From 41fb46492831fc3fbeaefe5a4ff613d1b9757b3a Mon Sep 17 00:00:00 2001
From: tdakkota <tanc13@yandex.ru>
Date: Mon, 10 Apr 2023 08:44:51 +0300
Subject: [PATCH] fix: escape shorthand tags if needed

---
 emitterc.go    | 12 +++++++-----
 encode_test.go | 15 +++++++++++++++
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/emitterc.go b/emitterc.go
index f061b3d..354f5c6 100644
--- a/emitterc.go
+++ b/emitterc.go
@@ -420,7 +420,7 @@ func yaml_emitter_emit_document_start(emitter *yaml_emitter_t, event *yaml_event
 				if !yaml_emitter_write_tag_handle(emitter, tag_directive.handle) {
 					return false
 				}
-				if !yaml_emitter_write_tag_content(emitter, tag_directive.prefix, true) {
+				if !yaml_emitter_write_tag_content(emitter, tag_directive.prefix, true, true) {
 					return false
 				}
 				if !yaml_emitter_write_indent(emitter) {
@@ -1080,7 +1080,7 @@ func yaml_emitter_process_tag(emitter *yaml_emitter_t) bool {
 			return false
 		}
 		if len(emitter.tag_data.suffix) > 0 {
-			if !yaml_emitter_write_tag_content(emitter, emitter.tag_data.suffix, false) {
+			if !yaml_emitter_write_tag_content(emitter, emitter.tag_data.suffix, need_brackets, false) {
 				return false
 			}
 		}
@@ -1094,7 +1094,7 @@ func yaml_emitter_process_tag(emitter *yaml_emitter_t) bool {
 		if !yaml_emitter_write_indicator(emitter, []byte("!<"), true, false, false) {
 			return false
 		}
-		if !yaml_emitter_write_tag_content(emitter, emitter.tag_data.suffix, false) {
+		if !yaml_emitter_write_tag_content(emitter, emitter.tag_data.suffix, false, false) {
 			return false
 		}
 		if !yaml_emitter_write_indicator(emitter, []byte{'>'}, false, false, false) {
@@ -1562,7 +1562,7 @@ func yaml_emitter_write_tag_handle(emitter *yaml_emitter_t, value []byte) bool {
 	return true
 }
 
-func yaml_emitter_write_tag_content(emitter *yaml_emitter_t, value []byte, need_whitespace bool) bool {
+func yaml_emitter_write_tag_content(emitter *yaml_emitter_t, value []byte, allow_uri, need_whitespace bool) bool {
 	if need_whitespace && !emitter.whitespace {
 		if !put(emitter, ' ') {
 			return false
@@ -1571,8 +1571,10 @@ func yaml_emitter_write_tag_content(emitter *yaml_emitter_t, value []byte, need_
 	for i := 0; i < len(value); {
 		var must_write bool
 		switch value[i] {
-		case ';', '/', '?', ':', '@', '&', '=', '+', '$', ',', '_', '.', '~', '*', '\'', '(', ')', '[', ']':
+		case ';', '/', '?', ':', '@', '&', '=', '+', '$', '_', '.', '~', '*', '\'', '(', ')':
 			must_write = true
+		case '{', '}', '[', ']', ',':
+			must_write = allow_uri
 		default:
 			must_write = is_alpha(value, i)
 		}
diff --git a/encode_test.go b/encode_test.go
index f355f5f..1dce883 100644
--- a/encode_test.go
+++ b/encode_test.go
@@ -717,6 +717,21 @@ var marshalTests = []struct {
 		},
 		"!<!!>\n",
 	},
+	// https://github.com/go-faster/yaml/issues/50
+	{
+		yaml.Node{
+			Kind: yaml.ScalarNode,
+			Tag:  "[",
+		},
+		"!<%5B>\n",
+	},
+	{
+		yaml.Node{
+			Kind: yaml.ScalarNode,
+			Tag:  "]",
+		},
+		"!<%5D>\n",
+	},
 
 	// Enforced tagging with shorthand notation (issue #616).
 	{