From e6298723247ac5c3e9d5e94ac37547d1cfaa5efd Mon Sep 17 00:00:00 2001
From: Chris Markiewicz <effigies@gmail.com>
Date: Thu, 12 Oct 2023 19:17:42 -0400
Subject: [PATCH] FIX: exists(null, ...) == 0

---
 bids-validator/src/schema/expressionLanguage.ts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/bids-validator/src/schema/expressionLanguage.ts b/bids-validator/src/schema/expressionLanguage.ts
index 512319965..93ba08445 100644
--- a/bids-validator/src/schema/expressionLanguage.ts
+++ b/bids-validator/src/schema/expressionLanguage.ts
@@ -1,4 +1,8 @@
 function exists(list: string[], rule: string = 'dataset'): number {
+  if (list == null) {
+    return 0
+  }
+
   const prefix: string[] = []
 
   // Stimuli and subject-relative paths get prefixes