Bug#1136160: debian-policy: Clarify that Multi-Arch is not applicable for udebs

On 10/05/26 8:46 pm, Helmut Grohne wrote:
> Generally, I agree with the intent of this change. I do not anticipate
> any use of Multi-Arch in the installer. In particular, the way it is
> built does not consider this field in any way.
> 
> Now "must not" is strong for a field that is ignored. I checked the
> amd64 main Packages file and the "must not" would render at least 9 font
> packages rc-buggy. Their use of this field presently does not cause
> immediate problems as far as I can see.
> 
> I kinda like the way this is expressed for the Standards-Version:
> 
>     udebs and source packages that only produce udebs do not use Standards-Version.
> 
> How about borrowing the wording there?

I was planning to use something similar, but the messages in the IRC mentioned must not, and hence I
decided to choose this instead :)

This will still result in 9 bugs, but not with rc severity. The train of thought above makes
sense to me.

> I am hesitant to second the "must not" precisely for those font
> packages.

Attached another patch, with wording changed a bit; as M-A is relevant only for binary package
stanza (and S-V makes it to only source package stanza which would be sort of inherited).
Please see if this is good enough.

Best,
Nilesh

diff --git a/policy/ch-controlfields.rst b/policy/ch-controlfields.rst
index 69467c4..92d4dbe 100644
--- a/policy/ch-controlfields.rst
+++ b/policy/ch-controlfields.rst
@@ -1381,8 +1381,9 @@ A Debian installation can combine packages from multiple architectures.
 The ``Multi-Arch`` field enables individual packages to declare their
 support for this feature, and influences the way dependencies are
 handled.  It can be declared in binary package sections of a source
-package template control file and in binary package control files.  The
-permitted field values are ``no`` (default), ``foreign``, ``same`` and
+package template control file and in binary package control files.
+Binary package stanzas for udebs do not make use of ``Multi-Arch``.
+The permitted field values are ``no`` (default), ``foreign``, ``same`` and
 ``allowed``. Their semantics are described in the following sections.
 
 .. _s-f-Multi-Arch-no: