bug#31760: 26.1; ruby-mode enables flymake-rubocop by default if the rubocop executable exists

[Petko Bordjukov]

Emacs 26.1 enables flymake-rubocop by default if the rubocop executable
is present in the system. Since most if not all of the warnings that
Rubocop generates are not raised by Ruby I consider them not adopted by
the Ruby community by default. Based on that, I propose that either
using Rubocop by default is turned off, or at least a more inteligent
per-project Rubocop detection scheme is implemented.

Steps to reproduce:

1. Have Ruby and the Rubocop gem installed.
2. Edit a file in ruby-mode
3. Enable flymake-mode
4. See flymake wranings from Rubocop

In GNU Emacs 26.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.30)
 of 2018-05-29 built on juergen
Windowing system distributor 'The X.Org Foundation', version 11.0.12000000
System Description:     Arch Linux

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS NOTIFY
ACL GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS
GTK3 X11 MODULES THREADS LIBSYSTEMD LCMS2

Important settings:
  value of $LC_MONETARY: bg_BG.UTF-8
  value of $LC_NUMERIC: bg_BG.UTF-8
  value of $LC_TIME: bg_BG.UTF-8
  value of $LANG: en_GB.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Ruby

Minor modes in effect:
  rspec-verifiable-mode: t
  robe-mode: t
  subword-mode: t
  yard-mode: t
  autopair-mode: t
  diff-hl-mode: t
  hl-line-mode: t
  rainbow-delimiters-mode: t
  yas-global-mode: t
  yas-minor-mode: t
  whitespace-mode: t
  flymake-mode: t
  ruby-block-mode: t
  global-auto-complete-mode: t
  auto-complete-mode: t
  projectile-rails-global-mode: t
  projectile-rails-mode: t
  inf-ruby-minor-mode: t
  global-rbenv-mode: t
  global-magit-file-mode: t
  magit-file-mode: t
  diff-auto-refine-mode: t
  magit-auto-revert-mode: t
  auto-revert-mode: t
  global-git-commit-mode: t
  async-bytecomp-package-mode: t
  shell-dirtrack-mode: t
  ido-ubiquitous-mode: t
  ido-vertical-mode: t
  ido-everywhere: t
  fic-mode: t
  erc-list-mode: t
  erc-menu-mode: t
  erc-autojoin-mode: t
  erc-ring-mode: t
  erc-networks-mode: t
  erc-pcomplete-mode: t
  erc-netsplit-mode: t
  erc-track-mode: t
  erc-match-mode: t
  erc-hl-nicks-mode: t
  erc-button-mode: t
  erc-fill-mode: t
  erc-stamp-mode: t
  erc-irccontrols-mode: t
  erc-noncommands-mode: t
  erc-move-to-prompt-mode: t
  erc-readonly-mode: t
  delete-selection-mode: t
  show-paren-mode: t
  cl-old-struct-compat-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
/home/ignisf/.emacs.d/elpa/flim-20180328.1624/hex-util hides 
/usr/share/emacs/26.1/lisp/hex-util
/home/ignisf/.emacs.d/elpa/flim-20180328.1624/md4 hides 
/usr/share/emacs/26.1/lisp/md4
/home/ignisf/.emacs.d/elpa/flim-20180328.1624/ntlm hides 
/usr/share/emacs/26.1/lisp/net/ntlm
/home/ignisf/.emacs.d/elpa/flim-20180328.1624/sasl-digest hides 
/usr/share/emacs/26.1/lisp/net/sasl-digest
/home/ignisf/.emacs.d/elpa/flim-20180328.1624/sasl-cram hides 
/usr/share/emacs/26.1/lisp/net/sasl-cram
/home/ignisf/.emacs.d/elpa/flim-20180328.1624/hmac-md5 hides 
/usr/share/emacs/26.1/lisp/net/hmac-md5
/home/ignisf/.emacs.d/elpa/flim-20180328.1624/hmac-def hides 
/usr/share/emacs/26.1/lisp/net/hmac-def
/home/ignisf/.emacs.d/elpa/flim-20180328.1624/sasl hides 
/usr/share/emacs/26.1/lisp/net/sasl
/home/ignisf/.emacs.d/elpa/flim-20180328.1624/sasl-ntlm hides 
/usr/share/emacs/26.1/lisp/net/sasl-ntlm

