bug#71446: 30.0.50; em-extpipe-test-14 fails on MS-Windows

[Eli Zaretskii]

The failure is as follows:

  Test em-extpipe-test-14 backtrace:
    signal(ert-test-failed (((should (eshell-match-output regexp)) :form
    ert-fail(((should (eshell-match-output regexp)) :form (eshell-match-
    (if (unwind-protect (setq value-2 (apply fn-0 args-1)) (setq form-de
    (let (form-description-4) (if (unwind-protect (setq value-2 (apply f
    (let ((value-2 'ert-form-evaluation-aborted-3)) (let (form-descripti
    (let* ((fn-0 #'eshell-match-output) (args-1 (condition-case err (lis
    (let ((ert--infos (cons (cons "Command logs: " #'eshell-get-debug-lo
    eshell-match-command-output("tac *<c:/Users/EliZ/AppData/Local/Temp/
    (let ((input (replace-regexp-in-string "temp\\([^>]\\|\\'\\)" temp (
    (unwind-protect (let ((input (replace-regexp-in-string "temp\\([^>]\
    (let ((temp-buffer (generate-new-buffer " *tmp*" t))) (unwind-protec
    (progn (let ((temp-buffer (generate-new-buffer " *tmp*" t))) (unwind
    (unwind-protect (progn (let ((temp-buffer (generate-new-buffer " *tm
    (let* ((coding-system-for-write nil) (temp-file (identity (make-temp
    (save-current-buffer (set-buffer eshell-buffer) (let* ((fn-236 #'exe
    (unwind-protect (save-current-buffer (set-buffer eshell-buffer) (let
    (let ((eshell-buffer (eshell t))) (unwind-protect (save-current-buff
    (let ((process-environment (cons "HISTFILE" process-environment)) (e
    (progn (let ((process-environment (cons "HISTFILE" process-environme
    (unwind-protect (progn (let ((process-environment (cons "HISTFILE" p
    (let* ((coding-system-for-write nil) (temp-file (file-name-as-direct
    (save-current-buffer (let* ((coding-system-for-write nil) (temp-file
    (let ((input "tac *<temp")) (save-current-buffer (let* ((coding-syst
    (progn (let ((value-227 (gensym "ert-form-evaluation-aborted-"))) (l
    #f(lambda () [t] (progn (let ((value-227 ...)) (let (form-descriptio
    #f(compiled-function () #<bytecode -0x10ea5719bcc961a>)()
    handler-bind-1(#f(compiled-function () #<bytecode -0x10ea5719bcc961a
    ert--run-test-internal(#s(ert--test-execution-info :test #s(ert-test
    ert-run-test(#s(ert-test :name em-extpipe-test-14 :documentation nil
    ert-run-or-rerun-test(#s(ert--stats :selector ... :tests ... :test-m
    ert-run-tests((not (or (tag :unstable) (tag :nativecomp))) #f(compil
    ert-run-tests-batch((not (or (tag :unstable) (tag :nativecomp))))
    ert-run-tests-batch-and-exit((not (or (tag :unstable) (tag :nativeco
    eval((ert-run-tests-batch-and-exit '(not (or (tag :unstable) (tag :n
    command-line-1(("-L" ";." "-l" "ert" "--eval" "(setq treesit-extra-l
    command-line()
    normal-top-level()
  Test em-extpipe-test-14 condition:
      Command logs: command: "tac 
*<c:/Users/EliZ/AppData/Local/Temp/emacs-test-hYLZuB-em-extpipe"

                    ----------------------------------------
                    [process] started external process `cmdproxy.exe'

                    d\:/gnu/git/emacs/trunk/nt/cmdproxy.exe -c tac\ 
\<c\:/Users/EliZ/AppData/Local/Temp/emacs-test-hYLZuB-em-extpipe
                    ----------------------------------------
                    [process] received output from process `cmdproxy.exe'

                    tac: standard input: read error

                    ----------------------------------------
                    [process] sentinel for external process `cmdproxy.exe': 
"exited abnormally with code 1
                    "
                    ----------------------------------------
                    [process] finished external process `cmdproxy.exe'
      (ert-test-failed
       ((should (eshell-match-output regexp)) :form
        (eshell-match-output "baz\nbar") :value nil :explanation
        (mismatched-output
         (command
          "tac 
*<c:/Users/EliZ/AppData/Local/Temp/emacs-test-hYLZuB-em-extpipe\n")
         (output "tac: standard input: read error\n") (regexp "baz\nbar"))))
     FAILED   6/17  em-extpipe-test-14 (0.133600 sec) at 
lisp/eshell/em-extpipe-tests.el:180

AFAIU, the problem is that this invokes 'tac' with redirection, but
the redirected file name uses Unix-style forward slashes, which
doesn't work on Windows: the file name after "<" must use backslashes.

I tried to fix that, but the problem is that with-substitute-for-temp
is general, not specific to redirected file names, and OTOH
em-extpipe-test-14 doesn't get at the file name 'temp' until it's too
late.  But maybe I' missing something in the tangled web of nested
macros?

I also don't understand all those backslashes in

  d\:/gnu/git/emacs/trunk/nt/cmdproxy.exe -c tac\ 
\<c\:/Users/EliZ/AppData/Local/Temp/emacs-test-hYLZuB-em-extpipe

Are they real or just some artifact of printing the command?  If they
are real, and included in the command line, then perhaps my analysis
is incorrect and there are more fundamental problems here.

In GNU Emacs 30.0.50 (build 1367, i686-pc-mingw32) of 2024-06-09 built
 on ELIZ-PC
Windowing system distributor 'Microsoft Corp.', version 10.0.22631
System Description: Microsoft Windows 10 Enterprise (v10.0.2009.22631.3593)

Configured using:
 'configure -C --prefix=/d/usr --with-wide-int
 --without-native-compilation --enable-checking=yes,glyphs 'CFLAGS=-O0
 -gdwarf-4 -g3''

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG LCMS2 LIBXML2 MODULES NOTIFY W32NOTIFY
PDUMPER PNG RSVG SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS
TREE_SITTER WEBP XPM ZLIB

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

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  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
  minibuffer-regexp-mode: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
epg-config gnus-util text-property-search time-date subr-x mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
cl-loaddefs cl-lib sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils rmc iso-transl tooltip cconv 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 nadvice seq
simple cl-generic indonesian philippine 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 abbrev obarray oclosure cl-preloaded button
loaddefs theme-loaddefs faces cus-face macroexp files window
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget keymap hashtable-print-readable backquote threads
w32notify w32 lcms2 multi-tty move-toolbar make-network-process emacs)

Memory information:
((conses 16 45257 13060) (symbols 48 6519 0) (strings 16 16057 3095)
 (string-bytes 1 331106) (vectors 16 9308)
 (vector-slots 8 108624 10530) (floats 8 23 6) (intervals 40 297 92)
 (buffers 896 10))