master 07fb8d284f: Don't put trailing optional nil values into `command-history'

[Lars Ingebrigtsen]

branch: master
commit 07fb8d284f8d08f79bb65e764b39180e2b974761
Author: Lars Ingebrigtsen <larsi@gnus.org>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Don't put trailing optional nil values into `command-history'
    
    * src/callint.c (fix_command): Don't put trailing optional nil
    values into `command-history' (bug#45333).
---
 src/callint.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/src/callint.c b/src/callint.c
index 92bfaf8d39..8283c61da6 100644
--- a/src/callint.c
+++ b/src/callint.c
@@ -170,7 +170,7 @@ check_mark (bool for_region)
    of VALUES to do its job.  */
 
 static void
-fix_command (Lisp_Object input, Lisp_Object values)
+fix_command (Lisp_Object input, Lisp_Object function, Lisp_Object values)
 {
   /* FIXME: Instead of this ugly hack, we should provide a way for an
      interactive spec to return an expression/function that will re-build the
@@ -230,6 +230,37 @@ fix_command (Lisp_Object input, Lisp_Object values)
            }
        }
     }
+
+  /* If the list contains a bunch of trailing nil values, and they are
+     optional, remove them from the list.  This makes navigating the
+     history less confusing, since it doesn't contain a lot of
+     parameters that aren't used.  */
+  if (CONSP (values))
+    {
+      Lisp_Object arity = Ffunc_arity (function);
+      /* We don't want to do this simplification if we have an &rest
+        function, because (cl-defun foo (a &optional (b 'zot)) ..)
+        etc.  */
+      if (FIXNUMP (XCAR (arity)) && FIXNUMP (XCDR (arity)))
+       {
+         Lisp_Object final = Qnil;
+         ptrdiff_t final_i = 0, i = 0;
+         for (Lisp_Object tail = values;
+              CONSP (tail);
+              tail = XCDR (tail), ++i)
+           {
+             if (!NILP (XCAR (tail)))
+               {
+                 final = tail;
+                 final_i = i;
+               }
+           }
+
+         /* Chop the trailing optional values.  */
+         if (final_i > 0 && final_i >= XFIXNUM (XCAR (arity)) - 1)
+           XSETCDR (final,  Qnil);
+       }
+    }
 }
 
 /* Helper function to call `read-file-name' from C.  */
@@ -340,7 +371,7 @@ invoke it (via an `interactive' spec that contains, for 
instance, an
             Make a copy of the list of values, for the command history,
             and turn them into things we can eval.  */
          Lisp_Object values = quotify_args (Fcopy_sequence (specs));
-         fix_command (input, values);
+         fix_command (input, function, values);
           call4 (intern ("add-to-history"), intern ("command-history"),
                  Fcons (function, values), Qnil, Qt);
        }