Features:
(shadow sort mail-extr emacsbug sendmail smex vc-git rspec-mode ac-robe
robe etags xref project cap-words superword subword yard-mode autopair
diff-hl vc-dir ewoc vc vc-dispatcher hl-line rainbow-delimiters
elec-pair image-file yasnippet windmove whitespace flymake-rust
flymake-easy flymake-proc flymake warnings rvm ruby-block
auto-complete-config auto-complete popup projectile-rails rake f
inflections inf-ruby ruby-mode-expansions ruby-mode smie projectile grep
compile ibuf-ext ibuffer ibuffer-loaddefs cl rbenv multiple-cursors
mc-hide-unmatched-lines-mode mc-separate-operations
rectangular-region-mode mc-mark-pop mc-mark-more mc-cycle-cursors
mc-edit-lines multiple-cursors-core rect web-mode-expansions web-mode
disp-table magit-obsolete magit-blame magit-stash magit-bisect
magit-remote magit-commit magit-sequence magit-notes magit-worktree
magit-tag magit-merge magit-branch magit-reset magit-collab ghub
url-http tls gnutls url-gw nsm url-auth url url-proxy url-privacy
url-expand url-methods url-history url-cookie url-domsuf url-util
mailcap let-alist json map magit-files magit-refs magit-status magit
magit-repos magit-apply magit-wip magit-log magit-diff smerge-mode
diff-mode magit-core magit-autorevert autorevert filenotify
magit-process magit-margin magit-mode git-commit magit-git magit-section
magit-utils crm subr-x magit-popup log-edit message rmc puny rfc822 mml
mml-sec epa derived epg gnus-util rmail rmail-loaddefs mm-decode
mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 mm-util
ietf-drums mail-prsvr mailabbrev mail-utils gmm-utils mailheader
pcvs-util add-log with-editor cl-extra help-mode async-bytecomp async
shell server dash ido-completing-read+ memoize s cus-edit cus-start
cus-load minibuf-eldef ido-vertical-mode ido fic-mode edmacro kmacro
expand-region text-mode-expansions er-basic-expansions
expand-region-core advice expand-region-custom erc-list erc-menu
erc-join erc-ring erc-networks erc-pcomplete pcomplete comint ansi-color
ring erc-netsplit erc-image image-dired image-mode dired dired-loaddefs
url-queue browse-url erc-track erc-match erc-hl-nicks color erc-button
erc-fill erc-stamp wid-edit easy-mmode erc-goodies erc erc-backend
erc-compat format-spec thingatpt pp delsel paren finder-inf
commander-autoloads eimp-autoloads flymake-yaml-autoloads
logito-autoloads mark-multiple-autoloads rx shift-text-autoloads
smooth-scroll-autoloads vline-autoloads info package easymenu epg-config
url-handlers url-parse auth-source cl-seq eieio eieio-core cl-macs
eieio-loaddefs password-cache url-vars seq byte-opt gv bytecomp
byte-compile cconv cl-loaddefs cl-lib time-date mule-util tooltip eldoc
electric uniquify ediff-hook vc-hooks lisp-float-type mwheel term/x-win
x-win term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow isearch timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote dbusbind inotify lcms2 dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty
make-network-process emacs)

Memory information:
((conses 16 407364 38576)
 (symbols 48 44516 2)
 (miscs 40 500 592)
 (strings 32 122750 4102)
 (string-bytes 1 3488793)
 (vectors 16 47453)
 (vector-slots 8 881674 22598)
 (floats 8 302 453)
 (intervals 56 677 27)
 (buffers 992 17))