GNU bug report logs - #21831
24.5 on Windows; start-process modifies its PROGRAM argument

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Cornelius Mika <cornelius.mika <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: 24.5 on Windows; start-process modifies its PROGRAM argument
Date: Wed, 4 Nov 2015 21:31:55 +0100

[Message part 1 (text/plain, inline)]

start-process normalizes the given PROGRAM path by destructively modifying
its contents.
This is problematic if the path variable is reused later on.

Minimal repro:
(let ((path "c:/Windows/System32/clip.exe"))
  (start-process "" nil path)
  path) ; => "c:\\Windows\\System32\\clip.exe"

In GNU Emacs 24.5.1 (i686-pc-mingw32)
 of 2015-04-11 on LEG570
Windowing system distributor `Microsoft Corp.', version 6.3.9600
Configured using:
 `configure --prefix=/c/usr --host=i686-pc-mingw32'

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  value of $LANG: DEU
  locale-coding-system: cp1252

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  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
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  transient-mark-mode: t

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[Message part 2 (text/html, inline)]

Message #10 received at 21831-done <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Cornelius Mika <cornelius.mika <at> gmail.com>
Cc: 21831-done <at> debbugs.gnu.org
Subject: Re: bug#21831: 24.5 on Windows;
 start-process modifies its PROGRAM argument
Date: Wed, 04 Nov 2015 23:01:48 +0200

> From: Cornelius Mika <cornelius.mika <at> gmail.com>
> Date: Wed, 4 Nov 2015 21:31:55 +0100
> 
> start-process normalizes the given PROGRAM path by destructively modifying its
> contents.
> This is problematic if the path variable is reused later on.
> 
> Minimal repro:
> (let ((path "c:/Windows/System32/clip.exe"))
> (start-process "" nil path)
> path) ; => "c:\\Windows\\System32\\clip.exe"
> 
> In GNU Emacs 24.5.1 (i686-pc-mingw32)
> of 2015-04-11 on LEG570
> Windowing system distributor `Microsoft Corp.', version 6.3.9600
> Configured using:
> `configure --prefix=/c/usr --host=i686-pc-mingw32'

Thanks.

I can reproduce this in Emacs 24.5, but not in the current development
sources.  So this problem was already fixed as part of the development
since then, and I see the code which was added to avoid this.

So I'm marking this bug done.

Message #13 received at 21831 <at> debbugs.gnu.org (full text, mbox):

From: Nicolas Richard <youngfrog <at> members.fsf.org>
To: 21831 <at> debbugs.gnu.org
Cc: cornelius.mika <at> gmail.com, eliz <at> gnu.org
Subject: Re: bug#21831: 24.5 on Windows;
 start-process modifies its PROGRAM argument
Date: Thu, 05 Nov 2015 09:42:54 +0100

Eli Zaretskii <eliz <at> gnu.org> writes:

>> From: Cornelius Mika <cornelius.mika <at> gmail.com>
>> Minimal repro:
>> (let ((path "c:/Windows/System32/clip.exe"))
>> (start-process "" nil path)
>> path) ; => "c:\\Windows\\System32\\clip.exe"

> I can reproduce this in Emacs 24.5, but not in the current development
> sources.  So this problem was already fixed as part of the development
> since then, and I see the code which was added to avoid this.

Thanks for checking.
Did you see a test associated to this fix ?

perhaps something like :

(ert-deftest start-process-should-not-modify-arguments ()
  "`start-process' must not modify its arguments in-place."
  ;; See bug#21831.
  (let* ((path (pcase system-type
                 ('windows-nt  "c:/Windows/System32/clip.exe")
                 ('ms-dos "c:/command.com")
                 (_ "/bin//sh")))
         (samepath (copy-sequence path)))
    (start-process "" nil path)
    (should (equal path samepath))))

to be included in test/automated/process-tests.el

I'm not sure what a good value of `path' might be.

-- 
Nico.

Message #16 received at 21831 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Nicolas Richard <youngfrog <at> members.fsf.org>
Cc: cornelius.mika <at> gmail.com, 21831 <at> debbugs.gnu.org
Subject: Re: bug#21831: 24.5 on Windows;
 start-process modifies its PROGRAM argument
Date: Thu, 05 Nov 2015 20:14:02 +0200

> From: Nicolas Richard <youngfrog <at> members.fsf.org>
> Cc: eliz <at> gnu.org,  cornelius.mika <at> gmail.com
> Date: Thu, 05 Nov 2015 09:42:54 +0100
> 
> Did you see a test associated to this fix ?
> 
> perhaps something like :

Thanks, I pushed a variant of your suggested test.

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