improve escaping

yaml/pretty/util.go

@@ -65,7 +65,7 @@ func isZero(v interface{}) bool {
 
 func isQuoted(b rune) bool {
 	switch b {
-	case '#', ',', '[', ']', '{', '}', '&', '*', '!', '|', '>', '\'', '"', '%', '@', '`':
+	case '#', ',', '[', ']', '{', '}', '&', '*', '!', '\'', '"', '%', '@', '`':
 		return true
 	case '\a', '\b', '\f', '\n', '\r', '\t', '\v':
 		return true

yaml/pretty/writer.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 	"sort"
 	"strconv"
+	"strings"
 
 	"github.com/drone/drone-yaml/yaml"
 )
@@ -195,6 +196,15 @@ func writeEncode(w writer, v string) {
 		w.WriteByte('"')
 		return
 	}
+	trimmed := strings.TrimSpace(v)
+	if strings.HasPrefix(trimmed, "| ") {
+		fmt.Fprintf(w, "%q", v)
+		return
+	}
+	if strings.HasPrefix(trimmed, "> ") {
+		fmt.Fprintf(w, "%q", v)
+		return
+	}
 	var prev rune
 	for _, b := range v {
 		if isQuoted(b) {