shepherd 1.0.2 --help: warning: call to environ while multiple threads are running; further behavior unspecified.

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3 participants

Ludovic Courtès
Simon Josefsson
Tomas Volf

Owner: unassigned

Submitted by: Simon Josefsson

Severity: normal

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Simon Josefsson wrote 3 weeks ago

Recipients:(address . bug-guix@gnu.org)

Message-ID:87bjv1lruw.fsf@josefsson.org

It seems shepherd in Debian print the following on a simple --help:

132s warning: call to environ while multiple threads are running;

132s further behavior unspecified.

I can't find the error message in guile-fibers or shepherd source code.

Any ideas where it comes from and how to fix it?

Version 1.0.0:

https://ci.debian.net/packages/s/shepherd/testing/amd64/57880388/

Version 1.0.2:

https://salsa.debian.org/debian/shepherd/-/jobs/7101207#L718

/Simon

Tomas Volf wrote 3 weeks ago

Recipients:(name . Simon Josefsson via Bug reports for GNU Guix)(address . bug-guix@gnu.org)

Message-ID:87wmdp36ry.fsf@wolfsden.cz

Simon Josefsson via Bug reports for GNU Guix <bug-guix@gnu.org> writes:

Toggle quote (10 lines)> Hi
>
> It seems shepherd in Debian print the following on a simple --help:
>
> 132s warning: call to environ while multiple threads are running;
> 132s          further behavior unspecified.
>
> I can't find the error message in guile-fibers or shepherd source code.
> Any ideas where it comes from

Guile itself, libguile/posix.c.

Toggle snippet (10 lines)

libguile/posix.c

1724- if (scm_ilength (scm_all_threads ()) != 1)

1725- scm_display

1726- (scm_from_latin1_string

1727: ("warning: call to environ while multiple threads are running;\n"

1728- " further behavior unspecified.\n"),

1729- scm_current_warning_port ());

1730-

Toggle quote (2 lines)

> and how to fix it?

Do not call (environ) when multiple threads are running, but I assume

that is not actually helpful advice. :)

Toggle quote (10 lines)>
> Version 1.0.0:
> https://ci.debian.net/packages/s/shepherd/testing/amd64/57880388/
>
> Version 1.0.2:
> https://salsa.debian.org/debian/shepherd/-/jobs/7101207#L718
>
> /Simon
>

-- 
There are only two hard things in Computer Science:
cache invalidation, naming things and off-by-one errors.

Simon Josefsson wrote 3 weeks ago

Recipients:(name . Tomas Volf)(address . ~@wolfsden.cz)

Message-ID:87tt8th3d1.fsf@josefsson.org

Tomas Volf <~@wolfsden.cz> writes:

Toggle quote (28 lines)> Simon Josefsson via Bug reports for GNU Guix <bug-guix@gnu.org> writes:
>
>> Hi
>>
>> It seems shepherd in Debian print the following on a simple --help:
>>
>> 132s warning: call to environ while multiple threads are running;
>> 132s          further behavior unspecified.
>>
>> I can't find the error message in guile-fibers or shepherd source code.
>> Any ideas where it comes from
>
> Guile itself, libguile/posix.c.
>
> libguile/posix.c
> 1724-  if (scm_ilength (scm_all_threads ()) != 1)
> 1725-    scm_display
> 1726-      (scm_from_latin1_string
> 1727:       ("warning: call to environ while multiple threads are running;\n"
> 1728-        "         further behavior unspecified.\n"),
> 1729-       scm_current_warning_port ());
> 1730-
>
>> and how to fix it?
>
> Do not call (environ) when multiple threads are running, but I assume
> that is not actually helpful advice. :)

Thank you for the pointer. Interesting - why isn't this triggered on

Guix but only when building shepherd on a foreign distribution like

Debian?

Is the message really correct? I thought guile-fibers and shepherd did

not use threads at all.

If it is possible to make --help and --version avoid launching new

threads, that would be nice to resolve this warning for at least the

simple use-case of doing --help and --version.

/Simon

Toggle quote (9 lines)>>
>> Version 1.0.0:
>> https://ci.debian.net/packages/s/shepherd/testing/amd64/57880388/
>>
>> Version 1.0.2:
>> https://salsa.debian.org/debian/shepherd/-/jobs/7101207#L718
>>
>> /Simon
>>

Ludovic Courtès wrote 2 weeks ago

Recipients:(name . Simon Josefsson)(address . simon@josefsson.org)(address . 76343@debbugs.gnu.org)

Message-ID:87frk03dss.fsf@gnu.org

Hi,

Simon Josefsson <simon@josefsson.org> skribis:

Toggle quote (5 lines)

> It seems shepherd in Debian print the following on a simple --help:

> 132s warning: call to environ while multiple threads are running;

> 132s further behavior unspecified.

