Merge from origin/emacs-26

255ba01148 Fix handling of nil PRED2 arg for completion-table-with-pr...
949b70a7d8 ; Minor comment copyedit in window.c
20f9bf30f0 Describe Lao rendering problem
3d61657694 Fix docstring of arabic-shaper-ZWNJ-handling
db949166ec Handle single-line comments correctly (Bug#26049)
795bb233a5 * test/lisp/net/tramp-tests.el (tramp-test16-file-expand-w...
ba00ea7d0d * etc/PROBLEMS: Add URL to relevant issues for xterm+evil bug
4a6015811e ; In text.texi fix typo spotted by Štěpán Němec
93cd8415b2 Document new treatment of 'comment-auto-fill-only-comments'
ca2d94ba61 Do not load Tramp unless `tramp-mode' is non-nil
709478eaa8 Prefer `customize-set-variable' in tramp.texi
5d36f2227f Fix last change in hscroll_window_tree
72d07d1950 Ediff: add some missing documentation
18af404ef3 Support python virtualenv on w32 (Bug#24464)
efd0371c23 Improve dired deletion error handling (Bug#28797)
5d744e032f Don't replace user input when completion prefix is empty (...
ec6cf35c5f ; Describe xt-mouse problems with Evil mode
c572e1f329 Return non-nil from gnutls-available-p under GnuTLS 2.x
a2cc6d74c5 Fix Flymake help-echo functions across windows (bug#29142)
58bb3462ee Add tests for Flymake backends for Ruby and Perl
58e742b21d Add a Flymake backend for Perl
9dee764165 Add a Flymake backend for Ruby
3ad712ebc9 Add a Flymake backend for Python (bug#28808)
8db2b3a79b Allow "%" in Tramp host names
8c50842790 ; Fix typo in test/file-organization.org
00fa4449cd ; Fix typo
918a2dda07 Use hybrid malloc for FreeBSD (Bug#28308)
725ab635d9 Add html-, mhtml- and python-mode support to semantic symref
369da28702 Improve documentation of 'window-scroll-functions'
93818eed8a Fix subtle problems in tabulated-list-mode with line numbers
1f1de8e872 Make gdb-non-stop-setting default to nil on MS-Windows
680e8e119b Fix gdb-mi prompt after "attach PID" command
ff33074546 Fix doc string of 'window-configuration-change-hook'
787b75ad71 Improve documentation of window hooks
d9be8704ae Fix hscroll suspension after cursor motion
6f43d29d29 ; * CONTRIBUTE, admin/make-tarball.txt: Doc tweaks re 'ema...
a0d30d6369 Introduce a function to CC Mode which displays the current...
383abc8898 ; Fix some comment typos
b02c2714c3 Fix typos in ediff-wind.el
4f38bdec74 Examine tex-chktex--process in the correct buffer
94b490529a * nt/INSTALL.W64: Update to current mingw64 install instru...
c25113d4ac Don't resignal errors in flymake-diag-region
e950f329c0 New xref-quit-and-goto-xref command bound to TAB (bug#28814)
5d34e1b288 Allow split-window-sensibly to split threshold in further ...
2a973edeac Honor window-switching intents in xref-find-definitions (b...
78e9065e9f * lisp/emacs-lisp/generator.el (iter-do): Add a debug decl...
caa63cc96c * lisp/progmodes/flymake.el (flymake-start): Fix dead buff...
9f4f130b79 Fix buffer name comparison in async shell-command

# Conflicts:
#	etc/NEWS
#	lisp/vc/ediff-wind.el

28 files changed, 594 insertions, 143 deletions

diff --git a/lisp/calc/calcalg2.el b/lisp/calc/calcalg2.el
index 53e02572064..48446c3c4c5 100644
--- a/lisp/calc/calcalg2.el
+++ b/lisp/calc/calcalg2.el
@@ -2354,7 +2354,7 @@
 
 ;; The variables math-solve-lhs, math-solve-rhs and math-try-solve-sign
 ;; are local to math-try-solve-for,  but are used by math-try-solve-prod.
-;; (math-solve-lhs and math-solve-rhs are is also local to
+;; (math-solve-lhs and math-solve-rhs are also local to
 ;; math-decompose-poly, but used by math-solve-poly-funny-powers.)
 (defvar math-solve-lhs)
 (defvar math-solve-rhs)
diff --git a/lisp/cedet/semantic/symref/grep.el b/lisp/cedet/semantic/symref/grep.el
index bc19cd30c45..0b263d8cc2d 100644
--- a/lisp/cedet/semantic/symref/grep.el
+++ b/lisp/cedet/semantic/symref/grep.el
@@ -38,16 +38,22 @@
   (
    )
   "A symref tool implementation using grep.
-This tool uses EDE to find he root of the project, then executes
-find-grep in the project.  The output is parsed for hits
-and those hits returned.")
+This tool uses EDE to find the root of the project, then executes
+find-grep in the project.  The output is parsed for hits and
+those hits returned.")
 
 (defvar semantic-symref-filepattern-alist
   '((c-mode "*.[ch]")
     (c++-mode "*.[chCH]" "*.[ch]pp" "*.cc" "*.hh")
-    (html-mode "*.s?html" "*.php")
+    (html-mode "*.html" "*.shtml" "*.php")
+    (mhtml-mode "*.html" "*.shtml" "*.php") ; FIXME: remove
+                                            ; duplication of
+                                            ; HTML-related patterns.
+                                            ; Maybe they belong in the
+                                            ; major mode definition?
     (ruby-mode "*.r[bu]" "*.rake" "*.gemspec" "*.erb" "*.haml"
                "Rakefile" "Thorfile" "Capfile" "Guardfile" "Vagrantfile")
+    (python-mode "*.py" "*.pyi" "*.pyw")
     (perl-mode "*.pl" "*.PL")
     (cperl-mode "*.pl" "*.PL")
     (lisp-interaction-mode "*.el" "*.ede" ".emacs" "_emacs")
@@ -58,7 +64,7 @@ See find -name man page for format.")
 (defun semantic-symref-derive-find-filepatterns (&optional mode)
   ;; FIXME: This should be moved to grep.el, where it could be used
   ;; for "C-u M-x grep" as well.
-  "Derive a list of file patterns for the current buffer.
+  "Derive a list of file (glob) patterns for the current buffer.
 Looks first in `semantic-symref-filepattern-alist'.  If it is not
 there, it then looks in `auto-mode-alist', and attempts to derive something
 from that.
@@ -78,7 +84,7 @@ Optional argument MODE specifies the `major-mode' to test."
         (error "Customize `semantic-symref-filepattern-alist' for %S"
                major-mode)
       (let ((args `("-name" ,(car pat))))
-        (if (null (cdr args))
+        (if (null (cdr pat))
             args
           `("(" ,@args
             ,@(mapcan (lambda (s) `("-o" "-name" ,s)) pat)
@@ -149,7 +155,7 @@ This shell should support pipe redirect syntax."
                          (oref tool searchfor))
                         (t
                          ;; Can't use the word boundaries: Grep
-                         ;; doesn't always agrees with the language
+                         ;; doesn't always agree with the language
                          ;; syntax on those.
                          (format "\\(^\\|\\W\\)%s\\(\\W\\|$\\)"
                                  (oref tool searchfor)))))
diff --git a/lisp/dired.el b/lisp/dired.el
index 46918180f12..0abb521cc5b 100644
--- a/lisp/dired.el
+++ b/lisp/dired.el
@@ -3146,7 +3146,7 @@ non-empty directories is allowed."
                        #'dired-delete-entry fn))
                   (quit (throw '--delete-cancel (message "OK, canceled")))
                   (error ;; catch errors from failed deletions
-                   (dired-log "%s\n" err)
+                   (dired-log "%s: %s\n" (car err) (error-message-string err))
                    (setq failures (cons (car (car l)) failures)))))
               (setq l (cdr l)))
             (if (not failures)
diff --git a/lisp/emacs-lisp/generator.el b/lisp/emacs-lisp/generator.el
index 410e4edcc92..ef6cfba420c 100644
--- a/lisp/emacs-lisp/generator.el
+++ b/lisp/emacs-lisp/generator.el
@@ -718,7 +718,8 @@ is blocked."
   "Loop over values from an iterator.
 Evaluate BODY with VAR bound to each value from ITERATOR.
 Return the value with which ITERATOR finished iteration."
-  (declare (indent 1))
+  (declare (indent 1)
+           (debug ((symbolp form) body)))
   (let ((done-symbol (cps--gensym "iter-do-iterator-done"))
         (condition-symbol (cps--gensym "iter-do-condition"))
         (it-symbol (cps--gensym "iter-do-iterator"))
diff --git a/lisp/emacs-lisp/tabulated-list.el b/lisp/emacs-lisp/tabulated-list.el
index 73ddadfb805..3889ba8e587 100644
--- a/lisp/emacs-lisp/tabulated-list.el
+++ b/lisp/emacs-lisp/tabulated-list.el
@@ -603,7 +603,16 @@ With a numeric prefix argument N, sort the Nth column."
       (let ((lnum-width (tabulated-list-line-number-width)))
         (when (not (= tabulated-list--current-lnum-width lnum-width))
           (setq-local tabulated-list--current-lnum-width lnum-width)
-          (tabulated-list-revert)))))
+          (tabulated-list-init-header)))))
+
+(defun tabulated-list-window-scroll-function (window _start)
+  (if display-line-numbers
+      (let ((lnum-width
+             (with-selected-window window
+               (line-number-display-width 'columns))))
+        (when (not (= tabulated-list--current-lnum-width lnum-width))
+          (setq-local tabulated-list--current-lnum-width lnum-width)
+          (tabulated-list-init-header)))))
 
