From 3153469a2cddd2134fa7fcb4662485d1f7fad00e Mon Sep 17 00:00:00 2001
From: Ray Miller <ray@1729.org.uk>
Date: Wed, 8 Jan 2025 09:56:12 +0000
Subject: [PATCH] Validate play vars

---
 modules/ordo/play.scm | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/modules/ordo/play.scm b/modules/ordo/play.scm
index 8e5e606..aa2036c 100644
--- a/modules/ordo/play.scm
+++ b/modules/ordo/play.scm
@@ -31,6 +31,10 @@
   (unless (every (lambda (h) (and (pair? h) (handler? (cdr h)))) handlers)
     (error (format #f "invalid handlers: ~a" handlers))))
 
+(define (validate-vars vars)
+  (unless (every pair? vars)
+    (error (format #f "invalid vars: ~a" vars))))
+
 (define (validate-triggers tasks handlers)
   (for-each (lambda (task)
               (for-each (lambda (trigger)
@@ -46,6 +50,10 @@
   (validate-tasks tasks)
   (validate-handlers handlers)
   (validate-triggers tasks handlers)
+  (validate-vars vars)
+  ;; Reconstruct the vars here because, when a quoted list is passed in the
+  ;; play, it can result in an error (expected mutable pair) from assoc-set!
+  ;; from register-context-var!.
   (make-play description connection (fold (match-lambda* (((k . v) accum) (alist-cons k v accum))) '() vars) tasks handlers))
 
 (define (run-play play)