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

10 files changed, 397 insertions, 52 deletions

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)