Handle %stacks not being a pair

Not sure when this would happen, but guard against it.
2025-05-15 09:25:30 +01:00 · 2025-05-15 09:25:30 +01:00 · 7ba77010ae
commit 7ba77010ae
parent 8c63ed7b4e
4 changed files with 53 additions and 38 deletions
--- a/knots.scm
+++ b/knots.scm
@ -67,11 +67,14 @@
 (define* (print-backtrace-and-exception/knots
          exn
          #:key (port (current-error-port)))
-  (let* ((stack (match (fluid-ref %stacks)
-                  ((stack-tag . prompt-tag)
-                   (make-stack #t
-                               0 prompt-tag
-                               0 (and prompt-tag 1)))))
+  (let* ((stack
+          (match (fluid-ref %stacks)
+            ((stack-tag . prompt-tag)
+             (make-stack #t
+                         0 prompt-tag
+                         0 (and prompt-tag 1)))
+            (_
+             (make-stack #t))))
         (error-string
          (call-with-output-string
            (lambda (port)