From 11f1949c9d71eeaad28402cb350722a103cc0514 Mon Sep 17 00:00:00 2001
From: shkomg <serhiy.khvashchuk@gmail.com>
Date: Tue, 3 Nov 2026 19:09:56 +0100
Subject: [PATCH] fix(markdown): remove blockquote from code fence lines when
 toggling off

matchLeadingBlockCharacters only recognised a block marker when the
next character was a letter, digit or one of `_*[!`, so "> ```" and
"> ~~~" were never seen as quoted. Toggling a blockquote off over a
fenced code block unquoted the code lines but left the fences quoted.
Allow backtick and tilde after the marker, which also covers lines starting with inline code or strikethrough.
---
 .changeset/quiet-fences-unquote.md |  5 +++++
 src/commonmark/commands.ts         |  2 +-
 test/commonmark/commands.test.ts   | 17 +++++++++++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/quiet-fences-unquote.md

diff --git a/.changeset/quiet-fences-unquote.md b/.changeset/quiet-fences-unquote.md
new file mode 100644
index 00000000..6c3ecc41
--- /dev/null
+++ b/.changeset/quiet-fences-unquote.md
@@ -0,0 +1,5 @@
+---
+"@stackoverflow/stacks-editor": patch
+---
+
+Remove the blockquote from code fence lines when toggling a blockquote off in markdown mode
diff --git a/src/commonmark/commands.ts b/src/commonmark/commands.ts
index 0302cc0e..37bad391 100644
--- a/src/commonmark/commands.ts
+++ b/src/commonmark/commands.ts
@@ -197,7 +197,7 @@ export function matchLeadingBlockCharacters(text: string) {
     // If text is not an ordered list block, check for other block types
     if (!match) {
         // TODO HACK assumes all non-ordered list block types are non-letter characters followed by a single space
-        match = /^[^a-zA-Z0-9]+\s{1}(?=[a-zA-Z0-9_*[!]|$)+/.exec(text)?.[0];
+        match = /^[^a-zA-Z0-9]+\s{1}(?=[a-zA-Z0-9_*[!`~]|$)+/.exec(text)?.[0];
     }
 
     return match || "";
diff --git a/test/commonmark/commands.test.ts b/test/commonmark/commands.test.ts
index 1362ca90..80de7737 100644
--- a/test/commonmark/commands.test.ts
+++ b/test/commonmark/commands.test.ts
@@ -489,6 +489,18 @@ some text`;
                     "\nth"
                 );
             });
+
+            it("multi line, selection spanning a fenced code block", () => {
+                const content = "> ```\n> Some code\n> ```";
+                const state = createState(content, 0, content.length);
+                const command = commands.setBlockTypeCommand(">");
+
+                expect(state).transactionSuccess(
+                    command,
+                    "```\nSome code\n```",
+                    "```\nSome code\n```"
+                );
+            });
         });
 
         /* SWAP */
@@ -605,6 +617,11 @@ some text`;
 
             expect(command).toBe("## ");
         });
+
+        it("return blockquote leading characters before a code fence", () => {
+            expect(commands.matchLeadingBlockCharacters("> ```")).toBe("> ");
+            expect(commands.matchLeadingBlockCharacters("> ~~~")).toBe("> ");
+        });
     });
 
     describe("insertTagLinkCommand", () => {