Fix lint errors and use error.Is instead of direct comparison

Author: cmaglie

Diff for: arduino/libraries/librariesmanager/install.go

@@ -31,16 +31,16 @@ import (
 	"gopkg.in/src-d/go-git.v4"
 )
 
-type AlreadyInstalledError struct{}
+type alreadyInstalledError struct{}
 
-func (e *AlreadyInstalledError) Error() string {
+func (e *alreadyInstalledError) Error() string {
 	return tr("library already installed")
 }
 
 var (
 	// ErrAlreadyInstalled is returned when a library is already installed and task
 	// cannot proceed.
-	ErrAlreadyInstalled = &AlreadyInstalledError{}
+	ErrAlreadyInstalled = &alreadyInstalledError{}
 )
 
 // InstallPrerequisiteCheck performs prequisite checks to install a library. It returns the

Diff for: commands/board/list.go

@@ -35,15 +35,15 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-type BoardNotFoundError struct{}
+type boardNotFoundError struct{}
 
-func (e *BoardNotFoundError) Error() string {
+func (e *boardNotFoundError) Error() string {
 	return tr("board not found")
 }
 
 var (
 	// ErrNotFound is returned when the API returns 404
-	ErrNotFound = &BoardNotFoundError{}
+	ErrNotFound = &boardNotFoundError{}
 	vidPidURL   = "https://builder.arduino.cc/v3/boards/byVidPid"
 	validVidPid = regexp.MustCompile(`0[xX][a-fA-F\d]{4}`)
 )
@@ -138,7 +138,7 @@ func identify(pm *packagemanager.PackageManager, port *discovery.Port) ([]*rpc.B
 	// the builder API if the board is a USB device port
 	if len(boards) == 0 {
 		items, err := identifyViaCloudAPI(port)
-		if err == ErrNotFound {
+		if errors.Is(err, ErrNotFound) {
 			// the board couldn't be detected, print a warning
 			logrus.Debug("Board not recognized")
 		} else if err != nil {

Diff for: commands/board/list_test.go

@@ -108,7 +108,7 @@ func TestBoardDetectionViaAPIWithNonUSBPort(t *testing.T) {
 		Properties: properties.NewMap(),
 	}
 	items, err := identifyViaCloudAPI(port)
-	require.Equal(t, err, ErrNotFound)
+	require.ErrorIs(t, err, ErrNotFound)
 	require.Empty(t, items)
 }
 

Diff for: commands/instances.go

@@ -17,6 +17,7 @@ package commands
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"net/url"
@@ -703,7 +704,7 @@ func Upgrade(ctx context.Context, req *rpc.UpgradeRequest, downloadCB DownloadPr
 			// Installs downloaded library
 			taskCB(&rpc.TaskProgress{Name: tr("Installing %s", available)})
 			libPath, libReplaced, err := lm.InstallPrerequisiteCheck(available)
-			if err == librariesmanager.ErrAlreadyInstalled {
+			if errors.Is(err, librariesmanager.ErrAlreadyInstalled) {
 				taskCB(&rpc.TaskProgress{Message: tr("Already installed %s", available), Completed: true})
 				continue
 			} else if err != nil {

Diff for: commands/lib/install.go

@@ -92,7 +92,7 @@ func installLibrary(lm *librariesmanager.LibrariesManager, libRelease *libraries
 	taskCB(&rpc.TaskProgress{Name: tr("Installing %s", libRelease)})
 	logrus.WithField("library", libRelease).Info("Installing library")
 	libPath, libReplaced, err := lm.InstallPrerequisiteCheck(libRelease)
-	if err == librariesmanager.ErrAlreadyInstalled {
+	if errors.Is(err, librariesmanager.ErrAlreadyInstalled) {
 		taskCB(&rpc.TaskProgress{Message: tr("Already installed %s", libRelease), Completed: true})
 		return nil
 	}