 ;;; The mode definition:
 
@@ -654,7 +663,9 @@ as the ewoc pretty-printer."
   ;; the line-number width needs to change due to scrolling.
   (setq-local tabulated-list--current-lnum-width 0)
   (add-hook 'pre-redisplay-functions
-            #'tabulated-list-watch-line-number-width nil t))
+            #'tabulated-list-watch-line-number-width nil t)
+  (add-hook 'window-scroll-functions
+            #'tabulated-list-window-scroll-function nil t))
 
 (put 'tabulated-list-mode 'mode-class 'special)
 
diff --git a/lisp/language/misc-lang.el b/lisp/language/misc-lang.el
index cbb581fd19f..c1aa79cae45 100644
--- a/lisp/language/misc-lang.el
+++ b/lisp/language/misc-lang.el
@@ -87,9 +87,7 @@ If the value is `absorb', ZWNJ is absorbed into the previous
 grapheme cluster, and not displayed.
 
 If the value is `as-space', the glyph is displayed by a
-thin (i.e. 1-dot width) space.
-
-Customizing the value takes effect when you start Emacs next time."
+thin (i.e. 1-dot width) space."
   :group 'mule
   :version "26.1"
   :type '(choice
diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index c3f77afae60..77fddc3436d 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -392,7 +392,7 @@ obeys predicates."
                                   (and (funcall pred1 x) (funcall pred2 x)))))
         ;; If completion failed and we're not applying pred1 strictly, try
         ;; again without pred1.
-        (and (not strict) pred1 pred2
+        (and (not strict) pred1
              (complete-with-action action table string pred2))))))
 
 (defun completion-table-in-turn (&rest tables)
diff --git a/lisp/net/tramp-gvfs.el b/lisp/net/tramp-gvfs.el
index 51d24cbc1b0..709ea4670a8 100644
--- a/lisp/net/tramp-gvfs.el
+++ b/lisp/net/tramp-gvfs.el
@@ -1292,7 +1292,8 @@ file-notify events."
             (when (and user domain)
               (setq user (concat domain ";" user)))
             (url-parse-make-urlobj
-             method (and user (url-hexify-string user)) nil host
+             method (and user (url-hexify-string user))
+             nil (and host (url-hexify-string host))
              (if (stringp port) (string-to-number port) port)
              (and localname (url-hexify-string localname)) nil nil t))
         (url-parse-make-urlobj
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index a23da848112..15868bd2e8f 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -818,7 +818,7 @@ Used in `tramp-make-tramp-file-name'.")
   "Regexp matching delimiter between user and host names.
 Derived from `tramp-postfix-user-format'.")
 
-(defconst tramp-host-regexp "[a-zA-Z0-9_.-]+"
+(defconst tramp-host-regexp "[a-zA-Z0-9_.%-]+"
   "Regexp matching host names.")
 
 (defconst tramp-prefix-ipv6-format-alist
@@ -2305,8 +2305,10 @@ Falls back to normal file name handler if no Tramp file name handler exists."
 ;;;###autoload
 (progn (defun tramp-autoload-file-name-handler (operation &rest args)
   "Load Tramp file name handler, and perform OPERATION."
-  (let ((default-directory temporary-file-directory))
-    (load "tramp" 'noerror 'nomessage))
+  (if tramp-mode
+      (let ((default-directory temporary-file-directory))
+        (load "tramp" 'noerror 'nomessage))
+    (tramp-unload-file-name-handlers))
   (apply operation args)))
 
 ;; `tramp-autoload-file-name-handler' must be registered before
@@ -2422,12 +2424,13 @@ Add operations defined in `HANDLER-alist' to `tramp-file-name-handler'."
       (equal (apply operation args) operation))))
 
 ;;;###autoload
-(defun tramp-unload-file-name-handlers ()
+(progn (defun tramp-unload-file-name-handlers ()
   "Unload Tramp file name handlers from `file-name-handler-alist'."
   (dolist (fnh '(tramp-file-name-handler
-                 tramp-completion-file-name-handler))
+                 tramp-completion-file-name-handler
+                 tramp-autoload-file-name-handler))
     (let ((a1 (rassq fnh file-name-handler-alist)))
-      (setq file-name-handler-alist (delq a1 file-name-handler-alist)))))
+      (setq file-name-handler-alist (delq a1 file-name-handler-alist))))))
 
 (add-hook 'tramp-unload-hook 'tramp-unload-file-name-handlers)
 
@@ -4631,9 +4634,6 @@ Only works for Bourne-like shells."
 (provide 'tramp)
 
 ;;; TODO:
-
-;; * In Emacs 21, `insert-directory' shows total number of bytes used
-;;   by the files in that directory.  Add this here.
 ;;
 ;; * Avoid screen blanking when hitting `g' in dired.  (Eli Tziperman)
 ;;
diff --git a/lisp/newcomment.el b/lisp/newcomment.el
index 2e644c3a99c..56ae14dee41 100644
--- a/lisp/newcomment.el
+++ b/lisp/newcomment.el
@@ -69,6 +69,9 @@
 
 ;;; Code:
 
+(eval-when-compile
+  (require 'subr-x))
+
 ;;;###autoload
 (defalias 'indent-for-comment 'comment-indent)
 ;;;###autoload
@@ -1141,6 +1144,9 @@ the region rather than at left margin."
 
           ;; make the leading and trailing lines if requested
           (when lines
+            ;; Trim trailing whitespace from cs if there's some.
+            (setq cs (string-trim-right cs))
+
             (let ((csce
                    (comment-make-extra-lines
                     cs ce ccs cce min-indent max-indent block)))
@@ -1211,7 +1217,7 @@ changed with `comment-style'."
            (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
                   (<= (point) end))
            (or block (not (string= "" comment-end)))
-           (or block (progn (goto-char beg) (search-forward "\n" end t)))))
+           (or block (progn (goto-char beg) (re-search-forward "$" end t)))))
 
     ;; don't add end-markers just because the user asked for `block'
     (unless (or lines (string= "" comment-end)) (setq block nil))
diff --git a/lisp/pcomplete.el b/lisp/pcomplete.el
index 745a813b758..2d2a8773bfe 100644
--- a/lisp/pcomplete.el
+++ b/lisp/pcomplete.el
@@ -772,7 +772,7 @@ this is `comint-dynamic-complete-functions'."
                 (setq c (cdr c)))
               (setq pcomplete-stub (substring common-stub 0 len)
                     pcomplete-autolist t)
-              (when (and begin (not pcomplete-show-list))
+              (when (and begin (> len 0) (not pcomplete-show-list))
                 (delete-region begin (point))
                 (pcomplete-insert-entry "" pcomplete-stub))
               (throw 'pcomplete-completions completions))
diff --git a/lisp/progmodes/cc-cmds.el b/lisp/progmodes/cc-cmds.el
index ca64b544200..2b663135932 100644
--- a/lisp/progmodes/cc-cmds.el
+++ b/lisp/progmodes/cc-cmds.el
@@ -1821,7 +1821,6 @@ the open-parenthesis that starts a defun; see `beginning-of-defun'."
   "Return the name of the current defun, or NIL if there isn't one.
 \"Defun\" here means a function, or other top level construct
 with a brace block."
-  (interactive)
   (c-save-buffer-state
       (beginning-of-defun-function end-of-defun-function
        where pos name-end case-fold-search)
@@ -2048,6 +2047,23 @@ with a brace block."
               (eq (char-after) ?\{)
               (cons (point-min) (point-max))))))))
 
+(defun c-display-defun-name (&optional arg)
+  "Display the name of the current CC mode defun and the position in it.
+With a prefix arg, push the name onto the kill ring too."
+  (interactive "P")
+  (save-restriction
+    (widen)
+    (c-save-buffer-state ((name (c-defun-name))
+                          (limits (c-declaration-limits t))
+                          (point-bol (c-point 'bol)))
+      (when name
+        (message "%s.  Line %s/%s." name
+                 (1+ (count-lines (car limits) point-bol))
+                 (count-lines (car limits) (cdr limits)))
+        (if arg (kill-new name))
+        (sit-for 3 t)))))
+(put 'c-display-defun-name 'isearch-scroll t)
+
 (defun c-mark-function ()
   "Put mark at end of the current top-level declaration or macro, point at beginning.
 If point is not inside any then the closest following one is
@@ -2092,7 +2108,6 @@ function does not require the declaration to contain a brace block."
 
