[nongnu] externals/sly d8c926f 42/47: sbcl: account for SB-DI::DEBUG-FUN-DEBUG-VARS returning NIL

[ELPA Syncer]

branch: externals/sly
commit d8c926f00916c35c7aa838504f9dc0a4696e3447
Author: Jan Moringen <jmoringe@techfak.uni-bielefeld.de>
Commit: João Távora <joaotavora@gmail.com>

    sbcl: account for SB-DI::DEBUG-FUN-DEBUG-VARS returning NIL
    
    * slynk/backend/sbcl.lisp: rework.
    
    Cherry-picked-from: SLIME commit 95bfe00972be936012561cc7e98a1b269fef755f
    Co-authored-by: João Távora <joaotavora@gmail.com>
---
 slynk/backend/sbcl.lisp | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/slynk/backend/sbcl.lisp b/slynk/backend/sbcl.lisp
index 8b30376..d1a782b 100644
--- a/slynk/backend/sbcl.lisp
+++ b/slynk/backend/sbcl.lisp
@@ -1054,7 +1054,7 @@ Return NIL if the symbol is unbound."
                (t :function))
          (doc 'function)))
       (maybe-push
-       :setf (and (setf-expander symbol) 
+       :setf (and (setf-expander symbol)
                   (doc 'setf)))
       (maybe-push
        :type (if (sb-int:info :type :kind symbol)
@@ -1410,16 +1410,17 @@ stack."
                               all-vars)))
          more-context
          more-count)
-    (values (loop for v across vars
-                  unless 
-                  (case (debug-var-info v)
-                    (:more-context
-                     (setf more-context (debug-var-value v frame loc))
-                     t)
-                    (:more-count
-                     (setf more-count (debug-var-value v frame loc))
-                     t))
-                  collect v)
+    (values (when vars
+              (loop for v across vars
+                    unless
+                    (case (debug-var-info v)
+                      (:more-context
+                       (setf more-context (debug-var-value v frame loc))
+                       t)
+                      (:more-count
+                       (setf more-count (debug-var-value v frame loc))
+                       t))
+                    collect v))
             more-context more-count)))
 
 (defun debug-var-value (var frame location)
@@ -1760,7 +1761,7 @@ stack."
         (setf (mailbox.queue mbox)
               (nconc (mailbox.queue mbox) (list message)))
         (sb-thread:condition-broadcast (mailbox.waitqueue mbox)))))
-  
+
   (defimplementation receive-if (test &optional timeout)
     (let* ((mbox (mailbox (current-thread)))
            (mutex (mailbox.mutex mbox))