Merge pull request #256 from kiwicom/ms/issue-255

Escape single quotes in single-quoted string

.codecov.yml

@@ -26,3 +26,6 @@ comment:
   layout: "header,diff"
   behavior: default
   require_changes: no
+
+ignore:
+  - ast

ast/ast.go

@@ -793,11 +793,25 @@ func (n *StringNode) GetValue() interface{} {
 	return n.Value
 }
 
+// escapeSingleQuote escapes s to a single quoted scalar.
+// https://yaml.org/spec/1.2.2/#732-single-quoted-style
+func escapeSingleQuote(s string) string {
+	var sb strings.Builder
+	growLen := len(s) + // s includes also one ' from the doubled pair
+		2 + // opening and closing '
+		strings.Count(s, "'") // ' added by ReplaceAll
+	sb.Grow(growLen)
+	sb.WriteString("'")
+	sb.WriteString(strings.ReplaceAll(s, "'", "''"))
+	sb.WriteString("'")
+	return sb.String()
+}
+
 // String string value to text with quote or literal header if required
 func (n *StringNode) String() string {
 	switch n.Token.Type {
 	case token.SingleQuoteType:
-		quoted := fmt.Sprintf(`'%s'`, n.Value)
+		quoted := escapeSingleQuote(n.Value)
 		if n.Comment != nil {
 			return addCommentString(quoted, n.Comment)
 		}

ast/ast_test.go

@@ -0,0 +1,11 @@
+package ast
+
+import "testing"
+
+func TestEscapeSingleQuote(t *testing.T) {
+	expected := `'Victor''s victory'`
+	got := escapeSingleQuote("Victor's victory")
+	if got != expected {
+		t.Fatalf("expected:%s\ngot:%s", expected, got)
+	}
+}