From: Philipp Stephani <p.stephani2@gmail.com>
To: Michael Heerdegen <michael_heerdegen@web.de>
Cc: 26624@debbugs.gnu.org
Subject: bug#26624: 26.0.50; Generalized variable `buffer-local-value' does't restore local flag
Date: Sun, 04 Feb 2018 19:01:15 +0000 [thread overview]
Message-ID: <CAArVCkQG3TTXRXrFetLp_j6Cou4HEzYE4w7hfF=Y_YQkOunpKg@mail.gmail.com> (raw)
In-Reply-To: <87mv13mim5.fsf@web.de>
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Michael Heerdegen <michael_heerdegen@web.de> schrieb am Mi., 24. Jan. 2018
um 15:33 Uhr:
> Philipp Stephani <p.stephani2@gmail.com> writes:
>
> > Thanks for this great analysis. Given this, it seems that the place
> > definition for `buffer-local-value' should be removed from gv.el.
>
> But hmm - surely there are other functions where `cl-letf' doesn't
> exactly restore the previous state - `alist-get', for example:
>
> #+begin_src emacs-lisp
> (setq my-alist '((x . 1)))
> (ignore (cl-letf (((alist-get 'y my-alist) 17)) my-alist))
> my-alist
> ==> ((y) (x . 1))
> #+end_src
>
> (admittedly, this is not as serious as the `buffer-local-value' case).
> Also, as another, different problematic case, the manual warns about
> `point' to be used with `cl-letf'.
>
> So, I wonder if, instead of removing the gv-setter definition for
> `buffer-local-value', we should instead add some more text about how
> `cl-letf' can have surprising effects to the manual.
>
>
>
I think we should spend significant efforts to avoid surprises. In this
case, if it means we should remove `alist-get' as well from the forms
supported by `cl-letf', then I think that's what we should do. The
documentation for `cl-letf' clearly states: "On exit, either normally or
because of a ‘throw’ or error, the PLACEs are set back to their original
values." If it can't do that for some place form, it shouldn't be allowed.
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next prev parent reply other threads:[~2018-02-04 19:01 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-23 17:13 bug#26624: 26.0.50; Generalized variable `buffer-local-value' does't restore local flag Philipp Stephani
2017-06-17 13:10 ` Philipp Stephani
2017-06-17 18:48 ` npostavs
2017-06-18 4:17 ` Michael Heerdegen
2017-07-02 16:53 ` Philipp Stephani
2017-09-24 15:19 ` Philipp Stephani
2017-09-24 15:36 ` Michael Heerdegen
2017-09-24 15:44 ` Noam Postavsky
2017-09-24 16:42 ` Philipp Stephani
2017-09-24 17:43 ` Noam Postavsky
2017-09-29 7:50 ` Eli Zaretskii
2017-09-29 20:55 ` Philipp Stephani
2017-09-30 6:46 ` Eli Zaretskii
2017-12-26 22:19 ` Michael Heerdegen
2017-12-27 16:10 ` Eli Zaretskii
2017-12-27 19:54 ` Michael Heerdegen
2017-12-27 20:27 ` Eli Zaretskii
2017-12-29 14:08 ` Michael Heerdegen
2017-12-29 16:14 ` Eli Zaretskii
2017-12-29 16:20 ` Philipp Stephani
2022-08-21 21:38 ` Lars Ingebrigtsen
2022-08-21 22:21 ` Lars Ingebrigtsen
2022-08-22 6:53 ` Michael Heerdegen
2022-08-22 10:10 ` Lars Ingebrigtsen
2022-08-22 21:43 ` Michael Heerdegen
2022-08-23 10:28 ` Lars Ingebrigtsen
2018-01-24 14:33 ` Michael Heerdegen
2018-02-04 19:01 ` Philipp Stephani [this message]
2018-02-04 21:02 ` Michael Heerdegen
2018-02-11 17:54 ` Philipp Stephani
2018-02-11 20:56 ` Michael Heerdegen
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