 (defun c-cpp-define-name ()
   "Return the name of the current CPP macro, or NIL if we're not in one."
-  (interactive)
   (let (case-fold-search)
     (save-excursion
       (and c-opt-cpp-macro-define-start
diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index b0e5fe47a7c..f74e931a8bb 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -389,7 +389,8 @@ control).  See \"cc-mode.el\" for more info."
   ;;(define-key c-mode-base-map "\C-c\C-v"  'c-version)
   ;; (define-key c-mode-base-map "\C-c\C-y"  'c-toggle-hungry-state)  Commented out by ACM, 2005-11-22.
   (define-key c-mode-base-map "\C-c\C-w" 'c-subword-mode)
-  (define-key c-mode-base-map "\C-c\C-k" 'c-toggle-comment-style))
+  (define-key c-mode-base-map "\C-c\C-k" 'c-toggle-comment-style)
+  (define-key c-mode-base-map "\C-c\C-z" 'c-display-defun-name))
 
 ;; We don't require the outline package, but we configure it a bit anyway.
 (cc-bytecomp-defvar outline-level)
diff --git a/lisp/progmodes/cperl-mode.el b/lisp/progmodes/cperl-mode.el
index 1681922fa5a..e6ab8c4ea60 100644
--- a/lisp/progmodes/cperl-mode.el
+++ b/lisp/progmodes/cperl-mode.el
@@ -1896,7 +1896,9 @@ or as help on variables `cperl-tips', `cperl-problems',
   (if cperl-pod-here-scan
       (or cperl-syntaxify-by-font-lock
        (progn (or cperl-faces-init (cperl-init-faces-weak))
-              (cperl-find-pods-heres)))))
+              (cperl-find-pods-heres))))
+  ;; Setup Flymake
+  (add-hook 'flymake-diagnostic-functions 'perl-flymake nil t))
 
 ;; Fix for perldb - make default reasonable
 (defun cperl-db ()
diff --git a/lisp/progmodes/flymake-proc.el b/lisp/progmodes/flymake-proc.el
index f504a1c21a8..e28451d9417 100644
--- a/lisp/progmodes/flymake-proc.el
+++ b/lisp/progmodes/flymake-proc.el
@@ -82,7 +82,7 @@ Overrides `flymake-proc-allowed-file-name-masks'."
     ("\\.xml\\'" flymake-proc-xml-init)
     ("\\.html?\\'" flymake-proc-xml-init)
     ("\\.cs\\'" flymake-proc-simple-make-init)
-    ("\\.p[ml]\\'" flymake-proc-perl-init)
+    ;; ("\\.p[ml]\\'" flymake-proc-perl-init)
     ("\\.php[345]?\\'" flymake-proc-php-init)
     ("\\.h\\'" flymake-proc-master-make-header-init flymake-proc-master-cleanup)
     ("\\.java\\'" flymake-proc-simple-make-java-init flymake-proc-simple-java-cleanup)
diff --git a/lisp/progmodes/flymake.el b/lisp/progmodes/flymake.el
index 19dac81fe6d..0d200f01b34 100644
--- a/lisp/progmodes/flymake.el
+++ b/lisp/progmodes/flymake.el
@@ -342,7 +342,7 @@ region is invalid."
                 (let* ((beg (fallback-bol))
                        (end (fallback-eol beg)))
                   (cons beg end)))))))
-    (error (flymake-error "Invalid region line=%s col=%s" line col))))
+    (error (flymake-log :warning "Invalid region line=%s col=%s" line col))))
 
 (defvar flymake-diagnostic-functions nil
   "Special hook of Flymake backends that check a buffer.
@@ -522,11 +522,12 @@ associated `flymake-category' return DEFAULT."
         (flymake--fringe-overlay-spec
          (overlay-get ov 'bitmap)))
       (default-maybe 'help-echo
-        (lambda (_window _ov pos)
-          (mapconcat
-           #'flymake--diag-text
-           (flymake-diagnostics pos)
-           "\n")))
+        (lambda (window _ov pos)
+          (with-selected-window window
+            (mapconcat
+             #'flymake--diag-text
+             (flymake-diagnostics pos)
+             "\n"))))
       (default-maybe 'severity (warning-numeric-level :error))
       (default-maybe 'priority (+ 100 (overlay-get ov 'severity))))
     ;; Some properties can't be overridden.
@@ -603,8 +604,8 @@ not expected."
           (null expected-token))
         ;; should never happen
         (flymake-error "Unexpected report from stopped backend %s" backend))
-       ((and (not (eq expected-token token))
-             (not force))
+       ((not (or (eq expected-token token)
+                 force))
         (flymake-error "Obsolete report from backend %s with explanation %s"
                        backend explanation))
        ((eq :panic report-action)
@@ -744,8 +745,11 @@ Interactively, with a prefix arg, FORCE is t."
           ()
           (remove-hook 'post-command-hook #'start-post-command
                        nil)
-          (with-current-buffer buffer
-            (flymake-start (remove 'post-command deferred) force)))
+          ;; The buffer may have disappeared already, e.g. because of
+          ;; code like `(with-temp-buffer (python-mode) ...)'.
+          (when (buffer-live-p buffer)
+            (with-current-buffer buffer
+              (flymake-start (remove 'post-command deferred) force))))
          (start-on-display
           ()
           (remove-hook 'window-configuration-change-hook #'start-on-display
@@ -948,7 +952,7 @@ applied."
              (message
               "%s"
               (funcall (overlay-get target 'help-echo)
-                       nil nil (point)))))
+                       (selected-window) target (point)))))
           (interactive
            (user-error "No more Flymake errors%s"
                        (if filter
diff --git a/lisp/progmodes/gdb-mi.el b/lisp/progmodes/gdb-mi.el
index 28d1974893d..58552759b95 100644
--- a/lisp/progmodes/gdb-mi.el
+++ b/lisp/progmodes/gdb-mi.el
@@ -400,14 +400,22 @@ valid signal handlers.")
           (const   :tag "Unlimited" nil))
   :version "22.1")
 
-(defcustom gdb-non-stop-setting t
-  "When in non-stop mode, stopped threads can be examined while
+(defcustom gdb-non-stop-setting (not (eq system-type 'windows-nt))
+  "If non-nil, GDB sessions are expected to support the non-stop mode.
+When in the non-stop mode, stopped threads can be examined while
 other threads continue to execute.
 
+If this is non-nil, GDB will be sent the \"set non-stop 1\" command,
+and if that results in an error, the non-stop setting will be
+turned off automatically.
+
+On MS-Windows, this is off by default, because MS-Windows targets
+don't support the non-stop mode.
+
 GDB session needs to be restarted for this setting to take effect."
   :type 'boolean
   :group 'gdb-non-stop
-  :version "23.2")
+  :version "26.1")
 
 ;; TODO Some commands can't be called with --all (give a notice about
 ;; it in setting doc)
@@ -2188,7 +2196,10 @@ a GDB/MI reply message."
 
 (defun gdbmi-bnf-console-stream-output (c-string)
   "Handler for the console-stream-output GDB/MI output grammar rule."
-  (gdb-console c-string))
+  (gdb-console c-string)
+  ;; We've written to the GUD console, so we should print the prompt
+  ;; after the next result-class or async-class.
+  (setq gdb-first-done-or-error t))
 
 (defun gdbmi-bnf-target-stream-output (_c-string)
   "Handler for the target-stream-output GDB/MI output grammar rule."
diff --git a/lisp/progmodes/perl-mode.el b/lisp/progmodes/perl-mode.el
index 24b934ce6c2..8e7cd13088f 100644
--- a/lisp/progmodes/perl-mode.el
+++ b/lisp/progmodes/perl-mode.el
@@ -581,6 +581,73 @@ create a new comment."
         (match-string-no-properties 1))))
 
 
+;;; Flymake support
+(defcustom perl-flymake-command '("perl" "-w" "-c")
+  "External tool used to check Perl source code.
+This is a non empty list of strings, the checker tool possibly
+followed by required arguments.  Once launched it will receive
+the Perl source to be checked as its standard input."
+  :group 'perl
+  :type '(repeat string))
+
+(defvar-local perl--flymake-proc nil)
+
+;;;###autoload
+(defun perl-flymake (report-fn &rest _args)
+  "Perl backend for Flymake.  Launches
+`perl-flymake-command' (which see) and passes to its standard
+input the contents of the current buffer.  The output of this
+command is analysed for error and warning messages."
+  (unless (executable-find (car perl-flymake-command))
+    (error "Cannot find a suitable checker"))
+
+  (when (process-live-p perl--flymake-proc)
+    (kill-process perl--flymake-proc))
+
+  (let ((source (current-buffer)))
+    (save-restriction
+      (widen)
+      (setq
+       perl--flymake-proc
+       (make-process
+        :name "perl-flymake" :noquery t :connection-type 'pipe
+        :buffer (generate-new-buffer " *perl-flymake*")
+        :command perl-flymake-command
+        :sentinel
+        (lambda (proc _event)
+          (when (eq 'exit (process-status proc))
+            (unwind-protect
+                (if (with-current-buffer source (eq proc perl--flymake-proc))
+                    (with-current-buffer (process-buffer proc)
+                      (goto-char (point-min))
+                      (cl-loop
+                       while (search-forward-regexp
+                              "^\\(.+\\) at - line \\([0-9]+\\)"
+                              nil t)
+                       for msg = (match-string 1)
+                       for (beg . end) = (flymake-diag-region
+                                          source
+                                          (string-to-number (match-string 2)))
+                       for type =
+                       (if (string-match
+                            "\\(Scalar value\\|Useless use\\|Unquoted string\\)"
+                            msg)
+                           :warning
+                         :error)
+                       collect (flymake-make-diagnostic source
+                                                        beg
+                                                        end
+                                                        type
+                                                        msg)
+                       into diags
+                       finally (funcall report-fn diags)))
+                  (flymake-log :debug "Canceling obsolete check %s"
+                               proc))
+              (kill-buffer (process-buffer proc)))))))
+      (process-send-region perl--flymake-proc (point-min) (point-max))
+      (process-send-eof perl--flymake-proc))))
+
+
 (defvar perl-mode-hook nil
   "Normal hook to run when entering Perl mode.")
 
