transient-infix-read: Avoid turning nil into "" if multi-value is non-nil

If STRINGS is nil, `string-join' returns the empty string, not nil.

Closes #434.

1 files changed, 3 insertions, 1 deletions

diff --git a/lisp/transient.el b/lisp/transient.el
index 9ca41b6..eda4265 100644
--- a/lisp/transient.el
+++ b/lisp/transient.el
@@ -3986,7 +3986,9 @@ it\", in which case it is pointless to preserve history.)"
              (reader (oref obj reader))
              (choices (if (functionp choices) (funcall choices) choices))
              (prompt (transient-prompt obj))
-             (value (if multi-value (string-join value ",") value))
+             (value (if (and multi-value value)
+                        (string-join value ",")
+                      value))
              (history-key (or (oref obj history-key)
                               (oref obj command)))
              (transient--history (alist-get history-key transient-history))