This is a bug introduced in Guile 3.0.10 (Guix still uses 3.0.9), for

which I’ve now sent a patch:

https://issues.guix.gnu.org/76589

Olivier Dion submitted another patch, which complements the one above:

https://lists.gnu.org/archive/html/guile-devel/2025-02/msg00036.html

Thanks,

Ludo’.

Simon Josefsson wrote 2 weeks ago

Recipients:(name . Ludovic Courtès)(address . ludo@gnu.org)(address . 76343@debbugs.gnu.org)

Message-ID:270FEE5B-1373-4060-92BC-B205BF867948@josefsson.org

Thank you! Does this make shepherd Debian packages useless, or can we suggest people to ignore the warning? Any simple way to patch it out from within shepherd? The Debian freeze is in two weeks and it would be nice to give a good first impression to people try it shepherd from Debian… i could try to get guile patched, but it is getting late.

/Simon

Toggle quote (22 lines)> 26 feb. 2025 kl. 16:51 skrev Ludovic Courtès <ludo@gnu.org>:
> 
> ﻿Hi,
> 
> Simon Josefsson <simon@josefsson.org> skribis:
> 
>> It seems shepherd in Debian print the following on a simple --help:
>> 
>> 132s warning: call to environ while multiple threads are running;
>> 132s          further behavior unspecified.
> 
> This is a bug introduced in Guile 3.0.10 (Guix still uses 3.0.9), for
> which I’ve now sent a patch:
> 
>  https://issues.guix.gnu.org/76589
> 
> Olivier Dion submitted another patch, which complements the one above:
> 
>  https://lists.gnu.org/archive/html/guile-devel/2025-02/msg00036.html
> 
> Thanks,
> Ludo’.

Ludovic Courtès wrote 2 weeks ago

Recipients:(name . Simon Josefsson)(address . simon@josefsson.org)(address . 76343@debbugs.gnu.org)

Message-ID:871pvjwdym.fsf@gnu.org

Hi Simon,

Simon Josefsson <simon@josefsson.org> skribis:

Toggle quote (2 lines)

> Thank you! Does this make shepherd Debian packages useless, or can we suggest people to ignore the warning? Any simple way to patch it out from within shepherd? The Debian freeze is in two weeks and it would be nice to give a good first impression to people try it shepherd from Debian… i could try to get guile patched, but it is getting late.

A simple way would be to patch out the ‘environ’ warning in Guile: it

didn’t exist before 3.0.10, it’s bogus (it fires even when you’re not

mutating the environment and even with just a single user thread, as is

the case here), and the comment itself doesn’t change program behavior.

If that’s not adequate, we could try and come up with a quick hack for

shepherd to avoid the ‘environ’ call at the top-level (though that’s

probably not something I would consider for inclusion in the Shepherd

proper.)

WDYT?

Ludo’.

Simon Josefsson wrote 1 weeks ago

Recipients:(name . Ludovic Courtès)(address . ludo@gnu.org)(address . 76343@debbugs.gnu.org)

Message-ID:ed0ebcbceec6108ae89725c79e6a9737862e05bb.camel@josefsson.org

tor 2025-02-27 klockan 17:26 +0100 skrev Ludovic Courtès:

Toggle quote (24 lines)> Hi Simon,
> 
> Simon Josefsson <simon@josefsson.org> skribis:
> 
> > Thank you! Does this make shepherd Debian packages useless, or can
> > we suggest people to ignore the warning? Any simple way to patch it
> > out from within shepherd? The Debian freeze is in two weeks and it
> > would be nice to give a good first impression to people try it
> > shepherd from Debian… i could try to get guile patched, but it is
> > getting late.
> 
> A simple way would be to patch out the ‘environ’ warning in Guile: it
> didn’t exist before 3.0.10, it’s bogus (it fires even when you’re not
> mutating the environment and even with just a single user thread, as
> is
> the case here), and the comment itself doesn’t change program
> behavior.
> 
> If that’s not adequate, we could try and come up with a quick hack
> for
> shepherd to avoid the ‘environ’ call at the top-level (though that’s
> probably not something I would consider for inclusion in the Shepherd
> proper.)

A shephard-specific patch would be the simplest at this point, I think.

Do you have some idea how to do that? I agree it seems like a Debian-

specific patch for now.

OTOH, maybe this is not critical. It is a stderr warning message. But

it does look ugly, and may give a bad first impression for Debian

people migrating towards Guix.

/Simon

Ludovic Courtès wrote 1 weeks ago

Recipients:(name . Simon Josefsson)(address . simon@josefsson.org)(address . 76343@debbugs.gnu.org)

Message-ID:87r03cajp9.fsf@gnu.org

Hi,

Simon Josefsson <simon@josefsson.org> skribis:

Toggle quote (5 lines)

> A shephard-specific patch would be the simplest at this point, I think.

> Do you have some idea how to do that? I agree it seems like a Debian-

> specific patch for now.

The patch below appears to do the trick. I guess I could just as well

integrate it in the next 1.0.x bug-release.

