golangci-lint: fix issues found by gosimple

Everything except the

	if err2.Err == syscall.EOPNOTSUPP

case. Gets too confusing when collapsed into a single line.

Issues were:

$ golangci-lint run --disable-all --enable gosimple
mount.go:473:2: S1008: should use 'return strings.HasPrefix(v, "fusermount version")' instead of 'if strings.HasPrefix(v, "fusermount version") { return true }; return false' (gosimple)
	if strings.HasPrefix(v, "fusermount version") {
	^
cli_args.go:258:5: S1002: should omit comparison to bool constant, can be simplified to `args.forcedecode` (gosimple)
	if args.forcedecode == true {
	   ^
cli_args.go:263:6: S1002: should omit comparison to bool constant, can be simplified to `args.aessiv` (gosimple)
		if args.aessiv == true {
		   ^
cli_args.go:267:6: S1002: should omit comparison to bool constant, can be simplified to `args.reverse` (gosimple)
		if args.reverse == true {
		   ^
internal/stupidgcm/stupidgcm.go:227:6: S1002: should omit comparison to bool constant, can be simplified to `g.forceDecode` (gosimple)
		if g.forceDecode == true {
		   ^
gocryptfs-xray/xray_tests/xray_test.go:23:5: S1004: should use !bytes.Equal(out, expected) instead (gosimple)
	if bytes.Compare(out, expected) != 0 {
	   ^
gocryptfs-xray/xray_tests/xray_test.go:40:5: S1004: should use !bytes.Equal(out, expected) instead (gosimple)
	if bytes.Compare(out, expected) != 0 {
	   ^
gocryptfs-xray/paths_ctlsock.go:34:20: S1002: should omit comparison to bool constant, can be simplified to `!eof` (gosimple)
	for eof := false; eof == false; line++ {
	                  ^
tests/reverse/xattr_test.go:19:2: S1008: should use 'return err2.Err != syscall.EOPNOTSUPP' instead of 'if err2.Err == syscall.EOPNOTSUPP { return false }; return true' (gosimple)
	if err2.Err == syscall.EOPNOTSUPP {
	^
internal/fusefrontend/node.go:459:45: S1002: should omit comparison to bool constant, can be simplified to `!nameFileAlreadyThere` (gosimple)
		if nametransform.IsLongContent(cName2) && nameFileAlreadyThere == false {
		                                          ^
tests/xattr/xattr_integration_test.go:221:2: S1008: should use 'return err2.Err != syscall.EOPNOTSUPP' instead of 'if err2.Err == syscall.EOPNOTSUPP { return false }; return true' (gosimple)
	if err2.Err == syscall.EOPNOTSUPP {
	^
tests/test_helpers/helpers.go:338:19: S1002: should omit comparison to bool constant, can be simplified to `open` (gosimple)
	if err != nil && open == true {
	                 ^
tests/matrix/concurrency_test.go:121:7: S1004: should use !bytes.Equal(buf, content) instead (gosimple)
			if bytes.Compare(buf, content) != 0 {
			   ^

cli_args.go

@@ -255,16 +255,16 @@ func parseCliOpts(osArgs []string) (args argContainer) {
 		}
 	}
 	// "-forcedecode" only works with openssl. Check compilation and command line parameters
-	if args.forcedecode == true {
-		if stupidgcm.BuiltWithoutOpenssl == true {
+	if args.forcedecode {
+		if stupidgcm.BuiltWithoutOpenssl {
 			tlog.Fatal.Printf("The -forcedecode flag requires openssl support, but gocryptfs was compiled without it!")
 			os.Exit(exitcodes.Usage)
 		}
-		if args.aessiv == true {
+		if args.aessiv {
 			tlog.Fatal.Printf("The -forcedecode and -aessiv flags are incompatible because they use different crypto libs (openssl vs native Go)")
 			os.Exit(exitcodes.Usage)
 		}
-		if args.reverse == true {
+		if args.reverse {
 			tlog.Fatal.Printf("The reverse mode and the -forcedecode option are not compatible")
 			os.Exit(exitcodes.Usage)
 		}

gocryptfs-xray/paths_ctlsock.go

@@ -31,7 +31,7 @@ func transformPaths(socketPath string, req *ctlsock.RequestStruct, in *string, s
 		separator = '\000'
 	}
 	r := bufio.NewReader(os.Stdin)
-	for eof := false; eof == false; line++ {
+	for eof := false; !eof; line++ {
 		val, err := r.ReadBytes(separator)
 		if len(val) == 0 {
 			break

gocryptfs-xray/xray_tests/xray_test.go

@@ -20,7 +20,7 @@ func TestAesgcmXray(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if bytes.Compare(out, expected) != 0 {
+	if !bytes.Equal(out, expected) {
 		t.Errorf("Unexpected output")
 		fmt.Printf("expected:\n%s", string(expected))
 		fmt.Printf("have:\n%s", string(out))
@@ -37,7 +37,7 @@ func TestAessivXray(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if bytes.Compare(out, expected) != 0 {
+	if !bytes.Equal(out, expected) {
 		t.Errorf("Unexpected output")
 		fmt.Printf("expected:\n%s", string(expected))
 		fmt.Printf("have:\n%s", string(out))

internal/fusefrontend/node.go

@@ -456,7 +456,7 @@ func (n *Node) Rename(ctx context.Context, name string, newParent fs.InodeEmbedd
 		}
 	}
 	if err != nil {
-		if nametransform.IsLongContent(cName2) && nameFileAlreadyThere == false {
+		if nametransform.IsLongContent(cName2) && !nameFileAlreadyThere {
 			// Roll back .name creation unless the .name file was already there
 			nametransform.DeleteLongNameAt(dirfd2, cName2)
 		}

internal/stupidgcm/stupidgcm.go

@@ -224,7 +224,7 @@ func (g *StupidGCM) Open(dst, iv, in, authData []byte) ([]byte, error) {
 	if res != 1 {
 		// The error code must always be checked by the calling function, because the decrypted buffer
 		// may contain corrupted data that we are returning in case the user forced reads
-		if g.forceDecode == true {
+		if g.forceDecode {
 			return append(dst, buf...), ErrAuth
 		}
 		return nil, ErrAuth

mount.go

@@ -470,10 +470,7 @@ func haveFusermount2() bool {
 	// libfuse 2: fusermount version: 2.9.9
 	// libfuse 3: fusermount3 version: 3.9.0
 	v := out.String()
-	if strings.HasPrefix(v, "fusermount version") {
-		return true
-	}
-	return false
+	return strings.HasPrefix(v, "fusermount version")
 }
 
 func handleSigint(srv *fuse.Server, mountpoint string) {

tests/matrix/concurrency_test.go

@@ -118,7 +118,7 @@ func TestConcurrentReadCreate(t *testing.T) {
 				log.Fatal(err)
 			}
 			buf := buf0[:n]
-			if bytes.Compare(buf, content) != 0 {
+			if !bytes.Equal(buf, content) {
 				// Calling t.Fatal() from a goroutine hangs the test so we use log.Fatal
 				log.Fatalf("%s: content mismatch: have=%q want=%q", t.Name(), string(buf), string(content))
 			}

tests/test_helpers/helpers.go

@@ -335,7 +335,7 @@ func VerifyExistence(t *testing.T, path string) bool {
 	dir := filepath.Dir(path)
 	name := filepath.Base(path)
 	d, err := os.Open(dir)
-	if err != nil && open == true {
+	if err != nil && open {
 		t.Errorf("VerifyExistence: we can open the file but not the parent dir!? err=%v", err)
 	} else if err == nil {
 		defer d.Close()