Fix a small incompatibility in ibuffer

Translate nil values from column functions to the empty string, so that
subsequent calls to string-width don't signal an error (Bug#26317).
* lisp/ibuffer.el (ibuffer-compile-format): If a column function returns
nil, treat it like the empty string.

diff --git a/lisp/ibuffer.el b/lisp/ibuffer.el
index 66916b2bca1586c0755dd617ef56c0dfef8b1aa2..c83c21315a1c9535431467216c3e1bcdb9d5728a 100644 (file)
--- a/lisp/ibuffer.el
+++ b/lisp/ibuffer.el
@@ -1689,7 +1689,7 @@ If point is on a group name, this function operates on that group."
                    ;; generate a call to the column function.
                    (ibuffer-aif (assq sym ibuffer-inline-columns)
                        (nth 1 it)
-                     `(,sym buffer mark)))
+                     `(or (,sym buffer mark) "")))
                   ;; You're not expected to understand this.  Hell, I
                   ;; don't even understand it, and I wrote it five
                   ;; minutes ago.