From 150f30607431752fd6249b0d42cec7ed3331c002 Mon Sep 17 00:00:00 2001
From: Joe Wreschnig <joe.wreschnig@utiq.com>
Date: Fri, 12 Dec 2025 14:01:47 +0100
Subject: [PATCH] Consider nil `*Link`s as per se valid
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Nothing in the JSON:API spec requires links (usually e.g. it’s either
links or data), and nothing requires that if one relation has a related
resource link, all must.

This allows `LinkRelation` to return nil for related resources which may
not have exposed linkage routes in an API.
---
 jsonapi.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/jsonapi.go b/jsonapi.go
index 0f8aa2f..04b4a44 100644
--- a/jsonapi.go
+++ b/jsonapi.go
@@ -109,6 +109,10 @@ func checkLinkValue(linkValue any) (bool, *TypeError) {
 }
 
 func (l *Link) check() error {
+	if l == nil {
+		return nil
+	}
+
 	selfIsEmpty, err := checkLinkValue(l.Self)
 	if err != nil {
 		return err