Marshal YAML 1.1 bool-like to strings (#583)

We adhere to the YAML 1.2 for input, but only parsing "on", "off", and friends, as strings rather than bools. When outputting however we will ensure that we quote these cases. Failure to do so forces makes the output ambiguous if it then to be parsed by a YAML 1.2 parser.
go-yaml · Mar 13, 2020 · 9f266ea · 9f266ea
1 parent a6ecf24
commit 9f266ea
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Showing 2 changed files with 22 additions and 1 deletion.
diff --git a/encode.go b/encode.go
@@ -298,6 +298,21 @@ func isBase60Float(s string) (result bool) {
 // is bogus. In practice parsers do not enforce the "\.[0-9_]*" suffix.
 var base60float = regexp.MustCompile(`^[-+]?[0-9][0-9_]*(?::[0-5]?[0-9])+(?:\.[0-9_]*)?$`)
 
+// isOldBool returns whether s is bool notation as defined in YAML 1.1.
+//
+// We continue to force strings that YAML 1.1 would interpret as booleans to be
+// rendered as quotes strings so that the marshalled output valid for YAML 1.1
+// parsing.
+func isOldBool(s string) (result bool) {
+	switch s {
+	case "y", "Y", "yes", "Yes", "YES", "on", "On", "ON",
+		"n", "N", "no", "No", "NO", "off", "Off", "OFF":
+		return true
+	default:
+		return false
+	}
+}
+
 func (e *encoder) stringv(tag string, in reflect.Value) {
 	var style yaml_scalar_style_t
 	s := in.String()
@@ -319,7 +334,7 @@ func (e *encoder) stringv(tag string, in reflect.Value) {
 		// tag when encoded unquoted. If it doesn't,
 		// there's no need to quote it.
 		rtag, _ := resolve("", s)
-		canUsePlain = rtag == strTag && !isBase60Float(s)
+		canUsePlain = rtag == strTag && !(isBase60Float(s) || isOldBool(s))
 	}
 	// Note: it's possible for user code to emit invalid YAML
 	// if they explicitly specify a tag and a string containing

diff --git a/encode_test.go b/encode_test.go
@@ -176,6 +176,12 @@ var marshalTests = []struct {
 	}, {
 		&struct{ A bool }{true},
 		"a: true\n",
+	}, {
+		&struct{ A string }{"true"},
+		"a: \"true\"\n",
+	}, {
+		&struct{ A string }{"off"},
+		"a: \"off\"\n",
 	},
 
 	// Conditional flag