emacs in ~/.cache

emacs in ~/.cache

[Colin Baxter]

I've noticed that emacs now puts a directory into ~/.cache. This is in
Debian but I assume emacs in other systems are behave the same. I think
that ~/.cache/emacs is fairly new, perhaps beginning emacs-28, but I am
not certain.

I have never seen ~/.cache/emacs populated with anything, so what is its
purpose?

Colin Baxter.

Re: emacs in ~/.cache

[Eli Zaretskii]

> From: Colin Baxter <m43cap@yandex.com>
> Date: Sun, 13 Aug 2023 13:17:25 +0100
> 
> 
> I've noticed that emacs now puts a directory into ~/.cache. This is in
> Debian but I assume emacs in other systems are behave the same. I think
> that ~/.cache/emacs is fairly new, perhaps beginning emacs-28, but I am
> not certain.
> 
> I have never seen ~/.cache/emacs populated with anything, so what is its
> purpose?

Some distros insist on putting the *.eln files in XDG_CACHE_DIR, which
defaults to ~/.cache.  I guess Debian is one of them.  Too bad
(IMNSHO), but they cannot be bothered.

Re: emacs in ~/.cache

[Colin Baxter]

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

    >> From: Colin Baxter <m43cap@yandex.com> Date: Sun, 13 Aug 2023
    >> 13:17:25 +0100
    >> 
    >> 
    >> I've noticed that emacs now puts a directory into ~/.cache. This
    >> is in Debian but I assume emacs in other systems are behave the
    >> same. I think that ~/.cache/emacs is fairly new, perhaps
    >> beginning emacs-28, but I am not certain.
    >> 
    >> I have never seen ~/.cache/emacs populated with anything, so what
    >> is its purpose?

    > Some distros insist on putting the *.eln files in XDG_CACHE_DIR,
    > which defaults to ~/.cache.  I guess Debian is one of them.  Too
    > bad (IMNSHO), but they cannot be bothered.

Thanks for the information. I never compile emacs with
native-compilation enabled. But if I did then I don't think I'd want the
.eln files anywhere near $HOME/.cache, which gets deleted on my system
every re-boot.

Colin.

Re: emacs in ~/.cache

[Eli Zaretskii]

> From: Colin Baxter <m43cap@yandex.com>
> Date: Sun, 13 Aug 2023 16:43:21 +0100
> 
> >>>>> Eli Zaretskii <eliz@gnu.org> writes:
> 
>     > Some distros insist on putting the *.eln files in XDG_CACHE_DIR,
>     > which defaults to ~/.cache.  I guess Debian is one of them.  Too
>     > bad (IMNSHO), but they cannot be bothered.
> 
> Thanks for the information. I never compile emacs with
> native-compilation enabled. But if I did then I don't think I'd want the
> .eln files anywhere near $HOME/.cache, which gets deleted on my system
> every re-boot.

Exactly my point.

Re: emacs in ~/.cache

[Sven Joachim]

On 2023-08-13 15:24 +0300, Eli Zaretskii wrote:

>> From: Colin Baxter <m43cap@yandex.com>
>> Date: Sun, 13 Aug 2023 13:17:25 +0100
>>
>>
>> I've noticed that emacs now puts a directory into ~/.cache. This is in
>> Debian but I assume emacs in other systems are behave the same. I think
>> that ~/.cache/emacs is fairly new, perhaps beginning emacs-28, but I am
>> not certain.
>>
>> I have never seen ~/.cache/emacs populated with anything, so what is its
>> purpose?
>
> Some distros insist on putting the *.eln files in XDG_CACHE_DIR, which
> defaults to ~/.cache.  I guess Debian is one of them.

Well, that guess was wrong.  The *.eln files are put into
~/.emacs.d/eln-cache.

> Too bad (IMNSHO), but they cannot be bothered.

You have certainly no obligation whatsoever to contact the Debian Emacs
maintainers, but please do not discourage others from doing so if they
have Debian-specific problems.

Cheers,
       Sven

Re: emacs in ~/.cache

[Michael Albinus]

Colin Baxter <m43cap@yandex.com> writes:

Hi,

> I've noticed that emacs now puts a directory into ~/.cache. This is in
> Debian but I assume emacs in other systems are behave the same. I think
> that ~/.cache/emacs is fairly new, perhaps beginning emacs-28, but I am
> not certain.
>
> I have never seen ~/.cache/emacs populated with anything, so what is its
> purpose?

Tramp 2.7 (of Emacs 30) uses ~/.cache/emacs as temporary directory, if
possible. The reason are security considerations.

> Colin Baxter.

Best regards, Michael.

