From e4b2aab2a38f3418c1871f38b2fb7d229d645fc8 Mon Sep 17 00:00:00 2001
From: Neil <neil@stably.ai>
Date: Fri, 18 Sep 2026 23:38:06 -0700
Subject: [PATCH] fix(editor): match fence suffix whitespace rules

---
 .../components/editor/markdown-fence-scanner.ts | 17 ++++++++++-------
 .../editor/markdown-scanner-boundaries.test.ts  |  2 +-
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/renderer/src/components/editor/markdown-fence-scanner.ts b/src/renderer/src/components/editor/markdown-fence-scanner.ts
index 3d1de134eba..f01ffaacc30 100644
--- a/src/renderer/src/components/editor/markdown-fence-scanner.ts
+++ b/src/renderer/src/components/editor/markdown-fence-scanner.ts
@@ -10,17 +10,20 @@ export type MarkdownFenceTracker = {
 // Top-level fence delimiters may be indented by at most three spaces.
 const FENCE_LINE = /[ ]{0,3}(`{3,}|~{3,})/y
 function hasClosingSuffix(content: string, start: number, end: number): boolean {
+  let sawWhitespace = false
   for (let index = start; index < end; index += 1) {
     const character = content.charCodeAt(index)
-    if (
-      character !== 126 &&
-      character !== 96 &&
-      character !== 32 &&
-      character !== 9 &&
-      character !== 13
-    ) {
+    if (character === 32 || character === 9 || character === 13) {
+      sawWhitespace = true
+      continue
+    }
+    if ((character === 126 || character === 96) && !sawWhitespace) {
+      continue
+    }
+    if (character !== 126 && character !== 96) {
       return false
     }
+    return false
   }
   return true
 }
diff --git a/src/renderer/src/components/editor/markdown-scanner-boundaries.test.ts b/src/renderer/src/components/editor/markdown-scanner-boundaries.test.ts
index 4b965e09064..49b13152376 100644
--- a/src/renderer/src/components/editor/markdown-scanner-boundaries.test.ts
+++ b/src/renderer/src/components/editor/markdown-scanner-boundaries.test.ts
@@ -34,7 +34,7 @@ it.each(['\n', '\r\n', '\r'])('retains %j terminators while stripping code', (eo
   )
 })
 
-it.each(['```~~~', '      ```'])('matches the parser on the closer %j', (closer) => {
+it.each(['```~~~', '``` ~', '      ```'])('matches the parser on the closer %j', (closer) => {
   const source = `\`\`\`\ncode\n${closer}\n<div>after</div>\n`
   const code = marked.lexer(source)[0]
   expect(code.type).toBe('code')