bug#74105: 30.0.92; Some issues in TRAMP NEWS entries

bug#74105: 30.0.92; Some issues in TRAMP NEWS entries

[Sean Whitton]

X-debbugs-cc: michael.albinus@gmx.de

Hello,

In NEWS we have

    +++
    *** Direct asynchronous processes are indicated by a connection-local variable.
    If direct asynchronous processes shall be used, set the connection-local
    variable 'tramp-direct-async-process' to a non-nil value.  This has been
    changed, in previous Emacs versions this was indicated by the now
    deprecated connection property "direct-async-process".  See the Tramp
    manual "(tramp) Improving performance of asynchronous remote processes".

In my init.el I have this:

    (with-eval-after-load 'tramp
      (add-to-list 'tramp-connection-properties
                   '("/ssh:" "direct-async-process" t))
      (add-to-list 'tramp-connection-properties '(nil "session-timeout" nil)))

I have some documentation issues:

(1) The NEWS entry, together with the Info manual, were not sufficient
    for me to figure how to migrate my config.  For example, is the
    whole of tramp-connection-properties being replaced?  Or do I only
    need to migrate the direct-async-process part?

    I think additional documentation, even an explicit migration guide,
    would be desirable.

(2) Turning on direct async processes for all SSH connections seems like
    a common configuration.  How about adding that to the manual, in
    addition to the example for enabling them for one host?

(3) Has there been a change to how password caching works?

    I tried deleting the session-timeout configuration.  I made a
    /sudo:: connection.  After some time passed, I saw the familiar
    "Tramp connection timed out" message.  But it reconnected
    immediately when I tried to save a buffer I had open.  Does it now
    cache the sudo password?  In the past, you had to type it again,
    after the timeout.

    If there is a change here, it's security-relevant, so it should
    probably be in NEWS.

Thanks.

-- 
Sean Whitton

bug#74105: 30.0.92; Some issues in TRAMP NEWS entries

[Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Sean Whitton <spwhitton@spwhitton.name> writes:

> Hello,

Hi Sean,

thank you for your report.

> In NEWS we have
>
>     +++
>     *** Direct asynchronous processes are indicated by a connection-local variable.
>     If direct asynchronous processes shall be used, set the connection-local
>     variable 'tramp-direct-async-process' to a non-nil value.  This has been
>     changed, in previous Emacs versions this was indicated by the now
>     deprecated connection property "direct-async-process".  See the Tramp
>     manual "(tramp) Improving performance of asynchronous remote processes".
>
> In my init.el I have this:
>
>     (with-eval-after-load 'tramp
>       (add-to-list 'tramp-connection-properties
>                    '("/ssh:" "direct-async-process" t))
>       (add-to-list 'tramp-connection-properties '(nil "session-timeout" nil)))
>
> I have some documentation issues:
>
> (1) The NEWS entry, together with the Info manual, were not sufficient
>     for me to figure how to migrate my config.  For example, is the
>     whole of tramp-connection-properties being replaced?  Or do I only
>     need to migrate the direct-async-process part?

No, the whole tramp-connection-properties machinery is not replaced,
otherwise it would have been mentioned in NEWS. Furthermore, it is still
explained in the Tramp info manual of Emacs 30, which could give you an
indication that it still exists.

>     I think additional documentation, even an explicit migration guide,
>     would be desirable.

What you need to set is described in the Tramp manual. That's why the
quoted NEWS entry says

--8<---------------cut here---------------start------------->8---
See the Tramp manual "(tramp) Improving performance of asynchronous
remote processes".
--8<---------------cut here---------------end--------------->8---

That doesn't need a migration guide.

> (2) Turning on direct async processes for all SSH connections seems like
>     a common configuration.  How about adding that to the manual, in
>     addition to the example for enabling them for one host?

I don't know whether it is common praxis. I, for example, access my NAS
boxes (QNAP) via ssh w/o direct async processes. Simply, because they
are special, and do not cooperate well with direct async processes.

Furthermore, there are also disadvantages using direct async processes,
which are listed in the Tramp manual (same node as above). This prevents
me from saying, all connections using "ssh" shall use direct async
processes. And what's about "scp"? You can also use direct async
processes for such connections. Would you like to recommend this as well
in general? Where do you want to stop? Recommend "rsync"?

Sorry, but the conditions are more complex than you expect. People shall
find out what's best suited for them.

> (3) Has there been a change to how password caching works?
>
>     I tried deleting the session-timeout configuration.  I made a
>     /sudo:: connection.  After some time passed, I saw the familiar
>     "Tramp connection timed out" message.  But it reconnected
>     immediately when I tried to save a buffer I had open.  Does it now
>     cache the sudo password?  In the past, you had to type it again,
>     after the timeout.
>
>     If there is a change here, it's security-relevant, so it should
>     probably be in NEWS.

Likely, you're trapped by the following change, documented in NEWS.29:

--8<---------------cut here---------------start------------->8---
*** Proper password prompts for methods "doas", "sudo" and "sudoedit".
The password prompts for these methods reflect now the credentials of
the user requesting such a connection, and not of the user who is the
target.  This has always been needed, just the password prompt and the
related 'auth-sources' entry were wrong.
--8<---------------cut here---------------end--------------->8---

If it is something else, we need to debug.

> Thanks.

Best regards, Michael.