@@ -665,7 +732,9 @@ Turning on Perl mode runs the normal hook `perl-mode-hook'."
   ;; Setup outline-minor-mode.
   (setq-local outline-regexp perl-outline-regexp)
   (setq-local outline-level 'perl-outline-level)
-  (setq-local add-log-current-defun-function #'perl-current-defun-name))
+  (setq-local add-log-current-defun-function #'perl-current-defun-name)
+  ;; Setup Flymake
+  (add-hook 'flymake-diagnostic-functions #'perl-flymake nil t))
 
 ;; This is used by indent-for-comment
 ;; to decide how much to indent a comment in Perl code
diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 895117b9ee3..d4226e5ce7b 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -2113,20 +2113,25 @@ remote host, the returned value is intended for
 (defun python-shell-calculate-exec-path ()
   "Calculate `exec-path'.
 Prepends `python-shell-exec-path' and adds the binary directory
-for virtualenv if `python-shell-virtualenv-root' is set.  If
-`default-directory' points to a remote host, the returned value
-appends `python-shell-remote-exec-path' instead of `exec-path'."
+for virtualenv if `python-shell-virtualenv-root' is set - this
+will use the python interpreter from inside the virtualenv when
+starting the shell.  If `default-directory' points to a remote host,
+the returned value appends `python-shell-remote-exec-path' instead
+of `exec-path'."
   (let ((new-path (copy-sequence
                    (if (file-remote-p default-directory)
                        python-shell-remote-exec-path
-                     exec-path))))
+                     exec-path)))
+
+        ;; Windows and POSIX systems use different venv directory structures
+        (virtualenv-bin-dir (if (eq system-type 'windows-nt) "Scripts" "bin")))
     (python-shell--add-to-path-with-priority
      new-path python-shell-exec-path)
     (if (not python-shell-virtualenv-root)
         new-path
       (python-shell--add-to-path-with-priority
        new-path
-       (list (expand-file-name "bin" python-shell-virtualenv-root)))
+       (list (expand-file-name virtualenv-bin-dir python-shell-virtualenv-root)))
       new-path)))
 
 (defun python-shell-tramp-refresh-remote-path (vec paths)
@@ -5142,6 +5147,138 @@ returned as is."
   (ignore-errors (string-match regexp "") t))
 
 
+;;; Flymake integration
+
+(defgroup python-flymake nil
+  "Integration between Python and Flymake."
+  :group 'python
+  :link '(custom-group-link :tag "Flymake" flymake)
+  :version "26.1")
+
+(defcustom python-flymake-command '("pyflakes")
+  "The external tool that will be used to perform the syntax check.
+This is a non empty list of strings, the checker tool possibly followed by
+required arguments.  Once launched it will receive the Python source to be
+checked as its standard input.
+To use `flake8' you would set this to (\"flake8\" \"-\")."
+  :group 'python-flymake
+  :type '(repeat string))
+
+;; The default regexp accomodates for older pyflakes, which did not
+;; report the column number, and at the same time it's compatible with
+;; flake8 output, although it may be redefined to explicitly match the
+;; TYPE
+(defcustom python-flymake-command-output-pattern
+  (list
+   "^\\(?:<?stdin>?\\):\\(?1:[0-9]+\\):\\(?:\\(?2:[0-9]+\\):\\)? \\(?3:.*\\)$"
+   1 2 nil 3)
+  "Specify how to parse the output of `python-flymake-command'.
+The value has the form (REGEXP LINE COLUMN TYPE MESSAGE): if
+REGEXP matches, the LINE'th subexpression gives the line number,
+the COLUMN'th subexpression gives the column number on that line,
+the TYPE'th subexpression gives the type of the message and the
+MESSAGE'th gives the message text itself.
+
+If COLUMN or TYPE are nil or that index didn't match, that
+information is not present on the matched line and a default will
+be used."
+  :group 'python-flymake
+  :type '(list regexp
+               (integer :tag "Line's index")
+               (choice
+                (const :tag "No column" nil)
+                (integer :tag "Column's index"))
+               (choice
+                (const :tag "No type" nil)
+                (integer :tag "Type's index"))
+               (integer :tag "Message's index")))
+
+(defcustom python-flymake-msg-alist
+  '(("\\(^redefinition\\|.*unused.*\\|used$\\)" . :warning))
+  "Alist used to associate messages to their types.
+Each element should be a cons-cell (REGEXP . TYPE), where TYPE must be
+one defined in the variable `flymake-diagnostic-types-alist'.
+For example, when using `flake8' a possible configuration could be:
+
+  ((\"\\(^redefinition\\|.*unused.*\\|used$\\)\" . :warning)
+   (\"^E999\" . :error)
+   (\"^[EW][0-9]+\" . :note))
+
+By default messages are considered errors."
+  :group 'python-flymake
+  :type `(alist :key-type (regexp)
+                :value-type (symbol)))
+
+(defvar-local python--flymake-proc nil)
+
+(defun python--flymake-parse-output (source proc report-fn)
+  "Collect diagnostics parsing checker tool's output line by line."
+  (let ((rx (nth 0 python-flymake-command-output-pattern))
+        (lineidx (nth 1 python-flymake-command-output-pattern))
+        (colidx (nth 2 python-flymake-command-output-pattern))
+        (typeidx (nth 3 python-flymake-command-output-pattern))
+        (msgidx (nth 4 python-flymake-command-output-pattern)))
+    (with-current-buffer (process-buffer proc)
+      (goto-char (point-min))
+      (cl-loop
+       while (search-forward-regexp rx nil t)
+       for msg = (match-string msgidx)
+       for (beg . end) = (flymake-diag-region
+                          source
+                          (string-to-number
+                           (match-string lineidx))
+                          (and colidx
+                               (match-string colidx)
+                               (string-to-number
+                                (match-string colidx))))
+       for type = (or (and typeidx
+                           (match-string typeidx)
+                           (assoc-default
+                            (match-string typeidx)
+                            python-flymake-msg-alist
+                            #'string-match))
+                      (assoc-default msg
+                                     python-flymake-msg-alist
+                                     #'string-match)
+                      :error)
+       collect (flymake-make-diagnostic
+                source beg end type msg)
+       into diags
+       finally (funcall report-fn diags)))))
+
+(defun python-flymake (report-fn &rest _args)
+  "Flymake backend for Python.
+This backend uses `python-flymake-command' (which see) to launch a process
+that is passed the current buffer's content via stdin.
+REPORT-FN is Flymake's callback function."
+  (unless (executable-find (car python-flymake-command))
+    (error "Cannot find a suitable checker"))
+
+  (when (process-live-p python--flymake-proc)
+    (kill-process python--flymake-proc))
+
+  (let ((source (current-buffer)))
+    (save-restriction
+      (widen)
+      (setq python--flymake-proc
+            (make-process
+             :name "python-flymake"
+             :noquery t
+             :connection-type 'pipe
+             :buffer (generate-new-buffer " *python-flymake*")
+             :command python-flymake-command
+             :sentinel
+             (lambda (proc _event)
+               (when (eq 'exit (process-status proc))
+                 (unwind-protect
+                     (when (with-current-buffer source
+                             (eq proc python--flymake-proc))
+                       (python--flymake-parse-output source proc report-fn))
+                   (kill-buffer (process-buffer proc)))))))
+      (process-send-region python--flymake-proc (point-min) (point-max))
+      (process-send-eof python--flymake-proc))))
+
+
 (defun python-electric-pair-string-delimiter ()
   (when (and electric-pair-mode
              (memq last-command-event '(?\" ?\'))
@@ -5255,7 +5392,9 @@ returned as is."
   (make-local-variable 'python-shell-internal-buffer)
 
   (when python-indent-guess-indent-offset
-    (python-indent-guess-indent-offset)))
+    (python-indent-guess-indent-offset))
+
+  (add-hook 'flymake-diagnostic-functions #'python-flymake nil t))
 
 
 (provide 'python)
diff --git a/lisp/progmodes/ruby-mode.el b/lisp/progmodes/ruby-mode.el
index 0024957c39b..1f4aa6d9fbd 100644
--- a/lisp/progmodes/ruby-mode.el
+++ b/lisp/progmodes/ruby-mode.el
@@ -2253,6 +2253,68 @@ See `font-lock-syntax-table'.")
                (progn (set-match-data value) t))
           (ruby-match-expression-expansion limit)))))
 
