Update slice flags

- Add check for blank default value
- Reduce indentation of code

flag_int64_slice.go

@@ -137,28 +137,33 @@ func (c *Context) GlobalInt64Slice(name string) []int64 {
 func lookupInt64Slice(name string, set *flag.FlagSet) []int64 {
 	f := set.Lookup(name)
 	if f != nil {
-		if value, ok := f.Value.(*Int64Slice); ok {
-			// extract the slice from asserted value
-			parsed := value.Value()
+		value, ok := f.Value.(*Int64Slice)
+		if !ok {
+			return nil
+		}
+
+		// extract the slice from asserted value
+		parsed := value.Value()
 
-			// extract default value from the flag
-			var defaultVal []int64
-			for _, v := range strings.Split(f.DefValue, ",") {
+		// extract default value from the flag
+		var defaultVal []int64
+		for _, v := range strings.Split(f.DefValue, ",") {
+			if v != "" {
 				int64Value, err := strconv.ParseInt(v, 10, 64)
 				if err != nil {
 					panic(err)
 				}
 				defaultVal = append(defaultVal, int64Value)
 			}
-			// if the current value is not equal to the default value
-			// remove the default values from the flag
-			if !isInt64SliceEqual(parsed, defaultVal) {
-				for _, v := range defaultVal {
-					parsed = removeFromInt64Slice(parsed, v)
-				}
+		}
+		// if the current value is not equal to the default value
+		// remove the default values from the flag
+		if !isInt64SliceEqual(parsed, defaultVal) {
+			for _, v := range defaultVal {
+				parsed = removeFromInt64Slice(parsed, v)
 			}
-			return parsed
 		}
+		return parsed
 	}
 	return nil
 }

flag_int_slice.go

@@ -137,28 +137,32 @@ func (c *Context) GlobalIntSlice(name string) []int {
 func lookupIntSlice(name string, set *flag.FlagSet) []int {
 	f := set.Lookup(name)
 	if f != nil {
-		if value, ok := f.Value.(*IntSlice); ok {
-			// extract the slice from asserted value
-			slice := value.Value()
+		value, ok := f.Value.(*IntSlice)
+		if !ok {
+			return nil
+		}
+		// extract the slice from asserted value
+		slice := value.Value()
 
-			// extract default value from the flag
-			var defaultVal []int
-			for _, v := range strings.Split(f.DefValue, ",") {
+		// extract default value from the flag
+		var defaultVal []int
+		for _, v := range strings.Split(f.DefValue, ",") {
+			if v != "" {
 				intValue, err := strconv.Atoi(v)
 				if err != nil {
 					panic(err)
 				}
 				defaultVal = append(defaultVal, intValue)
 			}
-			// if the current value is not equal to the default value
-			// remove the default values from the flag
-			if !isIntSliceEqual(slice, defaultVal) {
-				for _, v := range defaultVal {
-					slice = removeFromIntSlice(slice, v)
-				}
+		}
+		// if the current value is not equal to the default value
+		// remove the default values from the flag
+		if !isIntSliceEqual(slice, defaultVal) {
+			for _, v := range defaultVal {
+				slice = removeFromIntSlice(slice, v)
 			}
-			return slice
 		}
+		return slice
 	}
 	return nil
 }

flag_string_slice.go

@@ -128,25 +128,27 @@ func (c *Context) GlobalStringSlice(name string) []string {
 func lookupStringSlice(name string, set *flag.FlagSet) []string {
 	f := set.Lookup(name)
 	if f != nil {
-		if value, ok := f.Value.(*StringSlice); ok {
-			// extract the slice from asserted value
-			slice := value.Value()
-
-			// extract default value from the flag
-			var defaultVal []string
-			for _, v := range strings.Split(f.DefValue, ",") {
-				defaultVal = append(defaultVal, v)
-			}
+		value, ok := f.Value.(*StringSlice)
+		if !ok {
+			return nil
+		}
+		// extract the slice from asserted value
+		slice := value.Value()
+
+		// extract default value from the flag
+		var defaultVal []string
+		for _, v := range strings.Split(f.DefValue, ",") {
+			defaultVal = append(defaultVal, v)
+		}
 
-			// if the current value is not equal to the default value
-			// remove the default values from the flag
-			if !isStringSliceEqual(slice, defaultVal) {
-				for _, v := range defaultVal {
-					slice = removeFromStringSlice(slice, v)
-				}
+		// if the current value is not equal to the default value
+		// remove the default values from the flag
+		if !isStringSliceEqual(slice, defaultVal) {
+			for _, v := range defaultVal {
+				slice = removeFromStringSlice(slice, v)
 			}
-			return slice
 		}
+		return slice
 	}
 	return nil
 }