Give MAC-less feeds a distinct UID instead of a shared placeholder

[ampledata]

Fixes the remaining Unknown-BasicID_0 case, measured on live hardware.

The problem

Serial/MAVLink receivers (DroneScout Bridge, SiK) report no MAC at all, so a Location- or System-only message from one has neither a MAC nor a serial to identify it, and rendered under the shared Unknown-BasicID_0 placeholder — which collides across every such source.

Measured on a DroneScout Bridge feeding dronecot-dronescout, watching Mesh SA:

57  RID.1787F04BM24010011195.uas   <- correct
57  op-1787F04BM24010011195        <- correct
 3  op-Unknown-BasicID_0           <- the gap

The fix

_rid_identity() falls back to the feed/sensor id (FEED-<sensor_id>) before the placeholder, so unidentified contacts from different receivers stay distinct instead of piling onto one track.

What I tried first, and why it is not here

My initial approach was to key aggregation on the feed when no MAC or serial exists. It is wrong twice over, and I only found out by testing it:

1. It splits rather than merges. A BasicID message keys on the serial while a Location message from the same aircraft keys on the feed — two tracks, neither completing:

r1 (BasicID msg)  key = ('rid', 'SERIAL9')
r2 (Location msg) key = ('feed', 'dronescout')
tracks: 2

2. Worse, it would merge distinct aircraft. One DroneScout receiver reports many drones over a single port, so a feed key would collapse them into one track — exactly the bug this module was written to fix, reintroduced by another route.

So a record with neither MAC nor serial still passes through unaggregated; only its rendered UID changes. track_key() now carries a comment explaining why the tempting fallback is deliberately absent, and a test asserts it stays absent:

def test_feed_is_NOT_used_as_an_aggregation_key(self):
    """Guard against merging distinct aircraft from one multi-drone feed."""
    self.assertIsNone(rid_track.track_key(rid),
        "a MAC-less, serial-less record must not be keyed on its feed")

Tests

66 pass, zero warnings. New cases cover the feed-derived UID, two receivers staying distinct, serial still winning over feed, MAC still winning over both, and the negative assertion above.

🤖 Generated with Claude Code

https://claude.ai/code/session_0197da7dhvcPoHxYKamrYqyM