From 5dc3abedcb2af85372653342c4995307453dd508 Mon Sep 17 00:00:00 2001
From: "Davide P. Cervone" <dpvc@union.edu>
Date: Sun, 14 Jun 2026 19:28:44 -0400
Subject: [PATCH] Ignore braces in array preamble.  (mathjax/MathJax#3565)

---
 testsuite/tests/input/tex/Base.test.ts               |  4 ++++
 .../tests/input/tex/__snapshots__/Base.test.ts.snap  | 12 ++++++++++++
 ts/input/tex/ColumnParser.ts                         |  2 ++
 3 files changed, 18 insertions(+)

diff --git a/testsuite/tests/input/tex/Base.test.ts b/testsuite/tests/input/tex/Base.test.ts
index 6e06df5d7..0052be20f 100644
--- a/testsuite/tests/input/tex/Base.test.ts
+++ b/testsuite/tests/input/tex/Base.test.ts
@@ -4002,6 +4002,10 @@ describe('Complete Array', () => {
     expect(tex2mml('\\begin{array}{> {x} c} X \\end{array}')).toMatchSnapshot();
   });
 
+  it('column { }', () => {
+    expect(tex2mml('\\begin{array}{{c}} X \\end{array}')).toMatchSnapshot();
+  });
+
   it('BadPreamToken', () => {
     expectTexError('\\begin{array}a').toBe('Illegal pream-token (a)');
   });
diff --git a/testsuite/tests/input/tex/__snapshots__/Base.test.ts.snap b/testsuite/tests/input/tex/__snapshots__/Base.test.ts.snap
index bc59e9aa3..db75f586c 100644
--- a/testsuite/tests/input/tex/__snapshots__/Base.test.ts.snap
+++ b/testsuite/tests/input/tex/__snapshots__/Base.test.ts.snap
@@ -1872,6 +1872,18 @@ exports[`Complete Array column @ p m 1`] = `
 </math>"
 `;
 
+exports[`Complete Array column { } 1`] = `
+"<math xmlns="http://www.w3.org/1998/Math/MathML" data-latex="\\begin{array}{{c}} X \\end{array}" display="block">
+  <mtable columnspacing="1em" rowspacing="4pt" data-frame-styles="" framespacing=".5em .125em" data-latex="\\begin{array}{{c}} X \\end{array}">
+    <mtr data-latex="{{c}}">
+      <mtd>
+        <mi data-latex="X">X</mi>
+      </mtd>
+    </mtr>
+  </mtable>
+</math>"
+`;
+
 exports[`Complete Array column b  1`] = `
 "<math xmlns="http://www.w3.org/1998/Math/MathML" data-latex="\\begin{array}{b{1cm}b{1cm}b{1cm}}a &amp; b &amp;c\\\\ d &amp; e &amp; f\\end{array}" display="block">
   <mtable columnspacing="1em" rowspacing="4pt" columnalign="left left left" columnwidth="1cm 1cm 1cm" data-frame-styles="" framespacing=".5em .125em" data-latex="\\text{f}\\end{array}">
diff --git a/ts/input/tex/ColumnParser.ts b/ts/input/tex/ColumnParser.ts
index a0beec563..e4c8a7133 100644
--- a/ts/input/tex/ColumnParser.ts
+++ b/ts/input/tex/ColumnParser.ts
@@ -94,6 +94,8 @@ export class ColumnParser {
     // Ignored
     //
     ' ': (_state) => {},
+    '{': (_state) => {},
+    '}': (_state) => {},
   };
 
   /**