Greetings APT developers,

Whilst maintaining oma (https://github.com/AOSC-Dev/oma), a package
management frontend based on libapt-pkg, we ran into multiple user
reports that oma is unable to handled comma-separated items in the
"Architectures:" entry.

Take for example this .sources file from Cursor:

   ### THIS FILE IS AUTOMATICALLY CONFIGURED ###
   # You may comment out this entry, but any other modifications may be
lost.
   Types: deb
   URIs: https://downloads.cursor.com/aptrepo
   Suites: stable
   Components: main
   Architectures: amd64,arm64
   Signed-By: /usr/share/keyrings/anysphere.gpg

We see that the two architectures are listed in a comma-separated
fashion. However, sources.list(5) specifies that:

   Note especially that multiple values are separated  by  whitespaces
   (like spaces, tabs and newlines), not by commas as in the one-line
   format.

Meaning that the example above should be invalid and rejected by APT,
but it was in fact allowed. Following this specification, oma was
implemented in a way which it returns a warning and does not treat
commas as separators:

     WARNING Mirror https://downloads.cursor.com/aptrepo does not
contain architectures enabled in local configuration ('amd64' 'i386'
enabled, 'amd64,arm64' available from the mirror)

Whereas APT accepts this source configuration just fine...

APT maintainers, would you please clarify on the usage of commas in
DEB822 sources? It would be very helpful as we are currently not sure as
to whether we should heed to the manpages or the de facto implementation
currently found in APT.

Best Regards,
Mingcong Bai

You'll find that APT is generally more liberal in what it accepts than
what it specifies is the correct format, and figuring out all the lose
ends and carefully and slowly deprecating them is painful.