chore(vector-core): remove fanout pass-by-value lint allow

[arfa79]

Summary

Removes the clippy::needless_pass_by_value suppression from SendGroup::add by borrowing the component key and cloning it only when inserting it into the sender map.

References

Related: #23659

Vector configuration

Not applicable; this is an internal refactor with no configuration changes.

How did you test this PR?

• cargo test -p vector-core fanout --lib
• cargo clippy -p vector-core --lib -- -D warnings
• cargo fmt --all -- --check
• git diff --check

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

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[Copilot]

🟢 Approval recommended

The change is a small, low-risk internal refactor that preserves behavior while removing a Clippy suppression.

Pull request overview

This PR refactors vector-core’s fanout control-message handling to remove a clippy::needless_pass_by_value suppression in SendGroup::add, changing the method to borrow the component key and clone only when inserting into the sender map.

Changes:

• Update SendGroup::add to take &ComponentKey and remove the clippy::needless_pass_by_value allow.
• Adjust the in-flight control-message Add handling to pass &id into SendGroup::add.

File summaries

File	Description
lib/vector-core/src/fanout.rs	Removes a Clippy suppression by switching SendGroup::add to take a borrowed key and cloning for insertion into the sender map.

Review details

Suppressed comments (1)

lib/vector-core/src/fanout.rs:384

• SendGroup::add now takes &ComponentKey and clones it to insert into self.senders. Since ControlMessage::Add already yields an owned ComponentKey, this introduces an avoidable allocation on every add (because ComponentKey clones its inner String). Consider switching SendGroup::add back to taking id: ComponentKey and moving it into the IndexMap (similar to Fanout::add), which removes the need for both the clone and the previous clippy suppression.

        // When we're in the middle of a send, we can only keep track of the new sink, but can't
        // actually send to it, as we don't have the item to send... so only add it to `senders`.
        assert!(
            self.senders
                .insert(id.clone(), Some(Sender::new(sink)))

• Files reviewed: 1/1 changed files
• Comments generated: 0
• Review effort level: Lite

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[thomasqueirozb]

Thanks!