bug#38796-lossage-limit e13fd1f 3/4: Revert "Allow disable the record of keystrokes (lossage)"

[Tino Calancha]

branch: bug#38796-lossage-limit
commit e13fd1fc373b35f510b70998bfddbb7af5989912
Author: Tino Calancha <tino.calancha@gmail.com>
Commit: Tino Calancha <tino.calancha@gmail.com>

    Revert "Allow disable the record of keystrokes (lossage)"
    
    This reverts commit a60a05994aff16bc27f153ea8f765e15b92f21be.
---
 doc/emacs/help.texi        | 10 ++--------
 etc/NEWS                   |  3 +--
 lisp/cus-start.el          |  6 +-----
 src/keyboard.c             | 11 +++++------
 test/src/keyboard-tests.el |  2 +-
 5 files changed, 10 insertions(+), 22 deletions(-)

diff --git a/doc/emacs/help.texi b/doc/emacs/help.texi
index 69ea967..e2c0dc6 100644
--- a/doc/emacs/help.texi
+++ b/doc/emacs/help.texi
@@ -569,14 +569,8 @@ use @kbd{C-h l} (@code{view-lossage}).  @kbd{C-h l} 
displays your last
 input keystrokes and the commands they invoked.  By default, Emacs
 stores the last 300 events; if you wish, you can change this number
 with the option @code{lossage-limit}.
-If you see commands that you are not familiar with, you can use @kbd{C-h k}
-or @kbd{C-h f} to find out what they do.
-If you don't like that Emacs saves your keystrokes, then you can
-set @code{lossage-limit} equal to 1; such a value effectively disables the
-record of the keystrokes.  Please, do not set this option with @code{setq}
-neither let-bind it; that will likely crash Emacs.  Use instead the
-customization menu, which also updates the internal structure holding
-the keystrokes.
+If you see commands that you are not familiar with, you can use @kbd{C-h k} or
+@kbd{C-h f} to find out what they do.
 
 @kindex C-h e
 @findex view-echo-area-messages
diff --git a/etc/NEWS b/etc/NEWS
index 1777617..da204c5 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -72,8 +72,7 @@ useful on systems such as FreeBSD which ships only with 
"etc/termcap".
 
 +++
 ** The new option 'lossage-limit' controls the maximum number
-of keystrokes and commands recorded.  The value 1 disables
-the record of keystrokes.
+of keystrokes and commands recorded.
 
 ** Support for '(box . SIZE)' 'cursor-type'.
 By default, 'box' cursor always has a filled box shape.  But if you
diff --git a/lisp/cus-start.el b/lisp/cus-start.el
index bd4ff3a..1ebf554 100644
--- a/lisp/cus-start.el
+++ b/lisp/cus-start.el
@@ -352,11 +352,7 @@ Leaving \"Default\" unchecked is equivalent with 
specifying a default of
             ;; indent.c
             (indent-tabs-mode indent boolean)
             ;; keyboard.c
-             (lossage-limit keyboard
-                            (choice (const :tag "Do not record keystrokes" 1)
-                                    integer)
-                            "28.1"
-                            :standard 300
+             (lossage-limit keyboard integer "28.1"
                             :set (lambda (_ val) (update-lossage-limit val)))
             (meta-prefix-char keyboard character)
             (auto-save-interval auto-save integer)
diff --git a/src/keyboard.c b/src/keyboard.c
index 9af1b9b..a4d27c9 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -103,6 +103,8 @@ static KBOARD *all_kboards;
 /* True in the single-kboard state, false in the any-kboard state.  */
 static bool single_kboard;
 
+#define MIN_NUM_RECENT_KEYS (100)
+
 /* Index for storing next element into recent_keys.  */
 static int recent_keys_index;
 
@@ -10442,7 +10444,7 @@ usage: (update-lossage-limit ARG)  */)
     user_error ("Value must be a positive integer");
   int osize = ASIZE (recent_keys);
   eassert (lossage_limit == osize);
-  int min_size = 1;
+  int min_size = MIN_NUM_RECENT_KEYS;
   int new_size = XFIXNAT (arg);
 
   if (new_size == osize)
@@ -11747,11 +11749,8 @@ call from Lisp the following expression:
 
   (update-lossage-limit new-limit)
 
-That takes care of both, the variable and the internal vector.
-
-Security note: The value 1 makes impossible to recover a typed string
-with `view-lossage'.*/);
-  lossage_limit = 300;
+That takes care of both, the variable and the internal vector.*/);
+  lossage_limit = 3 * MIN_NUM_RECENT_KEYS;
 
   recent_keys = make_nil_vector (lossage_limit);
   staticpro (&recent_keys);
diff --git a/test/src/keyboard-tests.el b/test/src/keyboard-tests.el
index 4541c38..017d239 100644
--- a/test/src/keyboard-tests.el
+++ b/test/src/keyboard-tests.el
@@ -38,7 +38,7 @@
     (update-lossage-limit val)
     (should (= val lossage-limit)))
   (let ((current-limit lossage-limit))
-    (should-error (update-lossage-limit 0))
+    (should-error (update-lossage-limit 5))
     (should-error (update-lossage-limit "200"))
     (should (= lossage-limit current-limit))))