Exclude sketch names ending with a dot

Author: MatteoPologruto

Diff for: commands/sketch/new.go

@@ -19,6 +19,7 @@ import (
 	"context"
 	"errors"
 	"regexp"
+	"strings"
 
 	"github.com/arduino/arduino-cli/arduino"
 	"github.com/arduino/arduino-cli/arduino/globals"
@@ -79,8 +80,8 @@ func validateSketchName(name string) error {
 			len(name),
 			sketchNameMaxLength))}
 	}
-	if !sketchNameValidationRegex.MatchString(name) {
-		return &arduino.CantCreateSketchError{Cause: errors.New(tr(`invalid sketch name "%[1]s": the first character must be alphanumeric or "_", the following ones can also contain "-" and ".".`,
+	if !sketchNameValidationRegex.MatchString(name) || strings.HasSuffix(name, ".") {
+		return &arduino.CantCreateSketchError{Cause: errors.New(tr(`invalid sketch name "%[1]s": the first character must be alphanumeric or "_", the following ones can also contain "-" and ".". The last one cannot be ".".`,
 			name))}
 	}
 	return nil

Diff for: commands/sketch/new_test.go

@@ -30,6 +30,7 @@ func Test_SketchNameWrongPattern(t *testing.T) {
 		".hello",
 		"-hello",
 		"hello*",
+		"hello.",
 		"||||||||||||||",
 		",`hack[}attempt{];",
 	}
@@ -39,7 +40,7 @@ func Test_SketchNameWrongPattern(t *testing.T) {
 			SketchDir:  t.TempDir(),
 		})
 
-		require.EqualError(t, err, fmt.Sprintf(`Can't create sketch: invalid sketch name "%s": the first character must be alphanumeric or "_", the following ones can also contain "-" and ".".`,
+		require.EqualError(t, err, fmt.Sprintf(`Can't create sketch: invalid sketch name "%s": the first character must be alphanumeric or "_", the following ones can also contain "-" and ".". The last one cannot be ".".`,
 			name))
 	}
 }
@@ -78,7 +79,6 @@ func Test_SketchNameOk(t *testing.T) {
 		"h",
 		"h.ello",
 		"h..ello-world",
-		"h..ello-world.",
 		"hello_world__",
 		"_hello_world",
 		string(lengthLimitName),