pointee(Equals(0)))
 
-	b, err := ioutil.ReadAll(req.Contents)
+	b, err := io.ReadAll(req.Contents)
 	AssertEq(nil, err)
 	ExpectEq(t.srcContents, string(b))
 }
@@ -177,7 +178,8 @@ func (t *AppendObjectCreatorTest) CallsComposeObjects() {
 		WillOnce(Return(nil))
 
 	// Call
-	t.call()
+	_, err := t.call()
+	AssertNe(nil, err)
 
 	AssertNe(nil, req)
 	ExpectEq(t.srcObject.Name, req.DstName)

internal/gcsx/integration_test.go

@@ -19,7 +19,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"math"
 	"math/rand"
 	"strings"
 	"testing"
@@ -137,11 +136,6 @@ func (t *IntegrationTest) objectGeneration(name string) (gen int64) {
 		panic(err)
 	}
 
-	// Check the result.
-	if o.Generation > math.MaxInt64 {
-		panic(fmt.Sprintf("Out of range: %v", o.Generation))
-	}
-
 	gen = o.Generation
 	return
 }