From fda02e9acbbf69b64076ad24e71a1a3197991673 Mon Sep 17 00:00:00 2001
From: Lilleman auf Larv <lilleman@larvit.se>
Date: Wed, 28 Oct 2026 13:08:01 +0100
Subject: [PATCH] =?UTF-8?q?Answer=20principles=20round=201:=200=20?=
 =?UTF-8?q?=F0=9F=94=B4,=202=20=F0=9F=9F=A1=20(0=20misread);=20the=20end?=
 =?UTF-8?q?=20of=20the=20text=20is=20destinationEnds'=20last=20stop,=20and?=
 =?UTF-8?q?=20a=20nested=20unclosed=20paren=20after=20a=20space=20is=20pin?=
 =?UTF-8?q?ned?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/markdown/commonmark/link-syntax.test.ts |  1 +
 src/markdown/commonmark/link-syntax.ts      | 21 +++++++--------------
 2 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/src/markdown/commonmark/link-syntax.test.ts b/src/markdown/commonmark/link-syntax.test.ts
index 4d0b60c..10fc996 100644
--- a/src/markdown/commonmark/link-syntax.test.ts
+++ b/src/markdown/commonmark/link-syntax.test.ts
@@ -33,6 +33,7 @@ test('a destination holding an unbalanced unescaped `(` at a space or the end re
   assert.deepEqual(targets('[a](b(c "t") [d](e)'), [undefined, { destination: 'e', length: 3 }])
   assert.deepEqual(targets('[a](b(c) "t")'), [{ destination: 'b(c)', length: 10, title: 't' }])
   assert.deepEqual(targets('[a](b((c) "t")'), [undefined])
+  assert.deepEqual(targets('[a](b(c d))'), [undefined])
   assert.equal(readDestination('b(c', 0), undefined)
   assert.equal(readDestination('b(c d', 0), undefined)
   assert.deepEqual(readDestination('b(c) d', 0), { length: 4, value: 'b(c)' })
diff --git a/src/markdown/commonmark/link-syntax.ts b/src/markdown/commonmark/link-syntax.ts
index 25a8e29..bcaba70 100644
--- a/src/markdown/commonmark/link-syntax.ts
+++ b/src/markdown/commonmark/link-syntax.ts
@@ -72,27 +72,20 @@ export function targetMemo(text: string): TargetMemo {
   return { destinationEnds: undefined, tails: new Map(), text }
 }
 
-// Of the starts still open at a stop, only the innermost has its parentheses balanced; the others hold a `(` nothing closed and keep no end.
-function stopAt(ends: Int32Array, open: number[], index: number): void {
-  const innermost = open.pop()
-  if (innermost !== undefined) ends[innermost] = index
-  open.length = 0
-}
-
-// `ends[start]` is where an unbracketed destination from `start` stops, filled in one pass for every start a target can have: just after a `(`, a space or a control character, and 0, where `readDestination`'s run begins.
+// `ends[start]` is where an unbracketed destination from `start` stops, filled in one pass for every start a target can have: just after a `(`, a space or a control character, and 0, where `readDestination`'s run begins. At a stop only the innermost open start has its parentheses balanced, so the starts below it keep no end.
 function destinationEnds(text: string): Int32Array {
   const ends = new Int32Array(text.length + 1)
-  const open = [0]
-  for (let index = 0; index < text.length; index += backslashEscape(text, index) === undefined ? 1 : 2) {
+  let open = [0]
+  for (let index = 0; index <= text.length; index += backslashEscape(text, index) === undefined ? 1 : 2) {
     const character = text.charAt(index)
     if (character === '(') open.push(index + 1)
     const start = character === ')' ? open.pop() : undefined
     if (start !== undefined) ends[start] = index
-    if (character !== ' ' && !holdsControlCharacter(character)) continue
-    stopAt(ends, open, index)
-    open.push(index + 1)
+    if (index < text.length && character !== ' ' && !holdsControlCharacter(character)) continue
+    const innermost = open.pop()
+    if (innermost !== undefined) ends[innermost] = index
+    open = [index + 1]
   }
-  stopAt(ends, open, text.length)
   return ends
 }