+;;; Flymake support
+(defcustom ruby-flymake-command '("ruby" "-w" "-c")
+  "External tool used to check Ruby source code.
+This is a non empty list of strings, the checker tool possibly
+followed by required arguments.  Once launched it will receive
+the Ruby source to be checked as its standard input."
+  :group 'ruby
+  :type '(repeat string))
+
+(defvar-local ruby--flymake-proc nil)
+
+(defun ruby-flymake (report-fn &rest _args)
+  "Ruby backend for Flymake.  Launches
+`ruby-flymake-command' (which see) and passes to its standard
+input the contents of the current buffer. The output of this
+command is analysed for error and warning messages."
+  (unless (executable-find (car ruby-flymake-command))
+    (error "Cannot find a suitable checker"))
+
+  (when (process-live-p ruby--flymake-proc)
+    (kill-process ruby--flymake-proc))
+
+  (let ((source (current-buffer)))
+    (save-restriction
+      (widen)
+      (setq
+       ruby--flymake-proc
+       (make-process
+        :name "ruby-flymake" :noquery t :connection-type 'pipe
+        :buffer (generate-new-buffer " *ruby-flymake*")
+        :command ruby-flymake-command
+        :sentinel
+        (lambda (proc _event)
+          (when (eq 'exit (process-status proc))
+            (unwind-protect
+                (if (with-current-buffer source (eq proc ruby--flymake-proc))
+                    (with-current-buffer (process-buffer proc)
+                      (goto-char (point-min))
+                      (cl-loop
+                       while (search-forward-regexp
+                              "^\\(?:.*.rb\\|-\\):\\([0-9]+\\): \\(.*\\)$"
+                              nil t)
+                       for msg = (match-string 2)
+                       for (beg . end) = (flymake-diag-region
+                                          source
+                                          (string-to-number (match-string 1)))
+                       for type = (if (string-match "^warning" msg)
+                                      :warning
+                                    :error)
+                       collect (flymake-make-diagnostic source
+                                                        beg
+                                                        end
+                                                        type
+                                                        msg)
+                       into diags
+                       finally (funcall report-fn diags)))
+                  (flymake-log :debug "Canceling obsolete check %s"
+                               proc))
+              (kill-buffer (process-buffer proc)))))))
+      (process-send-region ruby--flymake-proc (point-min) (point-max))
+      (process-send-eof ruby--flymake-proc))))
+
 ;;;###autoload
 (define-derived-mode ruby-mode prog-mode "Ruby"
   "Major mode for editing Ruby code."
@@ -2265,6 +2327,7 @@ See `font-lock-syntax-table'.")
 
   (add-hook 'after-save-hook 'ruby-mode-set-encoding nil 'local)
   (add-hook 'electric-indent-functions 'ruby--electric-indent-p nil 'local)
+  (add-hook 'flymake-diagnostic-functions 'ruby-flymake nil 'local)
 
   (setq-local font-lock-defaults '((ruby-font-lock-keywords) nil nil))
   (setq-local font-lock-keywords ruby-font-lock-keywords)
diff --git a/lisp/progmodes/xref.el b/lisp/progmodes/xref.el
index 3dbf65ef6f5..db025d40aa3 100644
--- a/lisp/progmodes/xref.el
+++ b/lisp/progmodes/xref.el
@@ -448,43 +448,74 @@ If SELECT is non-nil, select the target window."
        (when xref-w
          (set-window-dedicated-p xref-w xref-w-dedicated)))))
 
-(defun xref--show-pos-in-buf (pos buf select)
-  (let ((xref-buf (current-buffer))
-        win)
+(defvar-local xref--original-window-intent nil
+  "Original window-switching intent before xref buffer creation.")
+
+(defvar-local xref--original-window nil
+  "The original window this xref buffer was created from.")
+
+(defun xref--show-pos-in-buf (pos buf)
+  "Goto and display position POS of buffer BUF in a window.
+Honor `xref--original-window-intent', run `xref-after-jump-hook'
+and finally return the window."
+  (let* ((xref-buf (current-buffer))
+         (pop-up-frames
+          (or (eq xref--original-window-intent 'frame)
+              pop-up-frames))
+         (action
+          (cond ((memq
+                  xref--original-window-intent
+                  '(window frame))
+                 t)
+                ((and
+                  (window-live-p xref--original-window)
+                  (or (not (window-dedicated-p xref--original-window))
+                      (eq (window-buffer xref--original-window) buf)))
+                 `(,(lambda (buf _alist)
+                      (set-window-buffer xref--original-window buf)
+                      xref--original-window))))))
     (with-selected-window
-        (xref--with-dedicated-window
-         (display-buffer buf))
+        (with-selected-window
+            ;; Just before `display-buffer', place ourselves in the
+            ;; original window to suggest preserving it. Of course, if
+            ;; user has deleted the original window, all bets are off,
+            ;; just use the selected one.
+            (or (and (window-live-p xref--original-window)
+                     xref--original-window)
+                (selected-window))
+          (display-buffer buf action))
       (xref--goto-char pos)
       (run-hooks 'xref-after-jump-hook)
       (let ((buf (current-buffer)))
-        (setq win (selected-window))
         (with-current-buffer xref-buf
-          (setq-local other-window-scroll-buffer buf))))
-    (when select
-      (select-window win))))
+          (setq-local other-window-scroll-buffer buf)))
+      (selected-window))))
 
 (defun xref--show-location (location &optional select)
+  "Help `xref-show-xref' and `xref-goto-xref' do their job.
+Go to LOCATION and if SELECT is non-nil select its window.  If
+SELECT is `quit', also quit the *xref* window."
   (condition-case err
       (let* ((marker (xref-location-marker location))
-             (buf (marker-buffer marker)))
-        (xref--show-pos-in-buf marker buf select))
+             (buf (marker-buffer marker))
+             (xref-buffer (current-buffer)))
+        (cond (select
+               (if (eq select 'quit) (quit-window nil nil))
+               (with-current-buffer xref-buffer
+                 (select-window (xref--show-pos-in-buf marker buf))))
+              (t
+               (save-selected-window
+                 (xref--with-dedicated-window
+                  (xref--show-pos-in-buf marker buf))))))
     (user-error (message (error-message-string err)))))
 
-(defvar-local xref--window nil
-  "The original window this xref buffer was created from.")
-
 (defun xref-show-location-at-point ()
   "Display the source of xref at point in the appropriate window, if any."
   (interactive)
   (let* ((xref (xref--item-at-point))
          (xref--current-item xref))
     (when xref
-      ;; Try to avoid the window the current xref buffer was
-      ;; originally created from.
-      (if (window-live-p xref--window)
-          (with-selected-window xref--window
-            (xref--show-location (xref-item-location xref)))
-        (xref--show-location (xref-item-location xref))))))
+      (xref--show-location (xref-item-location xref)))))
 
 (defun xref-next-line ()
   "Move to the next xref and display its source in the appropriate window."
@@ -503,12 +534,19 @@ If SELECT is non-nil, select the target window."
     (back-to-indentation)
     (get-text-property (point) 'xref-item)))
 
-(defun xref-goto-xref ()
-  "Jump to the xref on the current line and select its window."
+(defun xref-goto-xref (&optional quit)
+  "Jump to the xref on the current line and select its window.
+Non-interactively, non-nil QUIT means to first quit the *xref*
+buffer."
   (interactive)
   (let ((xref (or (xref--item-at-point)
                   (user-error "No reference at point"))))
-    (xref--show-location (xref-item-location xref) t)))
+    (xref--show-location (xref-item-location xref) (if quit 'quit t))))
+
+(defun xref-quit-and-goto-xref ()
+  "Quit *xref* buffer, then jump to xref on current line."
+  (interactive)
+  (xref-goto-xref t))
 
 (defun xref-query-replace-in-results (from to)
   "Perform interactive replacement of FROM with TO in all displayed xrefs.
@@ -632,6 +670,7 @@ references displayed in the current *xref* buffer."
     (define-key map (kbd "p") #'xref-prev-line)
     (define-key map (kbd "r") #'xref-query-replace-in-results)
     (define-key map (kbd "RET") #'xref-goto-xref)
+    (define-key map (kbd "TAB")  #'xref-quit-and-goto-xref)
     (define-key map (kbd "C-o") #'xref-show-location-at-point)
     ;; suggested by Johan Claesson "to further reduce finger movement":
     (define-key map (kbd ".") #'xref-next-line)
@@ -726,7 +765,8 @@ Return an alist of the form ((FILENAME . (XREF ...)) ...)."
         (xref--xref-buffer-mode)
         (pop-to-buffer (current-buffer))
         (goto-char (point-min))
-        (setq xref--window (assoc-default 'window alist))
+        (setq xref--original-window (assoc-default 'window alist)
+              xref--original-window-intent (assoc-default 'display-action alist))
         (current-buffer)))))
 
 
@@ -753,7 +793,8 @@ Return an alist of the form ((FILENAME . (XREF ...)) ...)."
    (t
     (xref-push-marker-stack)
     (funcall xref-show-xrefs-function xrefs
-             `((window . ,(selected-window)))))))
+             `((window . ,(selected-window))
+               (display-action . ,display-action))))))
 
