Dependency architecture restrictions must be non-empty

An empty list of architectures doesn't make sense and has an
ambiguous meaning, so just make it a syntax error.

Closes: #498300

diff --git a/policy.sgml b/policy.sgml
index c1ff4b4ce5f9aadf2801408f4b077ff25e0b57a8..0f1dbf91d54478b958992a073e77e36e7ae83867 100644 (file)
--- a/policy.sgml
+++ b/policy.sgml
@@ -4628,7 +4628,7 @@ Depends: libc6 (>= 2.2.1), exim | mail-transport-agent
          Relationships may be restricted to a certain set of
          architectures.  This is indicated in brackets after each
          individual package name and the optional version specification.
-         The brackets enclose a list of Debian architecture names
+         The brackets enclose a non-empty list of Debian architecture names
          in the format described in <ref id="arch-spec">,
          separated by whitespace.  Exclamation marks may be prepended to
          each of the names.  (It is not permitted for some names to be