Merge pull request #116 from AskAlice/master

fix flashing during erase() on windows terminal

spinner.go

@@ -96,6 +96,9 @@ var validColors = map[string]bool{
 	"bgHiWhite":   true,
 }
 
+// returns true if the OS is windows and the WT_SESSION env variable is set.
+var isWindowsTerminalOnWindows = len(os.Getenv("WT_SESSION")) > 0 && runtime.GOOS == "windows"
+
 // returns a valid color's foreground text color attribute
 var colorAttributeMap = map[string]color.Attribute{
 	// default colors for backwards compatibility
@@ -268,7 +271,7 @@ func (s *Spinner) Start() {
 		s.mu.Unlock()
 		return
 	}
-	if s.HideCursor && runtime.GOOS != "windows" {
+	if s.HideCursor && !isWindowsTerminalOnWindows {
 		// hides the cursor
 		fmt.Fprint(s.Writer, "\033[?25l")
 	}
@@ -287,7 +290,9 @@ func (s *Spinner) Start() {
 						s.mu.Unlock()
 						return
 					}
-					s.erase()
+					if !isWindowsTerminalOnWindows {
+						s.erase()
+					}
 
 					if s.PreUpdate != nil {
 						s.PreUpdate(s)
@@ -326,13 +331,17 @@ func (s *Spinner) Stop() {
 	defer s.mu.Unlock()
 	if s.active {
 		s.active = false
-		if s.HideCursor && runtime.GOOS != "windows" {
+		if s.HideCursor && !isWindowsTerminalOnWindows {
 			// makes the cursor visible
 			fmt.Fprint(s.Writer, "\033[?25h")
 		}
 		s.erase()
 		if s.FinalMSG != "" {
-			fmt.Fprint(s.Writer, s.FinalMSG)
+			if isWindowsTerminalOnWindows {
+				fmt.Fprint(s.Writer, "\r", s.FinalMSG)
+			}else{
+				fmt.Fprint(s.Writer, s.FinalMSG)
+			}
 		}
 		s.stopChan <- struct{}{}
 	}
@@ -390,13 +399,13 @@ func (s *Spinner) UpdateCharSet(cs []string) {
 // Caller must already hold s.lock.
 func (s *Spinner) erase() {
 	n := utf8.RuneCountInString(s.lastOutput)
-	if runtime.GOOS == "windows" {
+	if runtime.GOOS == "windows" && !isWindowsTerminalOnWindows {
 		clearString := "\r" + strings.Repeat(" ", n) + "\r"
 		fmt.Fprint(s.Writer, clearString)
 		s.lastOutput = ""
 		return
 	}
-	fmt.Fprintf(s.Writer, "\r\033[K") // erases to end of line
+	fmt.Fprintf(s.Writer, "\033[K") // erases to end of line
 	s.lastOutput = ""
 }