Does it work for you?

Thanks,

Ludo’.

Toggle diff (30 lines)diff --git a/modules/shepherd.scm b/modules/shepherd.scm
index d55373a..a35a415 100644
--- a/modules/shepherd.scm
+++ b/modules/shepherd.scm
@@ -515,7 +515,11 @@ fork in the child process."
                          ;; stdout.  Redirect stdout to the bitbucket so we
                          ;; don't log twice.
                          (%make-void-port "w")
-                         (current-output-port)))))
+                         (current-output-port))))
+
+                   ;; In Guile 3.0.10, calling 'environ' from the top-level
+                   ;; triggers a warning so do it from here.
+                   (default-environment-variables (environ)))
 
       (parameterize ((current-output-port (%current-service-output-port)))
         (set-port-encoding! (log-output-port) "UTF-8")
diff --git a/modules/shepherd/service.scm b/modules/shepherd/service.scm
index 2d64897..c8667e6 100644
--- a/modules/shepherd/service.scm
+++ b/modules/shepherd/service.scm
@@ -1437,7 +1437,7 @@ background:~{ ~a~}."
 (define default-environment-variables
   ;; The default list of environment variable name/value pairs that should be
   ;; set when starting a service.
-  (make-parameter (environ)))
+  (make-parameter '()))
 
 (define default-pid-file-timeout
   ;; Maximum number of seconds to wait for a PID file to show up.

Simon Josefsson wrote 1 weeks ago

Recipients:(name . Ludovic Courtès)(address . ludo@gnu.org)(address . 76343@debbugs.gnu.org)

Message-ID:87tt88sr7w.fsf@josefsson.org

Ludovic Courtès <ludo@gnu.org> writes:

Toggle quote (14 lines)> Hi,
>
> Simon Josefsson <simon@josefsson.org> skribis:
>
>> A shephard-specific patch would be the simplest at this point, I think.
>>  
>> Do you have some idea how to do that?  I agree it seems like a Debian-
>> specific patch for now.
>
> The patch below appears to do the trick.  I guess I could just as well
> integrate it in the next 1.0.x bug-release.
>
> Does it work for you?

It does, yes!

Breaking: https://salsa.debian.org/debian/shepherd/-/jobs/7197263

Working: https://salsa.debian.org/debian/shepherd/-/jobs/7197290

The only difference is your patch. I'll upload this eventually.

Thanks,

/Simon

Toggle quote (35 lines)>
> Thanks,
> Ludo’.
>
> diff --git a/modules/shepherd.scm b/modules/shepherd.scm
> index d55373a..a35a415 100644
> --- a/modules/shepherd.scm
> +++ b/modules/shepherd.scm
> @@ -515,7 +515,11 @@ fork in the child process."
>                           ;; stdout.  Redirect stdout to the bitbucket so we
>                           ;; don't log twice.
>                           (%make-void-port "w")
> -                         (current-output-port)))))
> +                         (current-output-port))))
> +
> +                   ;; In Guile 3.0.10, calling 'environ' from the top-level
> +                   ;; triggers a warning so do it from here.
> +                   (default-environment-variables (environ)))
>  
>        (parameterize ((current-output-port (%current-service-output-port)))
>          (set-port-encoding! (log-output-port) "UTF-8")
> diff --git a/modules/shepherd/service.scm b/modules/shepherd/service.scm
> index 2d64897..c8667e6 100644
> --- a/modules/shepherd/service.scm
> +++ b/modules/shepherd/service.scm
> @@ -1437,7 +1437,7 @@ background:~{ ~a~}."
>  (define default-environment-variables
>    ;; The default list of environment variable name/value pairs that should be
>    ;; set when starting a service.
> -  (make-parameter (environ)))
> +  (make-parameter '()))
>  
>  (define default-pid-file-timeout
>    ;; Maximum number of seconds to wait for a PID file to show up.
>

Ludovic Courtès wrote 6 days ago

Recipients:(name . Simon Josefsson)(address . simon@josefsson.org)(address . 76343-done@debbugs.gnu.org)

Message-ID:875xkmxjru.fsf@gnu.org

Simon Josefsson <simon@josefsson.org> skribis:

Toggle quote (18 lines)> Ludovic Courtès <ludo@gnu.org> writes:
>
>> Hi,
>>
>> Simon Josefsson <simon@josefsson.org> skribis:
>>
>>> A shephard-specific patch would be the simplest at this point, I think.
>>>  
>>> Do you have some idea how to do that?  I agree it seems like a Debian-
>>> specific patch for now.
>>
>> The patch below appears to do the trick.  I guess I could just as well
>> integrate it in the next 1.0.x bug-release.
>>
>> Does it work for you?
>
> It does, yes!

Excellent. :-)

Pushed in the Shepherd as 8e951de13120729907c527d4a420b579aec944f4.

Thanks!

Ludo’.

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