2 files changed, 14 insertions, 4 deletions

diff --git a/etc/NEWS b/etc/NEWS
index c9fb2d48c19..4f49d2a6e44 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2830,8 +2830,8 @@ predicate (replacing 'so-long-detected-long-line-p').
 
 ---
 *** 'so-long-threshold' and 'so-long-max-lines' have been raised to
-10000 bytes and 500 lines respectively, to reduce the likelihood
-of false-positives when 'global-so-long-mode' is enabled.  The latter
+10000 bytes and 500 lines respectively, to reduce the likelihood of
+false-positives when 'global-so-long-mode' is enabled.  The latter
 value is now only used by the old predicate, as the new predicate
 knows the longest line in the entire buffer.
 
diff --git a/lisp/so-long.el b/lisp/so-long.el
index b1a3de1f725..829afd63eab 100644
--- a/lisp/so-long.el
+++ b/lisp/so-long.el
@@ -535,6 +535,10 @@ the `so-long-predicate' function is `so-long-statistics-excessive-p'."
 (defcustom so-long-max-lines 500
   "Number of non-blank, non-comment lines to test for excessive length.
 
+This option normally has no effect in Emacs versions >= 28.1, as the default
+`so-long-predicate' sees the entire buffer.  Older versions of Emacs still make
+use of this option.
+
 If nil then all lines will be tested, until either a long line is detected,
 or the end of the buffer is reached.
 
@@ -549,6 +553,10 @@ See `so-long-detected-long-line-p' for details."
 (defcustom so-long-skip-leading-comments t
   "Non-nil to ignore all leading comments and whitespace.
 
+This option normally has no effect in Emacs versions >= 28.1, as the default
+`so-long-predicate' sees the entire buffer.  Older versions of Emacs still make
+use of this option.
+
 If the file begins with a shebang (#!), this option also causes that line to be
 ignored even if it doesn't match the buffer's comment syntax, to ensure that
 comments following the shebang will be ignored.
@@ -613,8 +621,10 @@ Only called if the major mode is a member of `so-long-target-modes'.
 The specified function will be called with no arguments.  If it returns non-nil
 then `so-long' will be invoked.
 
-Defaults to `so-long-statistics-excessive-p' starting from Emacs 28, or
-`so-long-detected-long-line-p' in earlier versions."
+Defaults to `so-long-statistics-excessive-p' starting from Emacs 28.1, or
+`so-long-detected-long-line-p' in earlier versions.
+
+Note that `so-long-statistics-excessive-p' requires Emacs 28.1 or later."
   :type '(radio (const so-long-statistics-excessive-p)
                 (const so-long-detected-long-line-p)
                 (function :tag "Custom function"))