Don't allow setting invalid colorschemes

Fixes #303

cmd/micro/colorscheme.go

@@ -18,6 +18,24 @@ var colorscheme Colorscheme
 
 var preInstalledColors = []string{"default", "simple", "solarized", "solarized-tc", "atom-dark-tc", "monokai", "gruvbox", "zenburn", "bubblegum"}
 
+// ColorschemeExists checks if a given colorscheme exists
+func ColorschemeExists(colorschemeName string) bool {
+	files, _ := ioutil.ReadDir(configDir)
+	for _, f := range files {
+		if f.Name() == colorschemeName+".micro" {
+			return true
+		}
+	}
+
+	for _, name := range preInstalledColors {
+		if name == colorschemeName {
+			return true
+		}
+	}
+
+	return false
+}
+
 // InitColorscheme picks and initializes the colorscheme when micro starts
 func InitColorscheme() {
 	LoadDefaultColorscheme()
@@ -31,6 +49,7 @@ func LoadDefaultColorscheme() {
 // LoadColorscheme loads the given colorscheme from a directory
 func LoadColorscheme(colorschemeName, dir string) {
 	files, _ := ioutil.ReadDir(dir)
+	found := false
 	for _, f := range files {
 		if f.Name() == colorschemeName+".micro" {
 			text, err := ioutil.ReadFile(dir + "/" + f.Name())
@@ -39,6 +58,7 @@ func LoadColorscheme(colorschemeName, dir string) {
 				continue
 			}
 			colorscheme = ParseColorscheme(string(text))
+			found = true
 		}
 	}
 
@@ -50,8 +70,13 @@ func LoadColorscheme(colorschemeName, dir string) {
 				continue
 			}
 			colorscheme = ParseColorscheme(string(data))
+			found = true
 		}
 	}
+
+	if !found {
+		TermMessage(colorschemeName, "is not a valid colorscheme")
+	}
 }
 
 // ParseColorscheme parses the text definition for a colorscheme and returns the corresponding object

cmd/micro/settings.go

@@ -208,6 +208,12 @@ func DefaultLocalSettings() map[string]interface{} {
 // is local only it will set the local version
 // Use setlocal to force an option to be set locally
 func SetOption(option, value string) error {
+	if option == "colorscheme" {
+		if !ColorschemeExists(value) {
+			return errors.New(value + " is not a valid colorscheme")
+		}
+	}
+
 	if _, ok := globalSettings[option]; !ok {
 		if _, ok := CurView().Buf.Settings[option]; !ok {
 			return errors.New("Invalid option")