bug#38734: 27.0.60; C-c C-p Warning - 'python-shell-interpreter' doesn't seem to support readline ...

[Pankaj Jangid <p4j@j4d.net>]

The below description is for normal mode without any CLI options. But
emacs -Q also produces same warnings. The only difference is that emacs
-Q uses Python2 instead of Python3. I have configured Python3 in this
directory (venv).

In python-mode, when I pressed C-c C-p to launch Python shell it
produced below warning. I am on MacOS Catalina 10.15.2. On MacOS
terminal, the python-shell opens without any warning.

In buffer *Warning*

Warning (python): Your ‘python-shell-interpreter’ doesn’t seem to support readline, yet ‘python-shell-completion-native-enable’ was t and "python" is not part of the ‘python-shell-completion-native-disabled-interpreters’ list.  Native completions have been disabled locally. 

In buffer *Python*

Python 3.7.3 (default, Nov 15 2019, 04:04:52) 
[Clang 11.0.0 (clang-1100.0.33.16)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import codecs, os;__pyfile = codecs.open('''/var/folders/lf/kn5fshdx4md8xcmv02rntfzr0000gn/T/py62bj9y''', encoding='''utf-8''');__code = __pyfile.read().encode('''utf-8''');__pyfile.close();os.remove('''/var/folders/lf/kn5fshdx4md8xcmv02rntfzr0000gn/T/py62bj9y''');exec(compile(__code, '''/var/folders/lf/kn5fshdx4md8xcmv02rntfzr0000gn/T/py62bj9y''', 'exec'));
python.el: native completion setup failed, <class 'Exception'>: libedit based readline is known not to work,
      see etc/PROBLEMS under "In Inferior Python mode, input is echoed".
>>> 


In GNU Emacs 27.0.60 (build 1, x86_64-apple-darwin19.2.0, NS appkit-1894.20 Version 10.15.2 (Build 19C57))
 of 2019-12-24 built on Pankajs-MacBook-Pro.local
Repository revision: 6184aa003f44363e42762031ca368502021f9e7a
Repository branch: emacs-27
Windowing system distributor 'Apple', version 10.3.1894
System Description:  Mac OS X 10.15.2

Recent messages:
Sole completion
C-x C-k C-g is undefined
Shell native completion is disabled, using fallback
Mark set
Shell native completion is disabled, using fallback
Mark set
next-line: End of buffer
Mark set [3 times]
next-line: End of buffer
Mark set [2 times]
next-line: End of buffer [2 times]
Configured using:
 'configure LDFLAGS=-L/usr/local/opt/ruby/lib
 CPPFLAGS=-I/usr/local/opt/ruby/include
 PKG_CONFIG_PATH=:/usr/local/opt/sqlite/lib/pkgconfig:/usr/local/opt/libxml2/lib/pkgconfig:/usr/local/opt/openssl/lib/pkgconfig:/usr/local/opt/libffi/lib/pkgconfig:/usr/local/opt/ruby/lib/pkgconfig
 'HARFBUZZ_CFLAGS=-I/usr/local/Cellar/harfbuzz/2.6.4/include/harfbuzz
 -I/usr/local/Cellar/glib/2.62.2/include/glib-2.0
 -I/usr/local/Cellar/glib/2.62.2/lib/glib-2.0/include
 -I/usr/local/opt/gettext/include -I/usr/local/Cellar/pcre/8.43/include
 -I/usr/local/Cellar/graphite2/1.3.13/include'
 'HARFBUZZ_LIBS=-L/usr/local/Cellar/harfbuzz/2.6.4/lib -lharfbuzz''

Configured features:
RSVG DBUS GLIB NOTIFY KQUEUE ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS
NS MODULES THREADS JSON PDUMPER LCMS2 GMP

Important settings:
  value of $LANG: en_IN.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  shell-dirtrack-mode: t
  company-mode: t
  display-line-numbers-mode: t
  yas-minor-mode: t
  electric-pair-mode: t
  direnv-mode: t
  show-paren-mode: t
  which-key-mode: t
  flymake-mode: t
  display-time-mode: t
  global-hl-line-mode: t
  projectile-mode: t
  icomplete-mode: t
  recentf-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t
  hs-minor-mode: t

Load-path shadows:
None found.