 (defun xref--prompt-p (command)
   (or (eq xref-prompt-for-identifier t)
diff --git a/lisp/simple.el b/lisp/simple.el
index 375a79e7662..e09ddd2e689 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -3492,10 +3492,11 @@ the use of a shell (with its need to quote arguments)."
         (save-match-data
           (if (string-match "[ \t]*&[ \t]*\\'" command)
               ;; Command ending with ampersand means asynchronous.
-              (let ((buffer (get-buffer-create
-                             (or output-buffer "*Async Shell Command*")))
-                    (directory default-directory)
-                    proc)
+              (let* ((buffer (get-buffer-create
+                              (or output-buffer "*Async Shell Command*")))
+                     (bname (buffer-name buffer))
+                     (directory default-directory)
+                     proc)
                 ;; Remove the ampersand.
                 (setq command (substring command 0 (match-beginning 0)))
                 ;; Ask the user what to do with already running process.
@@ -3510,30 +3511,24 @@ the use of a shell (with its need to quote arguments)."
                    ((eq async-shell-command-buffer 'confirm-new-buffer)
                     ;; If will create a new buffer, query first.
                     (if (yes-or-no-p "A command is running in the default buffer.  Use a new buffer? ")
-                        (setq buffer (generate-new-buffer
-                                      (or (and (bufferp output-buffer) (buffer-name output-buffer))
-                                          output-buffer "*Async Shell Command*")))
+                        (setq buffer (generate-new-buffer bname))
                       (error "Shell command in progress")))
                    ((eq async-shell-command-buffer 'new-buffer)
                     ;; It will create a new buffer.
-                    (setq buffer (generate-new-buffer
-                                  (or (and (bufferp output-buffer) (buffer-name output-buffer))
-                                      output-buffer "*Async Shell Command*"))))
+                    (setq buffer (generate-new-buffer bname)))
                    ((eq async-shell-command-buffer 'confirm-rename-buffer)
                     ;; If will rename the buffer, query first.
                     (if (yes-or-no-p "A command is running in the default buffer.  Rename it? ")
                         (progn
                           (with-current-buffer buffer
                             (rename-uniquely))
-                          (setq buffer (get-buffer-create
-                                        (or output-buffer "*Async Shell Command*"))))
+                          (setq buffer (get-buffer-create bname)))
                       (error "Shell command in progress")))
                    ((eq async-shell-command-buffer 'rename-buffer)
                     ;; It will rename the buffer.
                     (with-current-buffer buffer
                       (rename-uniquely))
-                    (setq buffer (get-buffer-create
-                                  (or output-buffer "*Async Shell Command*"))))))
+                    (setq buffer (get-buffer-create bname)))))
                 (with-current-buffer buffer
                   (shell-command--save-pos-or-erase)
                   (setq default-directory directory)
@@ -3542,19 +3537,18 @@ the use of a shell (with its need to quote arguments)."
                   (setq mode-line-process '(":%s"))
                   (require 'shell) (shell-mode)
                   (set-process-sentinel proc 'shell-command-sentinel)
-                  ;; Use the comint filter for proper handling of carriage motion
-                  ;; (see `comint-inhibit-carriage-motion'),.
+                  ;; Use the comint filter for proper handling of
+                  ;; carriage motion (see comint-inhibit-carriage-motion).
                   (set-process-filter proc 'comint-output-filter)
                   (if async-shell-command-display-buffer
                       (display-buffer buffer '(nil (allow-no-window . t)))
                     (add-function :before (process-filter proc)
-                                  `(lambda (process string)
-                                     (when (and (= 0 (buffer-size (process-buffer process)))
-                                                (string= (buffer-name (process-buffer process))
-                                                    ,(or output-buffer "*Async Shell Command*")))
-                                       (display-buffer (process-buffer process))))
-                                  ))
-                  ))
+                                  (lambda (process _string)
+                                    (let ((buf (process-buffer process)))
+                                      (when (and (zerop (buffer-size buf))
+                                                 (string= (buffer-name buf)
+                                                          bname))
+                                        (display-buffer buf))))))))
             ;; Otherwise, command is executed synchronously.
             (shell-command-on-region (point) (point) command
                                      output-buffer nil error-buffer)))))))
diff --git a/lisp/textmodes/reftex-index.el b/lisp/textmodes/reftex-index.el
index 120370a149a..811d1477ada 100644
--- a/lisp/textmodes/reftex-index.el
+++ b/lisp/textmodes/reftex-index.el
@@ -474,7 +474,7 @@ With prefix 3, restrict index to region."
 
   (interactive)
 
-  ;; Ensure access to scanning info and rescan buffer if prefix are is '(4).
+  ;; Ensure access to scanning info and rescan buffer if prefix arg is '(4).
   (let ((current-prefix-arg current-prefix-arg))
     (reftex-ensure-index-support t)
     (reftex-access-scan-info current-prefix-arg))
diff --git a/lisp/textmodes/reftex-ref.el b/lisp/textmodes/reftex-ref.el
index f9f23201b43..8d69d8feda5 100644
--- a/lisp/textmodes/reftex-ref.el
+++ b/lisp/textmodes/reftex-ref.el
@@ -134,7 +134,7 @@ This function is controlled by the settings of reftex-insert-label-flags."
 
   (interactive)
 
-  ;; Ensure access to scanning info and rescan buffer if prefix are is '(4).
+  ;; Ensure access to scanning info and rescan buffer if prefix arg is '(4).
   (reftex-access-scan-info current-prefix-arg)
 
   ;; Find out what kind of environment this is and abort if necessary.
diff --git a/lisp/textmodes/reftex-toc.el b/lisp/textmodes/reftex-toc.el
index c7a598c920d..c694fafcd52 100644
--- a/lisp/textmodes/reftex-toc.el
+++ b/lisp/textmodes/reftex-toc.el
@@ -216,7 +216,7 @@ When called with a raw C-u prefix, rescan the document first."
   (or reftex-support-index
       (setq reftex-toc-include-index-entries nil))
 
-  ;; Ensure access to scanning info and rescan buffer if prefix are is '(4)
+  ;; Ensure access to scanning info and rescan buffer if prefix arg is '(4)
   (reftex-access-scan-info current-prefix-arg)
 
   (let* ((this-buf (current-buffer))
diff --git a/lisp/textmodes/tex-mode.el b/lisp/textmodes/tex-mode.el
index 3da6e4e1124..10ee10243ad 100644
--- a/lisp/textmodes/tex-mode.el
+++ b/lisp/textmodes/tex-mode.el
@@ -3512,7 +3512,8 @@ There might be text before point."
              (lambda (process _event)
                (when (eq (process-status process) 'exit)
                  (unwind-protect
-                     (when (eq process tex-chktex--process)
+                     (when (eq process
+                               (with-current-buffer source tex-chktex--process))
                        (with-current-buffer (process-buffer process)
                          (goto-char (point-min))
                          (cl-loop
diff --git a/lisp/vc/ediff.el b/lisp/vc/ediff.el
index d0f8e63dcb1..0adf51328e2 100644
--- a/lisp/vc/ediff.el
+++ b/lisp/vc/ediff.el
@@ -185,7 +185,9 @@
 
 ;;;###autoload
 (defun ediff-files (file-A file-B &optional startup-hooks)
-  "Run Ediff on a pair of files, FILE-A and FILE-B."
+  "Run Ediff on a pair of files, FILE-A and FILE-B.
+STARTUP-HOOKS is a list of functions that Emacs calls without
+arguments after setting up the Ediff buffers."
   (interactive
    (let ((dir-A (if ediff-use-last-dir
                     ediff-last-dir-A
@@ -221,7 +223,9 @@
 
 ;;;###autoload
 (defun ediff-files3 (file-A file-B file-C &optional startup-hooks)
-  "Run Ediff on three files, FILE-A, FILE-B, and FILE-C."
+  "Run Ediff on three files, FILE-A, FILE-B, and FILE-C.
+STARTUP-HOOKS is a list of functions that Emacs calls without
+arguments after setting up the Ediff buffers."
   (interactive
    (let ((dir-A (if ediff-use-last-dir
                     ediff-last-dir-A
@@ -419,7 +423,14 @@ If this file is a backup, `ediff' it with its original."
 
