From 39465f9663b8a15b71f45426fba139e1e804c44c Mon Sep 17 00:00:00 2001
From: Sughosha K Joshi <sughoshak6@gmail.com>
Date: Fri, 16 Oct 2026 21:00:05 +0530
Subject: [PATCH 1/2] fix(md): require 4 spaces or tab for indented code blocks
 (#1388)

Update tabRe to require at least four spaces or a tab (/^( {4,}|\t)/)
per CommonMark specification for indented code blocks. Previously,
/^(  +|\t)/ matched lines indented with only 2-3 spaces (such as list
continuation paragraphs), emitting them as raw JavaScript and triggering
syntax errors during execution.

Fixes #1388
---
 src/md.ts       |  2 +-
 test/md.test.ts | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/md.ts b/src/md.ts
index 2b6932e8ad..60f703768c 100644
--- a/src/md.ts
+++ b/src/md.ts
@@ -17,7 +17,7 @@ import { bufToString } from './util.ts'
 
 export function transformMarkdown(buf: Buffer | string): string {
   const out: string[] = []
-  const tabRe = /^(  +|\t)/
+  const tabRe = /^( {4,}|\t)/
   const fenceRe =
     /^(?<indent> {0,3})(?<fence>(`{3,20}|~{3,20}))(?:(?<js>js|javascript|ts|typescript)|(?<bash>sh|shell|bash)|.*)$/
 
diff --git a/test/md.test.ts b/test/md.test.ts
index d37b9c9f6e..76913059c7 100644
--- a/test/md.test.ts
+++ b/test/md.test.ts
@@ -23,7 +23,25 @@ describe('transformMarkdown()', () => {
     })
 
     test('preserves tab-indented blocks after a blank line (legacy behavior)', () => {
-      assert.equal(transformMarkdown('  \n    '), '  \n    ')
+      assert.equal(
+        transformMarkdown('\n\tconsole.log("hello")'),
+        '// \n\tconsole.log("hello")'
+      )
+    })
+
+    test('preserves 4-space indented blocks after a blank line', () => {
+      assert.equal(
+        transformMarkdown('\n    console.log("hello")'),
+        '// \n    console.log("hello")'
+      )
+    })
+
+    test('does not treat indented list/paragraph text with <4 spaces as code blocks (#1388)', () => {
+      const input =
+        '- item 1\n- item 2\n\n  This template assumes you have pnpm installed.'
+      const expected =
+        '// - item 1\n// - item 2\n// \n//   This template assumes you have pnpm installed.'
+      assert.equal(transformMarkdown(input), expected)
     })
 
     test('does not treat a mid-paragraph fence as a fenced block (legacy behavior)', () => {

From 2b08517f2429842d3ca3355a1f5075c8649f55ff Mon Sep 17 00:00:00 2001
From: Sughosha K Joshi <sughoshak6@gmail.com>
Date: Fri, 16 Oct 2026 21:09:53 +0530
Subject: [PATCH 2/2] test(md): account for tabs preceded by 1-3 spaces per
 CommonMark

Update tabRe to /^( {4,}| {0,3}\t)/ to align with CommonMark tab stop
rules where 1-3 spaces before a tab expand to 4-space indentation.
Add corresponding unit test case.
---
 src/md.ts       | 2 +-
 test/md.test.ts | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/md.ts b/src/md.ts
index 60f703768c..47cc032d7c 100644
--- a/src/md.ts
+++ b/src/md.ts
@@ -17,7 +17,7 @@ import { bufToString } from './util.ts'
 
 export function transformMarkdown(buf: Buffer | string): string {
   const out: string[] = []
-  const tabRe = /^( {4,}|\t)/
+  const tabRe = /^( {4,}| {0,3}\t)/
   const fenceRe =
     /^(?<indent> {0,3})(?<fence>(`{3,20}|~{3,20}))(?:(?<js>js|javascript|ts|typescript)|(?<bash>sh|shell|bash)|.*)$/
 
diff --git a/test/md.test.ts b/test/md.test.ts
index 76913059c7..a081662f60 100644
--- a/test/md.test.ts
+++ b/test/md.test.ts
@@ -36,6 +36,13 @@ describe('transformMarkdown()', () => {
       )
     })
 
+    test('preserves blocks indented with spaces and a tab (equivalent to 4 spaces)', () => {
+      assert.equal(
+        transformMarkdown('\n  \tconsole.log("hello")'),
+        '// \n  \tconsole.log("hello")'
+      )
+    })
+
     test('does not treat indented list/paragraph text with <4 spaces as code blocks (#1388)', () => {
       const input =
         '- item 1\n- item 2\n\n  This template assumes you have pnpm installed.'