feat: display interactive-only note in helpful buffer

helpful.el

@@ -2270,6 +2270,11 @@ state of the current symbol."
        "\n\n"
        (helpful--format-obsolete-info helpful--sym helpful--callable-p)))
 
+    (when (helpful--interactive-only-info helpful--sym)
+      (insert
+       "\n\n"
+       (helpful--format-interactive-only-info helpful--sym)))
+
     (when (and helpful--callable-p
                (not (helpful--kbd-macro-p helpful--sym)))
       (helpful--insert-section-break)
@@ -2637,6 +2642,29 @@ For example, \"(some-func FOO &optional BAR)\"."
                     (use (format "; use `%s' instead." use))
                     (t ".")))))))
 
+(defun helpful--interactive-only-info (sym)
+  "If SYM has the `interactive-only' property, return its value.
+Return nil otherwise."
+  (when (symbolp sym)
+    (get sym 'interactive-only)))
+
+(defun helpful--format-interactive-only-info (sym)
+  "Format a note about SYM being interactive-only."
+  (let ((alternative (helpful--interactive-only-info sym)))
+    (helpful--format-docstring
+     (s-word-wrap
+      70
+      (cond
+       ((and (symbolp alternative) (not (eq alternative t)))
+        (format
+         "This command is for interactive use only; in Lisp code use `%s' instead."
+         alternative))
+       ((stringp alternative)
+        (format "This command is for interactive use only; %s"
+                alternative))
+       (t
+        "This command is for interactive use only."))))))
+
 (defun helpful--docstring (sym callable-p)
   "Get the docstring for SYM.
 Note that this returns the raw docstring, including \\=\\=

test/helpful-unit-test.el

@@ -23,6 +23,24 @@
   (declare (obsolete helpful "1.2.3"))
   nil)
 
+(defun helpful-test-interactive-only-sym ()
+  "A test command that is interactive-only with a symbol alternative."
+  (interactive)
+  nil)
+(put 'helpful-test-interactive-only-sym 'interactive-only 'helpful-test-fun-obsolete)
+
+(defun helpful-test-interactive-only-t ()
+  "A test command that is interactive-only with t."
+  (interactive)
+  nil)
+(put 'helpful-test-interactive-only-t 'interactive-only t)
+
+(defun helpful-test-interactive-only-str ()
+  "A test command that is interactive-only with a string."
+  (interactive)
+  nil)
+(put 'helpful-test-interactive-only-str 'interactive-only "use something else in Lisp code.")
+
 (defun test-foo ()
   "Docstring here."
   nil)
@@ -614,6 +632,29 @@ associated a lambda with a keybinding."
     (should
      (equal info "This function is obsolete since 1.2.3; use helpful instead."))))
 
+(ert-deftest helpful--interactive-only-symbol ()
+  "Test display of interactive-only with symbol alternative."
+  (let ((info (helpful--format-interactive-only-info
+               'helpful-test-interactive-only-sym)))
+    (should
+     (equal info
+            "This command is for interactive use only; in Lisp code use\nhelpful-test-fun-obsolete instead."))))
+
+(ert-deftest helpful--interactive-only-t ()
+  "Test display of interactive-only with t."
+  (let ((info (helpful--format-interactive-only-info
+               'helpful-test-interactive-only-t)))
+    (should
+     (equal info "This command is for interactive use only."))))
+
+(ert-deftest helpful--interactive-only-string ()
+  "Test display of interactive-only with string."
+  (let ((info (helpful--format-interactive-only-info
+               'helpful-test-interactive-only-str)))
+    (should
+     (equal info
+            "This command is for interactive use only; use something else in Lisp\ncode."))))
+
 (ert-deftest helpful--keymap-keys--sparse ()
   (let* ((parent-keymap (make-sparse-keymap))
          (keymap (make-sparse-keymap)))