Merge from origin/emacs-27

f3b62b6c62 (origin/emacs-27) Avoid crashes in regex-emacs.c due to GC
175c61c18b Fix "C-u M-!" when 'shell-command-dont-erase-buffer' is no...
6b297519b5 Fix cl-most-positive-float doc typo
c36c5a3ded ; lisp/ldefs-boot.el: Update.
3876a60569 Fix a typo in calculator.el
9e832ba91b * lisp/erc/erc.el: Add URL to the new ERC page on the Emac...

# Conflicts:
#	etc/NEWS

4 files changed, 28 insertions, 28 deletions

diff --git a/lisp/calculator.el b/lisp/calculator.el
index c1af26ffcc0..6996990814d 100644
--- a/lisp/calculator.el
+++ b/lisp/calculator.el
@@ -1622,7 +1622,7 @@ To use this, apply a binary operator (evaluate it), then call this."
     (overflow-error
      ;; X and Y must be integers, as expt silently returns floating-point
      ;; infinity on floating-point overflow.
-     (if (or (natnump x) (zerop (logand x 1)))
+     (if (or (natnump x) (zerop (logand y 1)))
          1.0e+INF
        -1.0e+INF))))
 
diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index cc5226bf6ed..cfde84e19aa 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -33,17 +33,8 @@
 ;;; Commentary:
 
 ;; ERC is a powerful, modular, and extensible IRC client for Emacs.
-
-;; For more information, see the following URLs:
-;; * https://sv.gnu.org/projects/erc/
-;; * https://www.emacswiki.org/emacs/ERC
-
-
-
-;; As of 2006-06-13, ERC development is now hosted on Savannah
-;; (https://sv.gnu.org/projects/erc).  I invite everyone who wants to
-;; hack on it to contact me <mwolson@gnu.org> in order to get write
-;; access to the shared Arch archive.
+;; For more information, visit the ERC page at
+;; <https://www.gnu.org/software/emacs/erc.html>.
 
 ;; Configuration:
 
@@ -75,12 +66,12 @@
 (eval-when-compile (require 'subr-x))
 
 (defvar erc-official-location
-  "https://www.emacswiki.org/emacs/ERC (mailing list: emacs-erc@gnu.org)"
+  "https://www.gnu.org/software/emacs/erc.html (mailing list: emacs-erc@gnu.org)"
   "Location of the ERC client on the Internet.")
 
 (defgroup erc nil
   "Emacs Internet Relay Chat client."
-  :link '(url-link "https://www.emacswiki.org/emacs/ERC")
+  :link '(url-link "https://www.gnu.org/software/emacs/erc.html")
   :link '(custom-manual "(erc) Top")
   :prefix "erc-"
   :group 'applications)
diff --git a/lisp/ldefs-boot.el b/lisp/ldefs-boot.el
index 10dc78d6288..e1f238c7d89 100644
--- a/lisp/ldefs-boot.el
+++ b/lisp/ldefs-boot.el
@@ -27873,7 +27873,7 @@ Directory for additional secondary Rmail files.")
 
 (custom-autoload 'rmail-secondary-file-directory "rmail" t)
 
-(defvar rmail-secondary-file-regexp (purecopy "\\.xmail$") "\
+(defvar rmail-secondary-file-regexp (purecopy "\\.xmail\\'") "\
 Regexp for which files are secondary Rmail files.")
 
 (custom-autoload 'rmail-secondary-file-regexp "rmail" t)
diff --git a/lisp/simple.el b/lisp/simple.el
index abf5ee26251..8bc84a9dfa0 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -3474,20 +3474,22 @@ This affects `shell-command' and `async-shell-command'."
   :version "27.1")
 
 (defcustom shell-command-dont-erase-buffer nil
-  "Control if the output buffer is erased before the command.
+  "Whether to erase the output buffer before executing shell command.
 
 A nil value erases the output buffer before execution of the
 shell command, except when the output buffer is the current one.
 
 The value `erase' ensures the output buffer is erased before
-execution of the shell command.
+execution of the shell command even if it is the current buffer.
 
-Other non-nil values prevent the output buffer from being erased and
-set the point after execution of the shell command.
+Other non-nil values prevent the output buffer from being erased; they
+also reposition point in the shell output buffer after execution of the
+shell command, except when the output buffer is the current buffer.
 
-The value `beg-last-out' sets point at the beginning of the output,
-`end-last-out' sets point at the end of the buffer, `save-point'
-restores the buffer position before the command."
+The value `beg-last-out' sets point at the beginning of the last
+output, `end-last-out' sets point at the end of the last output,
+and `save-point' restores the buffer position as it was before the
+shell command."
   :type '(choice
           (const :tag "Erase output buffer if not the current one" nil)
           (const :tag "Always erase output buffer" erase)
@@ -3517,9 +3519,12 @@ See `shell-command-dont-erase-buffer'."
     ;; if some text has a non-nil read-only property,
     ;; which comint sometimes adds for prompts.
     (setq pos
-          (cond ((eq sym 'save-point) (point))
-                ((eq sym 'beg-last-out) (point-max))
-                ;;((not sym)
+          (cond ((eq sym 'save-point)
+                 (if (not output-to-current-buffer)
+                     (point)))
+                ((eq sym 'beg-last-out)
+                 (if (not output-to-current-buffer)
+                     (point-max)))
                 ((or (eq sym 'erase)
                      (and (null sym) (not output-to-current-buffer)))
                  (let ((inhibit-read-only t))
@@ -3634,10 +3639,15 @@ says to put the output in some other buffer.
 If OUTPUT-BUFFER is a buffer or buffer name, erase that buffer
 and insert the output there; a non-nil value of
 `shell-command-dont-erase-buffer' prevents the buffer from being
-erased.  If OUTPUT-BUFFER is not a buffer and not nil, insert the
+erased.  If OUTPUT-BUFFER is not a buffer and not nil (which happens
+interactively when the prefix argument is given), insert the
 output in current buffer after point leaving mark after it.  This
 cannot be done asynchronously.
 
+The user option `shell-command-dont-erase-buffer', which see, controls
+whether the output buffer is erased and where to put point after
+the shell command.
+
 If the command terminates without error, but generates output,
 and you did not specify \"insert it in the current buffer\",
 the output can be displayed in the echo area or in its buffer.
@@ -3725,8 +3735,7 @@ impose the use of a shell (with its need to quote arguments)."
             ;; because we inserted text.
             (goto-char (prog1 (mark t)
                          (set-marker (mark-marker) (point)
-                                     (current-buffer))))
-            (shell-command-set-point-after-cmd))
+                                     (current-buffer)))))
         ;; Output goes in a separate buffer.
         ;; Preserve the match data in case called from a program.
         ;; FIXME: It'd be ridiculous for an Elisp function to call