Make DefaultPackWindow const public and document it

Signed-off-by: Javi Fontan <jfontan@gmail.com>

Author: jfontan

config/config.go

@@ -70,7 +70,7 @@ func NewConfig() *Config {
 		Raw:        format.New(),
 	}
 
-	config.Pack.Window = defaultPackWindow
+	config.Pack.Window = DefaultPackWindow
 
 	return config
 }
@@ -101,7 +101,9 @@ const (
 	worktreeKey      = "worktree"
 	windowKey        = "window"
 
-	defaultPackWindow = uint(10)
+	// DefaultPackWindow holds the number of previous objects used to
+	// generate deltas. The value 10 is the same used by git command.
+	DefaultPackWindow = uint(10)
 )
 
 // Unmarshal parses a git-config file and stores it.
@@ -135,7 +137,7 @@ func (c *Config) unmarshalPack() error {
 	s := c.Raw.Section(packSection)
 	window := s.Options.Get(windowKey)
 	if window == "" {
-		c.Pack.Window = defaultPackWindow
+		c.Pack.Window = DefaultPackWindow
 	} else {
 		winUint, err := strconv.ParseUint(window, 10, 32)
 		if err != nil {
@@ -196,7 +198,7 @@ func (c *Config) marshalCore() {
 
 func (c *Config) marshalPack() {
 	s := c.Raw.Section(packSection)
-	if c.Pack.Window != defaultPackWindow {
+	if c.Pack.Window != DefaultPackWindow {
 		s.SetOption(windowKey, fmt.Sprintf("%d", c.Pack.Window))
 	}
 }

config/config_test.go

@@ -163,5 +163,5 @@ func (s *ConfigSuite) TestRemoteConfigDefaultValues(c *C) {
 	c.Assert(config.Remotes, HasLen, 0)
 	c.Assert(config.Submodules, HasLen, 0)
 	c.Assert(config.Raw, NotNil)
-	c.Assert(config.Pack.Window, Equals, defaultPackWindow)
+	c.Assert(config.Pack.Window, Equals, DefaultPackWindow)
 }