 ;;;###autoload
 (defun ediff-buffers (buffer-A buffer-B &optional startup-hooks job-name)
-  "Run Ediff on a pair of buffers, BUFFER-A and BUFFER-B."
+  "Run Ediff on a pair of buffers, BUFFER-A and BUFFER-B.
+STARTUP-HOOKS is a list of functions that Emacs calls without
+arguments after setting up the Ediff buffers.  JOB-NAME is a
+symbol describing the Ediff job type; it defaults to
+`ediff-buffers', but can also be one of
+`ediff-merge-files-with-ancestor', `ediff-last-dir-ancestor',
+`ediff-last-dir-C', `ediff-buffers3', `ediff-merge-buffers', or
+`ediff-merge-buffers-with-ancestor'."
   (interactive
    (let (bf)
      (list (setq bf (read-buffer "Buffer A to compare: "
@@ -441,7 +452,14 @@ If this file is a backup, `ediff' it with its original."
 ;;;###autoload
 (defun ediff-buffers3 (buffer-A buffer-B buffer-C
                                  &optional startup-hooks job-name)
-  "Run Ediff on three buffers, BUFFER-A, BUFFER-B, and BUFFER-C."
+  "Run Ediff on three buffers, BUFFER-A, BUFFER-B, and BUFFER-C.
+STARTUP-HOOKS is a list of functions that Emacs calls without
+arguments after setting up the Ediff buffers.  JOB-NAME is a
+symbol describing the Ediff job type; it defaults to
+`ediff-buffers3', but can also be one of
+`ediff-merge-files-with-ancestor', `ediff-last-dir-ancestor',
+`ediff-last-dir-C', `ediff-buffers', `ediff-merge-buffers', or
+`ediff-merge-buffers-with-ancestor'."
   (interactive
    (let (bf bff)
      (list (setq bf (read-buffer "Buffer A to compare: "
@@ -637,7 +655,8 @@ regular expression; only file names that match the regexp are considered."
 (defun ediff-merge-directories (dir1 dir2 regexp &optional merge-autostore-dir)
   "Run Ediff on a pair of directories, DIR1 and DIR2, merging files that have
 the same name in both.  The third argument, REGEXP, is nil or a regular
-expression; only file names that match the regexp are considered."
+expression; only file names that match the regexp are considered.
+MERGE-AUTOSTORE-DIR is the directory in which to store merged files."
   (interactive
    (let ((dir-A (ediff-get-default-directory-name))
          (default-regexp (eval ediff-default-filtering-regexp))
@@ -674,7 +693,8 @@ expression; only file names that match the regexp are considered."
 Ediff merges files that have identical names in DIR1, DIR2.  If a pair of files
 in DIR1 and DIR2 doesn't have an ancestor in ANCESTOR-DIR, Ediff will merge
 without ancestor.  The fourth argument, REGEXP, is nil or a regular expression;
-only file names that match the regexp are considered."
+only file names that match the regexp are considered.
+MERGE-AUTOSTORE-DIR is the directory in which to store merged files."
   (interactive
    (let ((dir-A (ediff-get-default-directory-name))
          (default-regexp (eval ediff-default-filtering-regexp))
@@ -710,7 +730,8 @@ only file names that match the regexp are considered."
                                              &optional merge-autostore-dir)
   "Run Ediff on a directory, DIR1, merging its files with their revisions.
 The second argument, REGEXP, is a regular expression that filters the file
-names.  Only the files that are under revision control are taken into account."
+names.  Only the files that are under revision control are taken into account.
+MERGE-AUTOSTORE-DIR is the directory in which to store merged files."
   (interactive
    (let ((dir-A (ediff-get-default-directory-name))
          (default-regexp (eval ediff-default-filtering-regexp))
@@ -740,7 +761,8 @@ names.  Only the files that are under revision control are taken into account."
                                                            merge-autostore-dir)
   "Run Ediff on a directory, DIR1, merging its files with their revisions and ancestors.
 The second argument, REGEXP, is a regular expression that filters the file
-names.  Only the files that are under revision control are taken into account."
+names.  Only the files that are under revision control are taken into account.
+MERGE-AUTOSTORE-DIR is the directory in which to store merged files."
   (interactive
    (let ((dir-A (ediff-get-default-directory-name))
          (default-regexp (eval ediff-default-filtering-regexp))
@@ -908,7 +930,9 @@ names.  Only the files that are under revision control are taken into account."
 With prefix argument, DUMB-MODE, or on a non-windowing display, works as
 follows:
 If WIND-A is nil, use selected window.
-If WIND-B is nil, use window next to WIND-A."
+If WIND-B is nil, use window next to WIND-A.
+STARTUP-HOOKS is a list of functions that Emacs calls without
+arguments after setting up the Ediff buffers."
   (interactive "P")
   (ediff-windows dumb-mode wind-A wind-B
                  startup-hooks 'ediff-windows-wordwise 'word-mode))
@@ -919,7 +943,9 @@ If WIND-B is nil, use window next to WIND-A."
 With prefix argument, DUMB-MODE, or on a non-windowing display, works as
 follows:
 If WIND-A is nil, use selected window.
-If WIND-B is nil, use window next to WIND-A."
+If WIND-B is nil, use window next to WIND-A.
+STARTUP-HOOKS is a list of functions that Emacs calls without
+arguments after setting up the Ediff buffers."
   (interactive "P")
   (ediff-windows dumb-mode wind-A wind-B
                  startup-hooks 'ediff-windows-linewise nil))
@@ -963,9 +989,12 @@ If WIND-B is nil, use window next to WIND-A."
 ;;;###autoload
 (defun ediff-regions-wordwise (buffer-A buffer-B &optional startup-hooks)
   "Run Ediff on a pair of regions in specified buffers.
+BUFFER-A and BUFFER-B are the buffers to be compared.
 Regions (i.e., point and mark) can be set in advance or marked interactively.
 This function is effective only for relatively small regions, up to 200
-lines.  For large regions, use `ediff-regions-linewise'."
+lines.  For large regions, use `ediff-regions-linewise'.
+STARTUP-HOOKS is a list of functions that Emacs calls without
+arguments after setting up the Ediff buffers."
   (interactive
    (let (bf)
      (list (setq bf (read-buffer "Region's A buffer: "
@@ -1003,10 +1032,13 @@ lines.  For large regions, use `ediff-regions-linewise'."
 ;;;###autoload
 (defun ediff-regions-linewise (buffer-A buffer-B &optional startup-hooks)
   "Run Ediff on a pair of regions in specified buffers.
+BUFFER-A and BUFFER-B are the buffers to be compared.
 Regions (i.e., point and mark) can be set in advance or marked interactively.
 Each region is enlarged to contain full lines.
 This function is effective for large regions, over 100-200
-lines.  For small regions, use `ediff-regions-wordwise'."
+lines.  For small regions, use `ediff-regions-wordwise'.
+STARTUP-HOOKS is a list of functions that Emacs calls without
+arguments after setting up the Ediff buffers."
   (interactive
    (let (bf)
      (list (setq bf (read-buffer "Region A's buffer: "
@@ -1127,7 +1159,11 @@ lines.  For small regions, use `ediff-regions-wordwise'."
                                  ;; MERGE-BUFFER-FILE is the file to be
                                  ;; associated with the merge buffer
                                  &optional startup-hooks merge-buffer-file)
-  "Merge two files without ancestor."
+  "Merge two files without ancestor.
+FILE-A and FILE-B are the names of the files to be merged.
+STARTUP-HOOKS is a list of functions that Emacs calls without
+arguments after setting up the Ediff buffers.  MERGE-BUFFER-FILE
+is the name of the file to be associated with the merge buffer.."
   (interactive
    (let ((dir-A (if ediff-use-last-dir
                     ediff-last-dir-A
@@ -1171,7 +1207,12 @@ lines.  For small regions, use `ediff-regions-wordwise'."
                                                ;; to be associated with the
                                                ;; merge buffer
                                                merge-buffer-file)
-  "Merge two files with ancestor."
+  "Merge two files with ancestor.
+FILE-A and FILE-B are the names of the files to be merged, and
+FILE-ANCESTOR is the name of the ancestor file.  STARTUP-HOOKS is
+a list of functions that Emacs calls without arguments after
+setting up the Ediff buffers.  MERGE-BUFFER-FILE is the name of
+the file to be associated with the merge buffer."
   (interactive
    (let ((dir-A (if ediff-use-last-dir
                     ediff-last-dir-A
@@ -1229,7 +1270,16 @@ lines.  For small regions, use `ediff-regions-wordwise'."
                                      ;; MERGE-BUFFER-FILE is the file to be
                                      ;; associated with the merge buffer
                                      startup-hooks job-name merge-buffer-file)
-  "Merge buffers without ancestor."
+  "Merge buffers without ancestor.
+BUFFER-A and BUFFER-B are the buffers to be merged.
+STARTUP-HOOKS is a list of functions that Emacs calls without
+arguments after setting up the Ediff buffers.  JOB-NAME is a
+symbol describing the Ediff job type; it defaults to
+`ediff-merge-buffers', but can also be one of
+`ediff-merge-files-with-ancestor', `ediff-last-dir-ancestor',
+`ediff-last-dir-C', `ediff-buffers', `ediff-buffers3', or
+`ediff-merge-buffers-with-ancestor'.  MERGE-BUFFER-FILE is the
+name of the file to be associated with the merge buffer."
   (interactive
    (let (bf)
      (list (setq bf (read-buffer "Buffer A to merge: "
@@ -1256,7 +1306,16 @@ lines.  For small regions, use `ediff-regions-wordwise'."
                                                    ;; file to be associated
                                                    ;; with the merge buffer
                                                    merge-buffer-file)
-  "Merge buffers with ancestor."
+  "Merge buffers with ancestor.
+BUFFER-A and BUFFER-B are the buffers to be merged, and
+BUFFER-ANCESTOR is their ancestor.  STARTUP-HOOKS is a list of
+functions that Emacs calls without arguments after setting up the
+Ediff buffers.  JOB-NAME is a symbol describing the Ediff job
+type; it defaults to `ediff-merge-buffers-with-ancestor', but can
+also be one of `ediff-merge-files-with-ancestor',
+`ediff-last-dir-ancestor', `ediff-last-dir-C', `ediff-buffers',
+`ediff-buffers3', or `ediff-merge-buffers'.  MERGE-BUFFER-FILE is
+the name of the file to be associated with the merge buffer."
   (interactive
    (let (bf bff)
      (list (setq bf (read-buffer "Buffer A to merge: "
@@ -1287,8 +1346,11 @@ lines.  For small regions, use `ediff-regions-wordwise'."
 (defun ediff-merge-revisions (&optional file startup-hooks merge-buffer-file)
   ;; MERGE-BUFFER-FILE is the file to be associated with the merge buffer
   "Run Ediff by merging two revisions of a file.
-The file is the optional FILE argument or the file visited by the current
-buffer."
+The file is the optional FILE argument or the file visited by the
+current buffer.  STARTUP-HOOKS is a list of functions that Emacs
+calls without arguments after setting up the Ediff buffers.
+MERGE-BUFFER-FILE is the name of the file to be associated with
+the merge buffer."
   (interactive)
   (if (stringp file) (find-file file))
   (let (rev1 rev2)
@@ -1319,8 +1381,11 @@ buffer."
                                             ;; buffer
                                             merge-buffer-file)
   "Run Ediff by merging two revisions of a file with a common ancestor.
-The file is the optional FILE argument or the file visited by the current
-buffer."
+The file is the optional FILE argument or the file visited by the
+current buffer.  STARTUP-HOOKS is a list of functions that Emacs
+calls without arguments after setting up the Ediff buffers.
+MERGE-BUFFER-FILE is the name of the file to be associated with
+the merge buffer."
   (interactive)
   (if (stringp file) (find-file file))
   (let (rev1 rev2 ancestor-rev)
@@ -1360,8 +1425,8 @@ buffer."
   "Query for a file name, and then run Ediff by patching that file.
 If optional PATCH-BUF is given, use the patch in that buffer
 and don't ask the user.
-If prefix argument, then: if even argument, assume that the patch is in a
-buffer. If odd -- assume it is in a file."
+If prefix argument ARG, then: if even argument, assume that the
+patch is in a buffer.  If odd -- assume it is in a file."
   (interactive "P")
   (let (source-dir source-file)
     (require 'ediff-ptch)
@@ -1394,7 +1459,7 @@ prompts for the buffer or a file, depending on the answer.
 With ARG=1, assumes the patch is in a file and prompts for the file.
 With ARG=2, assumes the patch is in a buffer and prompts for the buffer.
 PATCH-BUF is an optional argument, which specifies the buffer that contains the
-patch. If not given, the user is prompted according to the prefix argument."
+patch.  If not given, the user is prompted according to the prefix argument."
   (interactive "P")
   (require 'ediff-ptch)
   (setq patch-buf
@@ -1421,7 +1486,9 @@ patch. If not given, the user is prompted according to the prefix argument."
   "Run Ediff by comparing versions of a file.
 The file is an optional FILE argument or the file entered at the prompt.
 Default: the file visited by the current buffer.
-Uses `vc.el' or `rcs.el' depending on `ediff-version-control-package'."
+Uses `vc.el' or `rcs.el' depending on `ediff-version-control-package'.
+STARTUP-HOOKS is a list of functions that Emacs calls without
+arguments after setting up the Ediff buffers."
   ;; if buffer is non-nil, use that buffer instead of the current buffer
   (interactive "P")
   (if (not (stringp file))
@@ -1434,7 +1501,7 @@ Uses `vc.el' or `rcs.el' depending on `ediff-version-control-package'."
                                 'no-dirs)))
   (find-file file)
   (if (and (buffer-modified-p)
-           (y-or-n-p (format "Buffer %s is modified. Save buffer? "
+           (y-or-n-p (format "Buffer %s is modified.  Save buffer? "
                              (buffer-name))))
       (save-buffer (current-buffer)))
   (let (rev1 rev2)
@@ -1517,6 +1584,7 @@ With optional NODE, goes to that node."
 
