refactor and reorganize core commands:

move `DetectSkipPostInstallValue` in arguments package
create `PostInstallFlags` struct in arguments package
remove `listFlags` struct

cli/arguments/post_install.go

+// This file is part of arduino-cli.
+//
+// Copyright 2020 ARDUINO SA (http://www.arduino.cc/)
+//
+// This software is released under the GNU General Public License version 3,
+// which covers the main part of arduino-cli.
+// The terms of this license can be found at:
+// https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to license@arduino.cc.
+
+package arguments
+
+import (
+	"github.com/arduino/arduino-cli/configuration"
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+// PostInstallFlags contains flags data used by the core install and the upgrade command
+// This is useful so all flags used by commands that need
+// this information are consistent with each other.
+type PostInstallFlags struct {
+	runPostInstall  bool // force the execution of installation scripts
+	skipPostInstall bool //skip the execution of installation scripts
+}
+
+// AddToCommand adds flags that can be used to force running or skipping
+// of post installation scripts
+func (p *PostInstallFlags) AddToCommand(cmd *cobra.Command) {
+	cmd.Flags().BoolVar(&p.runPostInstall, "run-post-install", false, tr("Force run of post-install scripts (if the CLI is not running interactively)."))
+	cmd.Flags().BoolVar(&p.skipPostInstall, "skip-post-install", false, tr("Force skip of post-install scripts (if the CLI is running interactively)."))
+}
+
+// GetRunPostInstall returns the run-post-install flag value
+func (p *PostInstallFlags) GetRunPostInstall() bool {
+	return p.runPostInstall
+}
+
+// GetSkipPostInstall returns the skip-post-install flag value
+func (p *PostInstallFlags) GetSkipPostInstall() bool {
+	return p.skipPostInstall
+}
+
+// DetectSkipPostInstallValue returns true if a post install script must be run
+func (p *PostInstallFlags) DetectSkipPostInstallValue() bool {
+	if p.GetRunPostInstall() {
+		logrus.Info("Will run post-install by user request")
+		return false
+	}
+	if p.GetSkipPostInstall() {
+		logrus.Info("Will skip post-install by user request")
+		return true
+	}
+
+	if !configuration.IsInteractive {
+		logrus.Info("Not running from console, will skip post-install by default")
+		return true
+	}
+	logrus.Info("Running from console, will run post-install by default")
+	return false
+}

cli/core/install.go

@@ -26,12 +26,15 @@ import (
 	"github.com/arduino/arduino-cli/cli/instance"
 	"github.com/arduino/arduino-cli/cli/output"
 	"github.com/arduino/arduino-cli/commands/core"
-	"github.com/arduino/arduino-cli/configuration"
 	rpc "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/commands/v1"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 )
 
+var (
+	postInstallFlags arguments.PostInstallFlags
+)
+
 func initInstallCommand() *cobra.Command {
 	installCommand := &cobra.Command{
 		Use:   fmt.Sprintf("install %s:%s[@%s]...", tr("PACKAGER"), tr("ARCH"), tr("VERSION")),
@@ -42,50 +45,18 @@ func initInstallCommand() *cobra.Command {
 			"  # " + tr("download a specific version (in this case 1.6.9).") + "\n" +
 			"  " + os.Args[0] + " core install arduino:samd@1.6.9",
 		Args: cobra.MinimumNArgs(1),
-		Run:  runInstallCommand,
+		PreRun: func(cmd *cobra.Command, args []string) {
+			arguments.CheckFlagsConflicts(cmd, "run-post-install", "skip-post-install")
+		},
+		Run: runInstallCommand,
 		ValidArgsFunction: func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
 			return arguments.GetInstallableCores(), cobra.ShellCompDirectiveDefault
 		},
 	}
-	AddPostInstallFlagsToCommand(installCommand)
+	postInstallFlags.AddToCommand(installCommand)
 	return installCommand
 }
 
-var postInstallFlags struct {
-	runPostInstall  bool
-	skipPostInstall bool
-}
-
-// AddPostInstallFlagsToCommand adds flags that can be used to force running or skipping
-// of post installation scripts
-func AddPostInstallFlagsToCommand(cmd *cobra.Command) {
-	cmd.Flags().BoolVar(&postInstallFlags.runPostInstall, "run-post-install", false, tr("Force run of post-install scripts (if the CLI is not running interactively)."))
-	cmd.Flags().BoolVar(&postInstallFlags.skipPostInstall, "skip-post-install", false, tr("Force skip of post-install scripts (if the CLI is running interactively)."))
-}
-
-// DetectSkipPostInstallValue returns true if a post install script must be run
-func DetectSkipPostInstallValue() bool {
-	if postInstallFlags.runPostInstall && postInstallFlags.skipPostInstall {
-		feedback.Errorf(tr("The flags --run-post-install and --skip-post-install can't be both set at the same time."))
-		os.Exit(errorcodes.ErrBadArgument)
-	}
-	if postInstallFlags.runPostInstall {
-		logrus.Info("Will run post-install by user request")
-		return false
-	}
-	if postInstallFlags.skipPostInstall {
-		logrus.Info("Will skip post-install by user request")
-		return true
-	}
-
-	if !configuration.IsInteractive {
-		logrus.Info("Not running from console, will skip post-install by default")
-		return true
-	}
-	logrus.Info("Running from console, will run post-install by default")
-	return false
-}
-
 func runInstallCommand(cmd *cobra.Command, args []string) {
 	inst := instance.CreateAndInit()
 	logrus.Info("Executing `arduino core install`")
@@ -102,7 +73,7 @@ func runInstallCommand(cmd *cobra.Command, args []string) {
 			PlatformPackage: platformRef.PackageName,
 			Architecture:    platformRef.Architecture,
 			Version:         platformRef.Version,
-			SkipPostInstall: DetectSkipPostInstallValue(),
+			SkipPostInstall: postInstallFlags.DetectSkipPostInstallValue(),
 		}
 		_, err := core.PlatformInstall(context.Background(), platformInstallRequest, output.ProgressBar(), output.TaskProgress())
 		if err != nil {

