From e9f0eed707ece9e29c3bf340900d1acb42acaddd Mon Sep 17 00:00:00 2001
From: Tony Brix <tony@brix.ninja>
Date: Thu, 18 Apr 2024 23:06:58 -0600
Subject: [PATCH] fix: fix Setext continuation in blockquote (#3257)

---
 src/Tokenizer.ts                           |  4 +++-
 src/rules.ts                               |  4 ++--
 test/specs/commonmark/commonmark.0.31.json |  3 +--
 test/specs/gfm/commonmark.0.31.json        |  3 +--
 test/specs/new/blockquote_setext.html      | 19 +++++++++++++++++++
 test/specs/new/blockquote_setext.md        | 16 ++++++++++++++++
 test/specs/new/setext_no_blankline.html    |  2 --
 test/specs/new/setext_no_blankline.md      |  3 ---
 8 files changed, 42 insertions(+), 12 deletions(-)
 create mode 100644 test/specs/new/blockquote_setext.html
 create mode 100644 test/specs/new/blockquote_setext.md

diff --git a/src/Tokenizer.ts b/src/Tokenizer.ts
index 9daee0b6..10b31454 100644
--- a/src/Tokenizer.ts
+++ b/src/Tokenizer.ts
@@ -156,7 +156,9 @@ export class _Tokenizer {
   blockquote(src: string): Tokens.Blockquote | undefined {
     const cap = this.rules.block.blockquote.exec(src);
     if (cap) {
-      const text = rtrim(cap[0].replace(/^ *>[ \t]?/gm, ''), '\n');
+      // precede setext continuation with 4 spaces so it isn't a setext
+      let text = cap[0].replace(/\n {0,3}((?:=+|-+) *)(?=\n|$)/g, '\n    $1');
+      text = rtrim(text.replace(/^ *>[ \t]?/gm, ''), '\n');
       const top = this.lexer.state.top;
       this.lexer.state.top = true;
       const tokens = this.lexer.blockTokens(text);
diff --git a/src/rules.ts b/src/rules.ts
index cd6baf90..07f0990e 100644
--- a/src/rules.ts
+++ b/src/rules.ts
@@ -58,7 +58,7 @@ const html = edit(
 const paragraph = edit(_paragraph)
   .replace('hr', hr)
   .replace('heading', ' {0,3}#{1,6}(?:\\s|$)')
-  .replace('|lheading', '') // setex headings don't interrupt commonmark paragraphs
+  .replace('|lheading', '') // setext headings don't interrupt commonmark paragraphs
   .replace('|table', '')
   .replace('blockquote', ' {0,3}>')
   .replace('fences', ' {0,3}(?:`{3,}(?=[^`\\n]*\\n)|~{3,})[^\\n]*\\n')
@@ -117,7 +117,7 @@ const blockGfm: Record<BlockKeys, RegExp> = {
   paragraph: edit(_paragraph)
     .replace('hr', hr)
     .replace('heading', ' {0,3}#{1,6}(?:\\s|$)')
-    .replace('|lheading', '') // setex headings don't interrupt commonmark paragraphs
+    .replace('|lheading', '') // setext headings don't interrupt commonmark paragraphs
     .replace('table', gfmTable) // interrupt paragraphs with table
     .replace('blockquote', ' {0,3}>')
     .replace('fences', ' {0,3}(?:`{3,}(?=[^`\\n]*\\n)|~{3,})[^\\n]*\\n')
diff --git a/test/specs/commonmark/commonmark.0.31.json b/test/specs/commonmark/commonmark.0.31.json
index 1fdabe7b..f9b5db2e 100644
--- a/test/specs/commonmark/commonmark.0.31.json
+++ b/test/specs/commonmark/commonmark.0.31.json
@@ -743,8 +743,7 @@
     "example": 93,
     "start_line": 1527,
     "end_line": 1537,
-    "section": "Setext headings",
-    "shouldFail": true
+    "section": "Setext headings"
   },
   {
     "markdown": "- Foo\n---\n",
diff --git a/test/specs/gfm/commonmark.0.31.json b/test/specs/gfm/commonmark.0.31.json
index 7e7421ff..ff36b9f4 100644
--- a/test/specs/gfm/commonmark.0.31.json
+++ b/test/specs/gfm/commonmark.0.31.json
@@ -743,8 +743,7 @@
     "example": 93,
     "start_line": 1527,
     "end_line": 1537,
-    "section": "Setext headings",
-    "shouldFail": true
+    "section": "Setext headings"
   },
   {
     "markdown": "- Foo\n---\n",
diff --git a/test/specs/new/blockquote_setext.html b/test/specs/new/blockquote_setext.html
new file mode 100644
index 00000000..313d6acc
--- /dev/null
+++ b/test/specs/new/blockquote_setext.html
@@ -0,0 +1,19 @@
+<blockquote>
+  <p>not heading 1 ==</p>
+</blockquote>
+
+<blockquote>
+  <p>not heading 2 --</p>
+</blockquote>
+
+<blockquote>
+  <h1>heading 1</h1>
+</blockquote>
+
+<blockquote>
+  <h2>heading 2</h2>
+</blockquote>
+
+<blockquote>
+  <p>not heading 1 == not heading 2 with br<br />--</p>
+</blockquote>
diff --git a/test/specs/new/blockquote_setext.md b/test/specs/new/blockquote_setext.md
new file mode 100644
index 00000000..0b164a91
--- /dev/null
+++ b/test/specs/new/blockquote_setext.md
@@ -0,0 +1,16 @@
+> not heading 1
+==
+
+> not heading 2
+--
+
+> heading 1
+> ==
+
+> heading 2
+> --
+
+> not heading 1
+==
+> not heading 2 with br  
+--
diff --git a/test/specs/new/setext_no_blankline.html b/test/specs/new/setext_no_blankline.html
index 88657aa7..695eecc7 100644
--- a/test/specs/new/setext_no_blankline.html
+++ b/test/specs/new/setext_no_blankline.html
@@ -4,8 +4,6 @@
 <p>fenced code block</p>
 <pre><code>=
 </code></pre>
-<blockquote><h1>blockquote</h1>
-</blockquote>
 <h3>heading</h3>
 <p>=</p>
 <html>
diff --git a/test/specs/new/setext_no_blankline.md b/test/specs/new/setext_no_blankline.md
index f98ebd63..33bd2540 100644
--- a/test/specs/new/setext_no_blankline.md
+++ b/test/specs/new/setext_no_blankline.md
@@ -6,9 +6,6 @@ fenced code block
 =
 ```
 
-> blockquote
-=
-
 ### heading
 =