Replace the error message with a nil return.

verilog-align-ports.el

@@ -67,8 +67,7 @@
 
 (defun verilog-align-ports--bounds ()
   (save-excursion
-    (unless (verilog-align-ports--line-port-p (line-beginning-position))
-      (user-error "Point is not on a port declaration line"))
+    (and (verilog-align-ports--line-port-p (line-beginning-position))
          (let ((start (line-beginning-position))
                (end nil))
            (while (and (not (bobp))
@@ -84,7 +83,7 @@
                         (line-beginning-position)))
              (forward-line 1))
            (setq end (line-beginning-position))
-      (cons start end))))
+           (cons start end)))))
 
 (defun verilog-align-ports--collect (start end)
   (let (entries)
@@ -169,14 +168,15 @@
 (defun verilog-align-ports ()
   "Align SystemVerilog port declarations around point."
   (interactive)
-  (let* ((bounds (verilog-align-ports--bounds))
-         (start (car bounds))
+  (let ((bounds (verilog-align-ports--bounds)))
+    (and bounds
+         (let* ((start (car bounds))
                 (end (cdr bounds))
                 (entries (verilog-align-ports--collect start end)))
-    (when (null entries)
-      (user-error "No port declarations found"))
+           (and entries
                 (let ((lines (verilog-align-ports--format-lines entries)))
-      (verilog-align-ports--apply start lines))))
+                  (verilog-align-ports--apply start lines)
+                  t))))))
 
 (provide 'verilog-align-ports)