:new only works in first source

[lrustand]

I'm using consult--multi to select from some custom buffer sources. The help text for consult--multi says that there is a source field named :new, which is a function that is called with a a new entry.

If I add a :new field to the first source in the list passed to consult-multi, then it works as expected, but if I instead add a :new field to any of the sources that are not first in the list it is not executed, even if it is the only source that has a :new field.

[lrustand]

Additionally, it is not possible to add the :new field directly to the consult--multi call. This would probably be even more preferrable.

[minad]

If I add a :new field to the first source in the list passed to consult-multi, then it works as expected, but if I instead add a :new field to any of the sources that are not first in the list it is not executed, even if it is the only source that has a :new field.

No, it also works if you narrow to another source with a :new field. If you don't narrow, the first source wins.

[lrustand]

But why should the first source "win" if it doesn't have anything to win with? Why can't the first source that HAS a :new field win?

[minad]

I find it more consistent like this. The candidates of the first source are also matched first. A source with a :default field is also preferred. See the following code for the order of preference:

consult/consult.el

Lines 2787 to 2794 in e102b10

	(let* ((src (cond
	(narrow (seq-find (lambda (src)
	(let ((n (plist-get src :narrow)))
	(eq (or (car-safe n) n -1) narrow)))
	sources))
	((seq-find (lambda (src) (plist-get src :default)) sources))
	((seq-find (lambda (src) (not (plist-get src :hidden))) sources))
	((aref sources 0))))

You are right that we could prefer a source with a :new field, but then we could get an inconsistency between :default and :new.

...if it doesn't have anything to win with?

The question is which source the candidate will be assigned to - see the return value of consult--multi. The presence of a :new field is orthogonal and only makes it more convenient to add an additional action to execute for new candidates.