From 3a1070d0619bea942f6850474ddfb93f6a19ba77 Mon Sep 17 00:00:00 2001
From: Azat Khuzhin <a3at.mail@gmail.com>
Date: Sun, 22 Dec 2024 21:13:04 +0100
Subject: [PATCH] Forbid incorrect document start (---)

Previously documents like the following was simply ignored:

    ----
    # foo
    bar: bam
---
 src/exp.h                              |  2 +-
 test/integration/handler_spec_test.cpp | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/exp.h b/src/exp.h
index c8837f0f8..a44718eb2 100644
--- a/src/exp.h
+++ b/src/exp.h
@@ -82,7 +82,7 @@ inline const RegEx& Utf8_ByteOrderMark() {
 // actual tags
 
 inline const RegEx& DocStart() {
-  static const RegEx e = RegEx("---") + (BlankOrBreak() | RegEx());
+  static const RegEx e = RegEx("---");
   return e;
 }
 inline const RegEx& DocEnd() {
diff --git a/test/integration/handler_spec_test.cpp b/test/integration/handler_spec_test.cpp
index 8cba9023d..cdc004683 100644
--- a/test/integration/handler_spec_test.cpp
+++ b/test/integration/handler_spec_test.cpp
@@ -1682,5 +1682,15 @@ TEST_F(HandlerSpecTest, Ex8_22_BlockCollectionNodes) {
   EXPECT_CALL(handler, OnDocumentEnd());
   Parse(ex8_22);
 }
+
+TEST_F(HandlerSpecTest, InvalidDocStart1) {
+  EXPECT_THROW_PARSER_EXCEPTION(IgnoreParse("----\nbaz: 1"),
+                                ErrorMsg::BLOCK_ENTRY);
+}
+TEST_F(HandlerSpecTest, InvalidDocStart2) {
+  EXPECT_THROW_PARSER_EXCEPTION(IgnoreParse("----\n# foo\nbaz: 1"),
+                                ErrorMsg::BLOCK_ENTRY);
+}
+
 }  // namespace
 }  // namespace YAML