From adcad2775b77fbc8d57dea0249a316659a1056eb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felix=20B=C3=B6hm?= <188768+fb55@users.noreply.github.com>
Date: Sun, 26 Dec 2021 12:36:11 +0100
Subject: [PATCH] fix: Don't add siblings multiple times in
 `appendNextSiblings`

This bug was hidden due to `removeSubsets` ordering elements.

Fixes #655
---
 src/index.ts | 3 ++-
 test/api.ts  | 8 ++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/index.ts b/src/index.ts
index afd936a5..a4f7ccf5 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -115,8 +115,9 @@ function appendNextSiblings<Node, ElementNode extends Node>(
 ): Node[] {
     // Order matters because jQuery seems to check the children before the siblings
     const elems = Array.isArray(elem) ? elem.slice(0) : [elem];
+    const elemsLength = elems.length;
 
-    for (let i = 0; i < elems.length; i++) {
+    for (let i = 0; i < elemsLength; i++) {
         const nextSiblings = getNextSiblings(elems[i], adapter);
         elems.push(...nextSiblings);
     }
diff --git a/test/api.ts b/test/api.ts
index 1f2080a5..23f7603e 100644
--- a/test/api.ts
+++ b/test/api.ts
@@ -255,6 +255,14 @@ describe("API", () => {
             ).toStrictEqual(p);
         });
 
+        it("should not crash when siblings repeat", () => {
+            const dom = parseDOM(`<div></div>`.repeat(51)) as Element[];
+
+            expect(
+                CSSselect.selectAll("+div", dom, { context: dom })
+            ).toHaveLength(50);
+        });
+
         it("should cache results by default", () => {
             const [dom] = parseDOM(
                 '<div id="foo"><p>bar</p></div>'