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bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command
From: |
Noam Postavsky |
Subject: |
bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell |
Date: |
Wed, 10 Aug 2016 09:00:36 -0400 |
tag 19350 confirmed
severity 19350 minor
quit
> Looking at the code in subr.el, it is clear that Emacs mishandles
> %-signs when escaping for the Windows command interpreter.
[...]
>
> I deleted the lossage from the report, as there is no point in including
> it, this being a logic error in subr.el. In fact, the buggy code is dead
> on my machine (I run Linux) -- I happened to know about the problem on
> Windows.
Well, it would have been nice to mention which function you're talking
about, and give an example problematic string. I guess it's
shell-quote-argument:
Evaluating
(let ((process-environment (cl-list* "ca^=with-caret"
"ca=without-caret"
process-environment)))
(insert (shell-command-to-string
(format "echo %s %s %s"
"%ca%"
(shell-quote-argument "%ca%")
"%%CD:~,0%ca%%CD:~,0%"))))
gives
without-caret "with-caret" %ca%
On the other hand, this is such an obscure corner case, I'm don't know
if it's even worth fixing.
> A method of handling % that I believe to be fully
> robust is to follow (not precede) each series of % characters with
> %CD:~,0%. This is an expansion that always expands to the empty
> string. It will work provided that:
>
> * Command Extensions are enabled.
I'm not sure if Emacs can assume this.
>
> * It is not possible for cmd.exe to interpret an environment variable
> whose name is the empty string.
I found that adding "=emptyvar" to process-environment caused
"Spawning child process: exec format error", so I guess this
assumption is safe.
- bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell,
Noam Postavsky <=
- bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell, Eli Zaretskii, 2016/08/10
- bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell, Demi Obenour, 2016/08/11
- bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell, npostavs, 2016/08/11
- Message not available
- Message not available
- bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell, Demi Obenour, 2016/08/14
- bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell, npostavs, 2016/08/14
- bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell, Eli Zaretskii, 2016/08/15
- bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell, Demi Obenour, 2016/08/17
- bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell, Noam Postavsky, 2016/08/17
- bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell, Demi Obenour, 2016/08/18
- bug#19350: #19350 24.4; Incorrect quoting of %-signs for Windows command shell, Noam Postavsky, 2016/08/18