GNU bug report logs - #63648
29.0.90; project.el: with switch-use-entire-map, switch-project errors on non-project commands

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Package: emacs;

Reported by: Spencer Baugh <sbaugh <at> janestreet.com>

Date: Mon, 22 May 2023 16:29:02 UTC

Severity: normal

Found in version 29.0.90

Done: Dmitry Gutov <dmitry <at> gutov.dev>

Bug is archived. No further changes may be made.

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Message #158 received at 63648 <at> debbugs.gnu.org (full text, mbox):

From: Juri Linkov <juri <at> linkov.net>
To: Spencer Baugh <sbaugh <at> janestreet.com>
Cc: Dmitry Gutov <dmitry <at> gutov.dev>, 63648 <at> debbugs.gnu.org, sbaugh <at> catern.com
Subject: Re: bug#63648: 29.0.90; project.el: with switch-use-entire-map,
 switch-project errors on non-project commands
Date: Sun, 03 Sep 2023 20:11:57 +0300
> Thinking about it, I guess there's (roughly) two classes of commands
> which want different things from default-directory, classes 1 and 2:
>
> 1. wants whatever the current value of default-directory is (and gets
> this by just using default-directory as a variable)
>
> 2. wants the value of default-directory for some specific buffer X (and
> gets this either with buffer-local-value or by using
> with-current-buffer)
>
> If we could change 1 without changing 2, then we'd be happy.

I think we can't solve this logical paradox because it contains
self-contradictory requirements.  Here is the command that
illustrates this paradox.  What should this command print?

  C-x p p ... C-h v default-directory RET

Like Schrödinger's cat, it belongs simultaneously to both classes:

1. wants to print the new value of default-directory
   because 'C-h v' is the next command for which
   the value of default-directory was explicitly set.

2. wants to print the original value of default-directory
   because 'C-h v' was invoked in the buffer where
   the value of default-directory should stay unchanged.




This bug report was last modified 1 year and 200 days ago.

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