From e935d6a86edec410ba2cae35000bbf4943aa00b1 Mon Sep 17 00:00:00 2001
From: Julian Simioni <julian@simioni.org>
Date: Wed, 3 Dec 2025 10:20:57 -0500
Subject: [PATCH] feat(dedupe): Prefer country over locality when deduping

This is a simple change to prefer country records over localities when
we are deduplicating two matching records.

Note that this doesn't change _when_ deduplication will occur, just
which record we prefer when doing so and having identified two records
as duplicates.

It mostly affects city-states and small countries like Singapore,
Hong-Kong, etc. Some not-quite-city-states like Luxembourg are also
affected.

It's a bit of a stylistic change, in these cases either the country or
locality is _technically_ correct.

Some things this fixes:
- Previously, Mexico City and Meixco were both deduplicated to Mexico
  City. Thus there was nothing you could type in to get Mexico the
  country. Now, you'll get the country until you type 'Mexico C'. This
  is still not ideal, we really should not deduplicate those two
  records, but for now this is at least better.
- We've found there are some junk locality records out there that match
  country names, and this conveniently removes all of them.
---
 helper/diffPlaces.js           | 2 +-
 test/unit/middleware/dedupe.js | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/helper/diffPlaces.js b/helper/diffPlaces.js
index ff02f99de..c9c7ea5ab 100644
--- a/helper/diffPlaces.js
+++ b/helper/diffPlaces.js
@@ -10,8 +10,8 @@ const codec = require('pelias-model').codec;
 // when performing inter-layer deduping, layers coming earlier in this list take
 // preference to those appearing later.
 const layerPreferences = [
-  'locality',
   'country',
+  'locality',
   'localadmin',
   'county',
   'region',
diff --git a/test/unit/middleware/dedupe.js b/test/unit/middleware/dedupe.js
index 786116f7d..f8872ee4b 100644
--- a/test/unit/middleware/dedupe.js
+++ b/test/unit/middleware/dedupe.js
@@ -519,7 +519,7 @@ module.exports.tests.priority = function(test, common) {
     var expectedCount = 1;
     dedupe(req, res, function () {
       t.equal(res.data.length, expectedCount, 'results have fewer items than before');
-      t.deepEqual(res.data[0].layer, 'locality', 'locality result won');
+      t.deepEqual(res.data[0].layer, 'country', 'country result won');
       t.end();
     });
   });