join: fix unsafe content

shlex.go

@@ -261,7 +261,7 @@ func (t *tokenizer) scanStream() (*Token, error) {
 				switch nextRuneType {
 				case eofRuneClass:
 					switch {
-					case t.index == 0: // tonkenizer contains an empty string
+					case t.index == 0: // tokenizer contains an empty string
 						token.removeLastRaw()
 						token.Type = WORD_TOKEN
 						token.Index = t.index
@@ -422,6 +422,8 @@ func Split(s string) (TokenSlice, error) {
 // It quotes and escapes where appropriate.
 // TODO experimental
 func Join(s []string) string {
+	// TODO how to handle unsafe content? similar to `url.PathEscape` and unsafe by default?
+	// TODO how to handle home/named directory expansion?
 	replacer := strings.NewReplacer(
 		"$", "\\$",
 		"`", "\\`",
@@ -431,7 +433,7 @@ func Join(s []string) string {
 	for _, arg := range s {
 		switch {
 		case arg == "",
-			strings.ContainsAny(arg, `"' `+"\n\r\t"):
+			strings.ContainsAny(arg, `"' `+"`$\n\r\t"): // TODO what about pipeline delimiters
 			formatted = append(formatted, replacer.Replace(fmt.Sprintf("%#v", arg)))
 		default:
 			formatted = append(formatted, arg)

shlex_test.go

@@ -116,3 +116,20 @@ func TestSplit(t *testing.T) {
 		}
 	}
 }
+
+func TestJoin(t *testing.T) {
+	for expected, words := range map[string][]string{
+		``:                          {},
+		`echo "\$(ls)"`:             {"echo", "$(ls)"},
+		"echo \"\\`ls\\`\"":         {"echo", "`ls`"},
+		"echo \"'ls'\"":             {"echo", "'ls'"},
+		`echo "\"ls\""`:             {"echo", `"ls"`},
+		`echo "\$(ls /tmp)"`:        {"echo", "$(ls /tmp)"},
+		`ls /tmp | xargs -n 1 echo`: {"ls", "/tmp", "|", "xargs", "-n", "1", "echo"},
+		`echo "one\ntwo"`:           {"echo", "one\ntwo"},
+	} {
+		if actual := Join(words); actual != expected {
+			t.Errorf("joined words don't match\nactual  : %#v\nexpected: %#v", actual, expected)
+		}
+	}
+}