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

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

[Pankaj Jangid]

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

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

[Andrii Kolomoiets]

Hello Pankaj,

> 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.

> 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".

Do you use python shipped with MacOS?

Mentioned section of the etc/PROBLEMS file has explanation:

This happens when python uses a libedit based readline module, which
is the default on macOS.

and link to bug#25753: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=25753

I'm using python installed via homebrew and native completions works fine.

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

[Pankaj Jangid]

>> 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.
>
> Do you use python shipped with MacOS?
>
> Mentioned section of the etc/PROBLEMS file has explanation:
>
> This happens when python uses a libedit based readline module, which
> is the default on macOS.
>
> and link to bug#25753: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=25753
>
> I'm using python installed via homebrew and native completions works fine.

Yes. With homebrew version it is working fine. And since this is
duplicate of 25753, I'll close this.

I was wondering why the python shell is working fine in the native
terminal. Are they not using readline?

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

[Pankaj Jangid]

Duplicate of 25753
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=25753

Closing. Works fine with homebrew's version of Python.

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

[Andrii Kolomoiets]

Pankaj Jangid <p4j@j4d.net> writes:

>>> 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.

>> This happens when python uses a libedit based readline module, which
>> is the default on macOS.

> Yes. With homebrew version it is working fine. And since this is
> duplicate of 25753, I'll close this.
>
> I was wondering why the python shell is working fine in the native
> terminal. Are they not using readline?

Different version of readline is used.

This code is used to check readline version:
import readline; print(readline.__doc__)

Under homebrew python it says "Importing this module enables command
line editing using GNU readline.".

Under python shipped with macos it says "Importing this module enables
command line editing using libedit readline."

Commit b33808ce77ef15c1f233790a2c93d9db4cc588ab disable native
completions when libedit readline is detected.

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

[Pankaj Jangid]

Andrii Kolomoiets <andreyk.mad@gmail.com> writes:
> Different version of readline is used.
>
> This code is used to check readline version:
> import readline; print(readline.__doc__)
>
> Under homebrew python it says "Importing this module enables command
> line editing using GNU readline.".
>
> Under python shipped with macos it says "Importing this module enables
> command line editing using libedit readline."
>
> Commit b33808ce77ef15c1f233790a2c93d9db4cc588ab disable native
> completions when libedit readline is detected.

Thanks for clarification. I appreciate it.

Regards,
-- 
Pankaj Jangid