cli/core/list.go

@@ -29,6 +29,11 @@ import (
 	"github.com/spf13/cobra"
 )
 
+var (
+	updatableOnly bool
+	all           bool
+)
+
 func initListCommand() *cobra.Command {
 	listCommand := &cobra.Command{
 		Use:     "list",
@@ -38,24 +43,19 @@ func initListCommand() *cobra.Command {
 		Args:    cobra.NoArgs,
 		Run:     runListCommand,
 	}
-	listCommand.Flags().BoolVar(&listFlags.updatableOnly, "updatable", false, tr("List updatable platforms."))
-	listCommand.Flags().BoolVar(&listFlags.all, "all", false, tr("If set return all installable and installed cores, including manually installed."))
+	listCommand.Flags().BoolVar(&updatableOnly, "updatable", false, tr("List updatable platforms."))
+	listCommand.Flags().BoolVar(&all, "all", false, tr("If set return all installable and installed cores, including manually installed."))
 	return listCommand
 }
 
-var listFlags struct {
-	updatableOnly bool
-	all           bool
-}
-
 func runListCommand(cmd *cobra.Command, args []string) {
 	inst := instance.CreateAndInit()
 	logrus.Info("Executing `arduino core list`")
 
 	platforms, err := core.GetPlatforms(&rpc.PlatformListRequest{
 		Instance:      inst,
-		UpdatableOnly: listFlags.updatableOnly,
-		All:           listFlags.all,
+		UpdatableOnly: updatableOnly,
+		All:           all,
 	})
 	if err != nil {
 		feedback.Errorf(tr("Error listing platforms: %v"), err)

cli/core/upgrade.go

@@ -45,7 +45,7 @@ func initUpgradeCommand() *cobra.Command {
 			"  " + os.Args[0] + " core upgrade arduino:samd",
 		Run: runUpgradeCommand,
 	}
-	AddPostInstallFlagsToCommand(upgradeCommand)
+	postInstallFlags.AddToCommand(upgradeCommand)
 	return upgradeCommand
 }
 
@@ -93,7 +93,7 @@ func runUpgradeCommand(cmd *cobra.Command, args []string) {
 			Instance:        inst,
 			PlatformPackage: platformRef.PackageName,
 			Architecture:    platformRef.Architecture,
-			SkipPostInstall: DetectSkipPostInstallValue(),
+			SkipPostInstall: postInstallFlags.DetectSkipPostInstallValue(),
 		}
 
 		if _, err := core.PlatformUpgrade(context.Background(), r, output.ProgressBar(), output.TaskProgress()); err != nil {

cli/upgrade/upgrade.go

@@ -19,7 +19,7 @@ import (
 	"context"
 	"os"
 
-	"github.com/arduino/arduino-cli/cli/core"
+	"github.com/arduino/arduino-cli/cli/arguments"
 	"github.com/arduino/arduino-cli/cli/feedback"
 	"github.com/arduino/arduino-cli/cli/instance"
 	"github.com/arduino/arduino-cli/cli/output"
@@ -30,7 +30,10 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var tr = i18n.Tr
+var (
+	tr               = i18n.Tr
+	postInstallFlags arguments.PostInstallFlags
+)
 
 // NewCommand creates a new `upgrade` command
 func NewCommand() *cobra.Command {
@@ -43,7 +46,7 @@ func NewCommand() *cobra.Command {
 		Run:     runUpgradeCommand,
 	}
 
-	core.AddPostInstallFlagsToCommand(upgradeCommand)
+	postInstallFlags.AddToCommand(upgradeCommand)
 	return upgradeCommand
 }
 
@@ -53,7 +56,7 @@ func runUpgradeCommand(cmd *cobra.Command, args []string) {
 
 	err := commands.Upgrade(context.Background(), &rpc.UpgradeRequest{
 		Instance:        inst,
-		SkipPostInstall: core.DetectSkipPostInstallValue(),
+		SkipPostInstall: postInstallFlags.DetectSkipPostInstallValue(),
 	}, output.NewDownloadProgressBarCB(), output.TaskProgress())
 
 	if err != nil {