Preferred contents based on presence in repo

For preferred content expressions, is there an option analogous to the "--in=repo" matching option?

I was surprised not to find it, but maybe I have overlooked something.

Many thanks

You could use the approach mentioned in the preferred-content manpage:

Preferred content expressions have no equivalent to the `--in`
option, but groups can accomplish similar things. You can add
repositories to groups, and match against the groups in a
preferred content expression. So rather than `--in=usbdrive`,
put all the USB drives into a "transfer" group, and use
`copies=transfer:1`

Comment by kyle — Thu Mar 5 20:26:01 2020

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comment 2

Thanks, I missed that in the man page.

Is there a rationale for not having the option for preferred contents?

Comment by erewhon — Sat Mar 7 23:14:56 2020

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re: rationale

Is there a rationale for not having the option for preferred contents?

Hmm, I wouldn't be able to answer this myself, but digging around a bit it looks like there used to be an in= option. Here's the rationale given in that commit:

CommitDate: Fri Oct 19 16:09:21 2012 -0400
40aab719dfe9c3bd240656c1ff387cad0ba8d96d

Replace "in=" with "present" in preferred content expressions

in= was problimatic in two ways. First, it referred to a remote by name,
but preferred content expressions can be evaluated elsewhere, where that
remote doesn't exist, or a different remote has the same name. This name
lookup code could error out at runtime. Secondly, in= seemed pretty useless.
in=here did not cause content to be gotten, but it did let present content
be dropped.

present is more useful, although "not present" is unstable and should be
avoided.

Comment by kyle — Mon Mar 9 22:17:51 2020

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