[Emacs-diffs] emacs-25 9d2b8e7: Fix 'this-command-keys' wrt prefix argument

[Eli Zaretskii]

branch: emacs-25
commit 9d2b8e768f2015a89f7609dedf7b28ea5e8123b5
Author: Eli Zaretskii <address@hidden>
Commit: Eli Zaretskii <address@hidden>

    Fix 'this-command-keys' wrt prefix argument
    
    * src/keyboard.c (command_loop_1): Restore the feature whereby C-u
    was part of this-command-keys, but not of this-single-command-keys.
    (Bug#22107)
    
    * lisp/simple.el (internal-echo-keystrokes-prefix): Add
    commentary about the function's return value.
---
 lisp/simple.el |    4 +++-
 src/keyboard.c |   13 ++++++++-----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/lisp/simple.el b/lisp/simple.el
index 17b9c91..9e0388e 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -3818,7 +3818,9 @@ see other processes running on the system, use 
`list-system-processes'."
 (setq prefix-command--last-echo nil)
 
 (defun internal-echo-keystrokes-prefix ()
-  ;; BEWARE: Called directly from the C code.
+  ;; BEWARE: Called directly from C code.
+  ;; If the return value is non-nil, it means we are in the middle of
+  ;; a command with prefix, such as a command invoked with prefix-arg.
   (if (not prefix-command--needs-update)
       prefix-command--last-echo
     (setq prefix-command--last-echo
diff --git a/src/keyboard.c b/src/keyboard.c
index 02bc7d2..928d849 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -1486,11 +1486,14 @@ command_loop_1 (void)
       if (!CONSP (last_command_event))
        kset_last_repeatable_command (current_kboard, Vreal_this_command);
 
-      this_command_key_count = 0;
-      this_single_command_key_start = 0;
-
-      if (current_kboard->immediate_echo
-         && !NILP (call0 (Qinternal_echo_keystrokes_prefix)))
+      /* Don't reset this_command_key_count if we've processed
+        prefix-arg.  */
+      if (NILP (call0 (Qinternal_echo_keystrokes_prefix)))
+       {
+         this_command_key_count = 0;
+         this_single_command_key_start = 0;
+       }
+      else if (current_kboard->immediate_echo)
        {
          current_kboard->immediate_echo = false;
          /* Refresh the echo message.  */