Fixed i18n early static initialization problem

#1425 (comment)

these particular strings are not correctly handled by the i18n package because
they are declared at package level before the call to i18n.Init(), and so are
just returned as-is.

Author: cmaglie

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

@@ -17,7 +17,6 @@ package librariesmanager
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"net/url"
 	"os"
@@ -32,10 +31,16 @@ import (
 	"gopkg.in/src-d/go-git.v4"
 )
 
+type AlreadyInstalledError struct{}
+
+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 = errors.New(tr("library already installed"))
+	ErrAlreadyInstalled = &AlreadyInstalledError{}
 )
 
 // InstallPrerequisiteCheck performs prequisite checks to install a library. It returns the

Diff for: cli/cli.go

@@ -75,7 +75,7 @@ func NewCommand() *cobra.Command {
 		PersistentPostRun: postRun,
 	}
 
-	arduinoCli.SetUsageTemplate(usageTemplate)
+	arduinoCli.SetUsageTemplate(getUsageTemplate())
 
 	createCliCommandTree(arduinoCli)
 

Diff for: cli/usage.go

@@ -19,20 +19,20 @@ import (
 	"github.com/arduino/arduino-cli/i18n"
 )
 
-// Declare ids used in usage
-var (
-	tr = i18n.Tr
-	_  = tr("Usage:")
-	_  = tr("Aliases:")
-	_  = tr("Examples:")
-	_  = tr("Available Commands:")
-	_  = tr("Flags:")
-	_  = tr("Global Flags:")
-	_  = tr("Additional help topics:")
-	_  = tr("Use %s for more information about a command.")
-)
-
-const usageTemplate = `{{tr "Usage:"}}{{if .Runnable}}
+var tr = i18n.Tr
+
+func getUsageTemplate() string {
+	// Force i18n to generate translation strings
+	_ = tr("Usage:")
+	_ = tr("Aliases:")
+	_ = tr("Examples:")
+	_ = tr("Available Commands:")
+	_ = tr("Flags:")
+	_ = tr("Global Flags:")
+	_ = tr("Additional help topics:")
+	_ = tr("Use %s for more information about a command.")
+
+	return `{{tr "Usage:"}}{{if .Runnable}}
   {{.UseLine}}{{end}}{{if .HasAvailableSubCommands}}
   {{.CommandPath}} [command]{{end}}{{if gt (len .Aliases) 0}}
 
@@ -56,3 +56,4 @@ const usageTemplate = `{{tr "Usage:"}}{{if .Runnable}}
 
 {{tr "Use %s for more information about a command." (printf "%s %s" .CommandPath "[command] --help" | printf "%q")}}{{end}}
 `
+}

Diff for: commands/board/list.go

@@ -35,9 +35,15 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+type BoardNotFoundError struct{}
+
+func (e *BoardNotFoundError) Error() string {
+	return tr("board not found")
+}
+
 var (
 	// ErrNotFound is returned when the API returns 404
-	ErrNotFound = errors.New(tr("board not found"))
+	ErrNotFound = &BoardNotFoundError{}
 	vidPidURL   = "https://builder.arduino.cc/v3/boards/byVidPid"
 	validVidPid = regexp.MustCompile(`0[xX][a-fA-F\d]{4}`)
 )