Features:
(shadow bbdb-message vc-mtn vc-hg flyspell ispell emacsbug sendmail
two-column iso-transl vc-bzr vc-src vc-sccs vc-svn vc-cvs vc-rcs vc
vc-dispatcher eglot array filenotify jsonrpc ert ewoc python tramp-sh
tramp tramp-loaddefs trampver tramp-integration files-x tramp-compat
shell ls-lisp ido autoload checkdoc lisp-mnt gnus-kill shr-color vc-git
diff-mode sort gnus-cite smiley mail-extr gnus-async gnus-bcklg qp
gnus-ml disp-table gnus-topic nndraft nnmh utf-7 nnfolder bbdb-gnus
epa-file gnus-agent gnus-srvr gnus-score score-mode nnvirtual gnus-msg
gnus-art mm-uu mml2015 mm-view mml-smime smime dig nntp gnus-cache
gnus-sum shr svg xml dom gnus-group gnus-undo gnus-start gnus-cloud
nnimap nnmail mail-source utf7 netrc nnoo parse-time iso8601 gnus-spec
gnus-int gnus-range gnus-win gnus nnheader help-fns radix-tree cl-print
debug backtrace mm-archive message dired dired-loaddefs rfc822 mml
mml-sec epa derived gnus-util rmail rmail-loaddefs text-property-search
gmm-utils mailheader mm-decode mm-bodies mm-encode mail-utils gnutls
network-stream url-http mail-parse rfc2231 rfc2047 rfc2045 mm-util
ietf-drums mail-prsvr url-gw nsm rmc puny url-cache url-auth url
url-proxy url-privacy url-expand url-methods url-history url-cookie
url-domsuf url-util mailcap epg epg-config finder-inf cl-extra
company-oddmuse company-keywords company-etags etags fileloop generator
xref project company-gtags company-dabbrev-code company-dabbrev
company-files company-capf company-cmake company-xcode company-clang
company-semantic company-eclim company-template company-bbdb company
pcase display-line-numbers yasnippet help-mode elec-pair hideshow direnv
dash sanityinc-tomorrow-bright-theme color-theme-sanityinc-tomorrow
color paren which-key init server init-prog flymake-proc flymake
warnings init-edit init-keys init-looks time hl-line init-env
exec-path-from-shell init-melpa init-tools projectile grep compile
ibuf-ext ibuffer ibuffer-loaddefs ob-C cc-mode cc-fonts cc-guess
cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs ob-python
org ob ob-tangle ob-ref ob-lob ob-table ob-exp org-macro org-footnote
org-src ob-comint org-pcomplete pcomplete comint ansi-color ring
org-list org-faces org-entities time-date noutline outline easy-mmode
org-version ob-emacs-lisp ob-core ob-eval org-table ol org-keys
org-compat advice org-macs org-loaddefs find-func cal-menu calendar
cal-loaddefs bbdb-mua bbdb-com crm mailabbrev bbdb bbdb-site timezone
icomplete edmacro kmacro erc-auth erc-join erc-goodies erc erc-backend
erc-compat format-spec thingatpt pp erc-loaddefs recentf tree-widget
wid-edit rx info package easymenu browse-url url-handlers url-parse
auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs
password-cache json subr-x map url-vars seq byte-opt gv bytecomp
byte-compile cconv cl-loaddefs cl-lib early-init tooltip eldoc electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel term/ns-win ns-win
ucs-normalize mule-util term/common-win tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode
lisp-mode prog-mode register page tab-bar menu-bar rfn-eshadow isearch
timer select scroll-bar mouse jit-lock font-lock syntax facemenu
font-core term/tty-colors frame minibuffer 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
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 threads dbusbind kqueue
cocoa ns lcms2 multi-tty make-network-process emacs)

Memory information:
((conses 16 1411092 67127)
 (symbols 48 41626 6)
 (strings 32 251941 11869)
 (string-bytes 1 9850373)
 (vectors 16 75927)
 (vector-slots 8 1100725 98690)
 (floats 8 552 401)
 (intervals 56 146254 608)
 (buffers 1000 49))

-- 
Pankaj Jangid