 ;;;###autoload
 (defun ediff-files-command ()
+  "Call `ediff-files' with the next two command line arguments."
   (let ((file-a (nth 0 command-line-args-left))
         (file-b (nth 1 command-line-args-left)))
     (setq command-line-args-left (nthcdr 2 command-line-args-left))
@@ -1524,6 +1592,7 @@ With optional NODE, goes to that node."
 
 ;;;###autoload
 (defun ediff3-files-command ()
+  "Call `ediff3-files' with the next three command line arguments."
   (let ((file-a (nth 0 command-line-args-left))
         (file-b (nth 1 command-line-args-left))
         (file-c (nth 2 command-line-args-left)))
@@ -1532,6 +1601,7 @@ With optional NODE, goes to that node."
 
 ;;;###autoload
 (defun ediff-merge-command ()
+  "Call `ediff-merge-files' with the next two command line arguments."
   (let ((file-a (nth 0 command-line-args-left))
         (file-b (nth 1 command-line-args-left)))
     (setq command-line-args-left (nthcdr 2 command-line-args-left))
@@ -1539,6 +1609,7 @@ With optional NODE, goes to that node."
 
 ;;;###autoload
 (defun ediff-merge-with-ancestor-command ()
+  "Call `ediff-merge-files-with-ancestor' with the next three command line arguments."
   (let ((file-a (nth 0 command-line-args-left))
         (file-b (nth 1 command-line-args-left))
         (ancestor (nth 2 command-line-args-left)))
@@ -1547,6 +1618,7 @@ With optional NODE, goes to that node."
 
 ;;;###autoload
 (defun ediff-directories-command ()
+  "Call `ediff-directories' with the next three command line arguments."
   (let ((file-a (nth 0 command-line-args-left))
         (file-b (nth 1 command-line-args-left))
         (regexp (nth 2 command-line-args-left)))
@@ -1555,6 +1627,7 @@ With optional NODE, goes to that node."
 
 ;;;###autoload
 (defun ediff-directories3-command ()
+  "Call `ediff-directories3' with the next four command line arguments."
   (let ((file-a (nth 0 command-line-args-left))
         (file-b (nth 1 command-line-args-left))
         (file-c (nth 2 command-line-args-left))
@@ -1564,6 +1637,7 @@ With optional NODE, goes to that node."
 
 ;;;###autoload
 (defun ediff-merge-directories-command ()
+  "Call `ediff-merge-directories' with the next three command line arguments."
   (let ((file-a (nth 0 command-line-args-left))
         (file-b (nth 1 command-line-args-left))
         (regexp (nth 2 command-line-args-left)))
@@ -1572,6 +1646,7 @@ With optional NODE, goes to that node."
 
 ;;;###autoload
 (defun ediff-merge-directories-with-ancestor-command ()
+  "Call `ediff-merge-directories-with-ancestor' with the next four command line arguments."
   (let ((file-a (nth 0 command-line-args-left))
         (file-b (nth 1 command-line-args-left))
         (ancestor (nth 2 command-line-args-left))
diff --git a/lisp/window.el b/lisp/window.el
index f87294ceb15..8939e7d589b 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -6465,8 +6465,9 @@ If this is an integer, `split-window-sensibly' may split a window
 vertically only if it has at least this many lines.  If this is
 nil, `split-window-sensibly' is not allowed to split a window
 vertically.  If, however, a window is the only window on its
-frame, `split-window-sensibly' may split it vertically
-disregarding the value of this variable."
+frame, or all the other ones are dedicated,
+`split-window-sensibly' may split it vertically disregarding the
+value of this variable."
   :type '(choice (const nil) (integer :tag "lines"))
   :version "23.1"
   :group 'windows)
@@ -6573,15 +6574,27 @@ split."
              ;; Split window horizontally.
              (with-selected-window window
                (split-window-right)))
-        (and (eq window (frame-root-window (window-frame window)))
-             (not (window-minibuffer-p window))
-             ;; If WINDOW is the only window on its frame and is not the
-             ;; minibuffer window, try to split it vertically disregarding
-             ;; the value of `split-height-threshold'.
-             (let ((split-height-threshold 0))
-               (when (window-splittable-p window)
-                 (with-selected-window window
-                   (split-window-below))))))))
+        (and
+         ;; If WINDOW is the only usable window on its frame (it is
+         ;; the only one or, not being the only one, all the other
+         ;; ones are dedicated) and is not the minibuffer window, try
+         ;; to split it vertically disregarding the value of
+         ;; `split-height-threshold'.
+         (let ((frame (window-frame window)))
+           (or
+            (eq window (frame-root-window frame))
+            (catch 'done
+              (walk-window-tree (lambda (w)
+                                  (unless (or (eq w window)
+                                              (window-dedicated-p w))
+                                    (throw 'done nil)))
+                                frame)
+              t)))
+         (not (window-minibuffer-p window))
+         (let ((split-height-threshold 0))
+           (when (window-splittable-p window)
+             (with-selected-window window
+               (split-window-below))))))))
 
 (defun window--try-to-split-window (window &optional alist)
   "Try to split WINDOW.