From 13626af92af7642eba79837842c59602201d52a1 Mon Sep 17 00:00:00 2001
From: "Dr. Andre Vehreschild" <101638173+vehre-x41@users.noreply.github.com>
Date: Thu, 21 Apr 2022 15:19:51 +0200
Subject: [PATCH] Fix escaping anchors in keys (#1101)

---
 src/emitterutils.cpp              |  4 ++--
 src/exp.h                         |  4 ++++
 test/integration/emitter_test.cpp | 10 ++++++++++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/emitterutils.cpp b/src/emitterutils.cpp
index c6ad5e5..6cdf6de 100644
--- a/src/emitterutils.cpp
+++ b/src/emitterutils.cpp
@@ -176,11 +176,11 @@ bool IsValidPlainScalar(const std::string& str, FlowType::value flowType,
   static const RegEx& disallowed_flow =
       Exp::EndScalarInFlow() | (Exp::BlankOrBreak() + Exp::Comment()) |
       Exp::NotPrintable() | Exp::Utf8_ByteOrderMark() | Exp::Break() |
-      Exp::Tab();
+      Exp::Tab() | Exp::Ampersand();
   static const RegEx& disallowed_block =
       Exp::EndScalar() | (Exp::BlankOrBreak() + Exp::Comment()) |
       Exp::NotPrintable() | Exp::Utf8_ByteOrderMark() | Exp::Break() |
-      Exp::Tab();
+      Exp::Tab() | Exp::Ampersand();
   const RegEx& disallowed =
       flowType == FlowType::Flow ? disallowed_flow : disallowed_block;
 
diff --git a/src/exp.h b/src/exp.h
index a0d6d76..c8837f0 100644
--- a/src/exp.h
+++ b/src/exp.h
@@ -117,6 +117,10 @@ inline const RegEx& ValueInJSONFlow() {
   static const RegEx e = RegEx(':');
   return e;
 }
+inline const RegEx& Ampersand() {
+  static const RegEx e = RegEx('&');
+  return e;
+}
 inline const RegEx Comment() {
   static const RegEx e = RegEx('#');
   return e;
diff --git a/test/integration/emitter_test.cpp b/test/integration/emitter_test.cpp
index 560f631..53407c9 100644
--- a/test/integration/emitter_test.cpp
+++ b/test/integration/emitter_test.cpp
@@ -1624,6 +1624,15 @@ NodeB:
   k: [*k0, *k1])");
 }
 
+TEST_F(EmitterTest, AnchorEncoding) {
+  Node node;
+  node["--- &$ [*$]1"] = 1;
+  out << node;
+  ExpectEmit("\"--- &$ [*$]1\": 1");
+  Node reparsed = YAML::Load(out.c_str());
+  EXPECT_EQ(reparsed["--- &$ [*$]1"].as<int>(), 1);
+}
+
 class EmitterErrorTest : public ::testing::Test {
  protected:
   void ExpectEmitError(const std::string& expectedError) {
@@ -1694,5 +1703,6 @@ TEST_F(EmitterErrorTest, InvalidAlias) {
 
   ExpectEmitError(ErrorMsg::INVALID_ALIAS);
 }
+
 }  // namespace
 }  // namespace YAML