From d089d3e863e95caf83343adbbca476f5359412af Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6ran=20Karl?=
 <3951388+JoeKar@users.noreply.github.com>
Date: Mon, 29 Jun 2026 18:18:26 +0200
Subject: [PATCH] buffer: Ignore already invalidated buffers in `Shared()`

`CloseOpenBuffers()` iterates over every open buffer and invalidates them,
while they are kept in the list.
A further de-reference of such a buffer leads to a nil access.
---
 internal/buffer/buffer.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/internal/buffer/buffer.go b/internal/buffer/buffer.go
index d1f8db4b2b..fcf2ddfb30 100644
--- a/internal/buffer/buffer.go
+++ b/internal/buffer/buffer.go
@@ -689,6 +689,9 @@ func (b *Buffer) WordAt(loc Loc) []byte {
 // Shared returns if there are other buffers with the same file as this buffer
 func (b *Buffer) Shared() bool {
 	for _, buf := range OpenBuffers {
+		if buf == nil {
+			continue
+		}
 		if buf != b && buf.SharedBuffer == b.SharedBuffer {
 			return true
 		}