From a581197a274d96d29d7c5a8989410acb53320029 Mon Sep 17 00:00:00 2001
From: Vendicated <vendicated@riseup.net>
Date: Sun, 27 Sep 2026 20:11:00 +0200
Subject: [PATCH] FakeProfileThemes: fix crashes
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This is quite a weird one. The old regex was causing issues for some users and even Stack overflow errors while
trying to parse the Regex??

Explanation from Claude:

The character classes here (\u{e0061}-\u{e0066}, \u{e0041}-\u{e0046}, \u{e0030}-\u{e0039}) are all in the Unicode Tags block (U+E0000–U+E007F), which is outside the Basic Multilingual Plane — every one of these code points is represented internally as a surrogate pair. When you build a /u-flag regex with several ranges of astral (non-BMP) code points inside a character class, and then apply a repetition quantifier to that class ({1,6}, or +? as in the actual error), V8's Irregexp compiler has to expand/canonicalize the class and unroll the quantifier. For BMP regexes this is cheap, but the astral-range handling triggers a much deeper recursive expansion in the compiler itself.

This is a known class of V8/Chromium bugs (regex-compiler stack overflow on Unicode-mode patterns with supplementary-plane character-class ranges + quantifiers) — it's not something wrong with your logic, it's the compiling of the pattern that blows the native stack on affected Chromium versions/builds, not the matching. That's why it only hits "some users": it depends on their exact V8 build/stack size, not the input string.
---
 src/plugins/fakeProfileThemes/index.tsx | 28 +++++++++++--------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/src/plugins/fakeProfileThemes/index.tsx b/src/plugins/fakeProfileThemes/index.tsx
index b1a284deb..1d462491c 100644
--- a/src/plugins/fakeProfileThemes/index.tsx
+++ b/src/plugins/fakeProfileThemes/index.tsx
@@ -51,26 +51,22 @@ function encode(primary: number, accent: number): string {
     return (padding || "") + " " + encoded;
 }
 
-// Courtesy of Cynthia.
+const DecodeRegex = /\[#([a-fA-F0-9]{1,6}),#([a-fA-F0-9]{1,6})\]/;
 function decode(bio: string): Array<number> | null {
     if (bio == null) return null;
 
-    const colorString = bio.match(
-        /\u{e005b}\u{e0023}([\u{e0061}-\u{e0066}\u{e0041}-\u{e0046}\u{e0030}-\u{e0039}]{1,6})\u{e002c}\u{e0023}([\u{e0061}-\u{e0066}\u{e0041}-\u{e0046}\u{e0030}-\u{e0039}]{1,6})\u{e005d}/u,
-    );
-    if (colorString != null) {
-        const parsed = [...colorString[0]]
-            .map(x => String.fromCodePoint(x.codePointAt(0)! - 0xe0000))
-            .join("");
-        const colors = parsed
-            .substring(1, parsed.length - 1)
-            .split(",")
-            .map(x => parseInt(x.replace("#", "0x"), 16));
-
-        return colors;
-    } else {
-        return null;
+    let ascii = "";
+    for (const ch of bio) {
+        const cp = ch.codePointAt(0)!;
+        if (cp >= 0xe0000 && cp <= 0xe007f) {
+            ascii += String.fromCodePoint(cp - 0xe0000);
+        }
     }
+
+    const match = ascii.match(DecodeRegex);
+    if (!match) return null;
+
+    return [parseInt(match[1], 16), parseInt(match[2], 16)];
 }
 
 const settings = definePluginSettings({