Re: emacs in ~/.cache

[Colin Baxter]

>>>>> Michael Albinus <michael.albinus@gmx.de> writes:

    > Colin Baxter <m43cap@yandex.com> writes: Hi,

    >> I've noticed that emacs now puts a directory into ~/.cache. This
    >> is in Debian but I assume emacs in other systems are behave the
    >> same. I think that ~/.cache/emacs is fairly new, perhaps
    >> beginning emacs-28, but I am not certain.
    >> 
    >> I have never seen ~/.cache/emacs populated with anything, so what
    >> is its purpose?

    > Tramp 2.7 (of Emacs 30) uses ~/.cache/emacs as temporary
    > directory, if possible. The reason are security considerations.

I have

--8<---------------cut here---------------start------------->8---

(setq tramp-auto-save-directory "$HOME/.emacs.d/tmp")
(setq temporary-file-directory "$HOME/.emacs.d/tmp")

--8<---------------cut here---------------end--------------->8---

Presumably that's ok, as far as tramp is concerned?

Colin.

Re: emacs in ~/.cache

[Michael Albinus]

Colin Baxter <m43cap@yandex.com> writes:

Hi Colin,

> I have
>
> (setq tramp-auto-save-directory "$HOME/.emacs.d/tmp")
> (setq temporary-file-directory "$HOME/.emacs.d/tmp")
>
> Presumably that's ok, as far as tramp is concerned?

For Tramp's business, you need to set also
tramp-compat-temporary-file-directory.

> Colin.

Best regards, Michael.

Re: emacs in ~/.cache

[Colin Baxter]

>>>>> Michael Albinus <michael.albinus@gmx.de> writes:

    > Colin Baxter <m43cap@yandex.com> writes: Hi Colin,

    >> I have
    >> 
    >> (setq tramp-auto-save-directory "$HOME/.emacs.d/tmp") (setq
    >> temporary-file-directory "$HOME/.emacs.d/tmp")
    >> 
    >> Presumably that's ok, as far as tramp is concerned?

    > For Tramp's business, you need to set also
    > tramp-compat-temporary-file-directory.

Thanks. I'll set that to $HOME/.emacs.d/tmp too.

Best wishes,

Colin Baxter.

Re: emacs in ~/.cache

[Emanuel Berg]

Michael Albinus wrote:

>> I have never seen ~/.cache/emacs populated with anything,
>> so what is its purpose?
>
> Tramp 2.7 (of Emacs 30) uses ~/.cache/emacs as temporary
> directory, if possible. The reason are
> security considerations.

I have a Tramp socket file there on Debian, it is the
only file.

It gets more secure that way?

What happens if you remove that directory, will it still work
the next time, just a similar file has to be created first
before use?

-- 
underground experts united
https://dataswamp.org/~incal

Re: emacs in ~/.cache

[Michael Albinus]

Emanuel Berg <incal@dataswamp.org> writes:

Hi Emanuel,

>> Tramp 2.7 (of Emacs 30) uses ~/.cache/emacs as temporary
>> directory, if possible. The reason are
>> security considerations.
>
> I have a Tramp socket file there on Debian, it is the
> only file.
>
> It gets more secure that way?

~/.cache has 0700 file permissions. Other users have no access.

> What happens if you remove that directory, will it still work
> the next time, just a similar file has to be created first
> before use?

If you remove it while Emacs is running you're lost. Don't do that!

When Tramp is loaded, and ~/.cache exists, ~/.cache/emacs will be
(re-)created if it doesn't exist. Otherwise, /tmp will be used (or
whatever value of temporary-file-directory).

See the initialization of tramp-compat-temporary-file-directory in
tramp-compat.el.

Best regards, Michael.

Re: emacs in ~/.cache

[Emanuel Berg]

Michael Albinus wrote:

>>> Tramp 2.7 (of Emacs 30) uses ~/.cache/emacs as temporary
>>> directory, if possible. The reason are
>>> security considerations.
>>
>> I have a Tramp socket file there on Debian, it is the
>> only file.
>>
>> It gets more secure that way?
>
> ~/.cache has 0700 file permissions. Other users have
> no access.
>
>> What happens if you remove that directory, will it still
>> work the next time, just a similar file has to be created
>> first before use?
>
> If you remove it while Emacs is running you're lost.
> Don't do that!
>
> When Tramp is loaded, and ~/.cache exists, ~/.cache/emacs
> will be (re-)created if it doesn't exist. Otherwise, /tmp
> will be used (or whatever value of
> temporary-file-directory).
>
> See the initialization of
> tramp-compat-temporary-file-directory in tramp-compat.el.

Thank you, this was a pleasant explanation.

-- 
underground experts united
https://dataswamp.org/~incal