fix(datacenters): preserve missing geometry and compare ring topology

src/data/datacentersNorwayRefresh.test.mjs

@@ -0,0 +1,93 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { spawnSync } from 'node:child_process';
+import { fileURLToPath } from 'node:url';
+
+const SCRIPT = fileURLToPath(
+  new URL('../../scripts/build-datacenters-norway.py', import.meta.url),
+);
+
+function python(t, source) {
+  const result = spawnSync('python3', ['-c', source, SCRIPT], {
+    encoding: 'utf8',
+  });
+  if (result.error?.code === 'ENOENT') return t.skip('python3 is not installed');
+  assert.equal(result.status, 0, result.stderr);
+}
+
+test('Norway refresh compares rings, not vertex sets', (t) => {
+  python(
+    t,
+    String.raw`
+import runpy, sys
+same = runpy.run_path(sys.argv[1])['same_geometry']
+poly = lambda *rings: {'type': 'Polygon', 'coordinates': list(rings)}
+multi = lambda *polys: {'type': 'MultiPolygon', 'coordinates': [p['coordinates'] for p in polys]}
+a, b, c, d, e = [0, 0], [4, 0], [4, 4], [0, 4], [2, 1]
+assert not same(poly([a, b, c, d, e, a]), poly([a, b, e, c, d, a])), 'reordered edges'
+assert same(poly([a, b, c, d, e, a]), poly([c, b, a, e, d, c])), 'ring start and winding'
+assert same(poly([a, b, c, d, a]), poly([[0, 1e-7], b, c, d, [0, 1e-7]])), 'tolerance'
+outer = [[0, 0], [9, 0], [9, 9], [0, 9], [0, 0]]
+one, two = [[1, 1], [2, 1], [2, 2], [1, 1]], [[5, 5], [6, 5], [6, 6], [5, 5]]
+assert same(poly(outer, one, two), poly(outer, two, one)), 'hole order'
+assert not same(poly(outer, one), poly(one, outer)), 'outer and inner roles swapped'
+assert same(multi(poly(one), poly(two)), multi(poly(two), poly(one))), 'part order'
+p, q, r, s, u, v = [0, 0], [1, 0], [0, 1], [5, 5], [6, 5], [5, 6]
+assert not same(multi(poly([p, q, r, p]), poly([s, u, v, s])),
+                multi(poly([p, q, s, p]), poly([r, u, v, r]))), 'vertices moved between parts'
+`,
+  );
+});
+
+test('Norway refresh keeps a still-tagged feature osmium did not export', (t) => {
+  python(
+    t,
+    String.raw`
+import json, runpy, sys
+merge = runpy.run_path(sys.argv[1])['merge']
+square = [[[10, 60], [10.01, 60], [10.01, 60.01], [10, 60.01], [10, 60]]]
+def line(osm_id, sequence):
+    return json.dumps({'id': osm_id, 'type': 'Feature', 'geometry': {'type': 'Polygon', 'coordinates': square},
+                       'properties': {'id': sequence, 'tags': {'building': 'data_center'},
+                                      'type': 'data_center', 'osm_id': osm_id}})
+norway = [([(0, 0), (20, 0), (20, 80), (0, 80)], False)]
+lines = [line(7, 1), line(8, 2)]
+out, report = merge(lines, {}, norway, {'w7'})
+assert out == [lines[0]], out
+assert report['unexported'] == ['w7'] and report['removed'] == ['w8'], report
+`,
+  );
+});
+
+test('Norway refresh lists tagged objects apart from the exported geometry', (t) => {
+  python(
+    t,
+    String.raw`
+import json, runpy, subprocess, sys, tempfile
+from pathlib import Path
+export = runpy.run_path(sys.argv[1])['export']
+tags = {'building': 'data_center'}
+ring = [[10, 60], [10.01, 60], [10.01, 60.01], [10, 60]]
+features = [
+    {'id': 'n1', 'properties': {'telecom': 'data_center'}, 'geometry': {'type': 'Point', 'coordinates': [10, 60]}},
+    {'id': 'w5', 'properties': tags, 'geometry': {'type': 'LineString', 'coordinates': ring}},
+    {'id': 'a10', 'properties': tags, 'geometry': {'type': 'MultiPolygon', 'coordinates': [[ring]]}},
+    {'id': 'w7', 'properties': tags, 'geometry': {'type': 'LineString', 'coordinates': ring[:3]}},
+]
+outputs = {
+    '.opl': 'n1 v1 Ttelecom=data_center x10 y60\nw5 v1 Tbuilding=data_center Nn2,n3,n4,n2\n'
+            'w7 v1 Tbuilding=data_center Nn2,n3,n4\nr9 v1 Ttelecom=data_center Mw8@outer\n',
+    '.geojsonseq': ''.join(chr(30) + json.dumps({'type': 'Feature', **f}) + '\n' for f in features),
+}
+def run(args, check=False):
+    target = Path(args[args.index('-o') + 1])
+    target.write_text(outputs.get(target.suffix, ''), encoding='utf-8')
+subprocess.run = run
+with tempfile.TemporaryDirectory() as cache:
+    fresh, tagged = export('osmium', Path(cache) / 'norway-test.osm.pbf', Path(cache), 'norway-test')
+assert sorted(fresh) == ['n1', 'w5'], fresh
+assert fresh['w5']['geometry'] == {'type': 'Polygon', 'coordinates': [ring]}, fresh['w5']
+assert tagged == {'n1', 'w5', 'w7', 'r9'}, tagged
+`,
+  );
+});

src/data/local_data/datacenters/README.md

@@ -27,7 +27,9 @@ reflects OSM as of the extract below, everything else the original snapshot.
   2026-10-05T20:21:35Z, MD5 `1d2cfdeb98980fce11b8891d0f9146c0`
 - Filter: `osmium tags-filter nwr/telecom=data_center nwr/building=data_center`
 - Contact tags are dropped as above; unchanged features keep their original
-  line, so geometry is only rewritten when tags or vertices actually changed.
+  line, so geometry is only rewritten when tags or rings actually changed.
+  A feature is removed only once it is no longer tagged; one still tagged but
+  without an exportable geometry keeps its line and is reported as unexported.
 - Refresh: `python3 scripts/build-datacenters-norway.py --cache <dir>` uses
   Geofabrik's current Norway extract and prints the dated name it used; record
   that name, its OSM timestamp and MD5 here. Requires `osmium-tool`.