bug#54860: 28.1; Problem with run-python

[Robert Thorpe]

I recently upgraded to Emacs 28.1 on Microsoft Windows.  I'm having
problems with Inferior Python mode.  On Emacs 27.2 that mode works.
However, it doesn't work on Emacs 28.1, not even from emacs -Q.

Reproduction is easy, from emacs -Q do "M-x run-python" on a Windows 10
machine.

The variable exec-path contains the path to the python interpreter
("C:/Program Files/Python39/").  Emacs is correctly picking up the
components of exec-path from my PATH environmental variable.

However, run-python gives the error:
"Python was not found; run with arguments to install from the Microsoft
Store, or disable this shortcut from Setting > Manage App Execution
Aliases.

Process Python exited abnormally with code 49"

I also get a warnings buffer telling me that the python prompts cannot
be detected.

In the Microsoft "Manage App Execution Aliases" I have turned off all
python related aliases.

The python shell works fine from a Windows cmd shell.

(I am sending this from Emacs 27.2 on Arch but I have copied over the
debug text blocks below from the machine with the problem).

BR,
Robert Thorpe



In GNU Emacs 28.1 (build 52, x86_64-w64-mingw32)
 of 2022-04-04 built on AVALON
Repository revision: 5a223c7f2ef4c31abbd46367b6ea83cd19d30aa7
Repository branch: heads/emacs-28.1
Windowing system distributor 'Microsoft Corp.', version 10.0.19042
System Description: Microsoft Windows 10 Enterprise (v10.0.2009.19042.1586)

Configured using:
 'configure --without-dbus --with-native-compilation
 --without-compress-install CFLAGS=-O2'

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG JSON LCMS2 LIBXML2 MODULES NATIVE_COMP
NOTIFY W32NOTIFY PDUMPER PNG RSVG SOUND THREADS TIFF TOOLKIT_SCROLL_BARS
XPM ZLIB

(NATIVE_COMP present but libgccjit not available)

Important settings:
  value of $LANG: ENI
  locale-coding-system: cp1252

Major mode: Inferior Python

Minor modes in effect:
  compilation-shell-minor-mode: t
  shell-dirtrack-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-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

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
rfc822 mml mml-sec epa derived epg rfc6068 epg-config gnus-util rmail
rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils compile text-property-search warnings
python tramp-sh tramp tramp-loaddefs trampver tramp-integration files-x
tramp-compat shell pcomplete parse-time iso8601 time-date format-spec
auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs
password-cache json subr-x map seq byte-opt gv bytecomp byte-compile
cconv comint ring cl-loaddefs cl-lib ansi-color iso-transl tooltip eldoc
paren electric uniquify ediff-hook vc-hooks lisp-float-type elisp-mode
mwheel dos-w32 ls-lisp disp-table term/w32-win w32-win w32-vars
term/common-win tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode lisp-mode prog-mode register
page tab-bar menu-bar rfn-eshadow isearch easymenu timer select
scroll-bar mouse jit-lock font-lock syntax 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 emoji-zwj charscript charprop case-table epa-hook
jka-cmpr-hook help simple abbrev obarray cl-preloaded nadvice button
loaddefs faces cus-face macroexp files window text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote threads w32notify w32 lcms2 multi-tty
make-network-process native-compile emacs)

Memory information:
((conses 16 74179 7585)
 (symbols 48 8907 1)
 (strings 32 27995 1889)
 (string-bytes 1 962898)
 (vectors 16 17454)
 (vector-slots 8 249009 10766)
 (floats 8 43 224)
 (intervals 56 253 0)
 (buffers 992 14))