[google_maps_flutter]: LatLng longitude loses precision in constructor #90574 (#4374)

Author: Murray-Meller

packages/google_maps_flutter/google_maps_flutter_platform_interface/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 2.1.3
+
+* `LatLng` constructor maintains longitude precision when given within
+  acceptable range
+
 ## 2.1.2
 
 * Add additional marker drag events

packages/google_maps_flutter/google_maps_flutter_platform_interface/lib/src/types/location.dart

@@ -14,13 +14,16 @@ class LatLng {
   /// The latitude is clamped to the inclusive interval from -90.0 to +90.0.
   ///
   /// The longitude is normalized to the half-open interval from -180.0
-  /// (inclusive) to +180.0 (exclusive)
+  /// (inclusive) to +180.0 (exclusive).
   const LatLng(double latitude, double longitude)
       : assert(latitude != null),
         assert(longitude != null),
         latitude =
             (latitude < -90.0 ? -90.0 : (90.0 < latitude ? 90.0 : latitude)),
-        longitude = (longitude + 180.0) % 360.0 - 180.0;
+        // Avoids normalization if possible to prevent unnecessary loss of precision
+        longitude = longitude >= -180 && longitude < 180
+            ? longitude
+            : (longitude + 180.0) % 360.0 - 180.0;
 
   /// The latitude in degrees between -90.0 and 90.0, both inclusive.
   final double latitude;

packages/google_maps_flutter/google_maps_flutter_platform_interface/pubspec.yaml

@@ -4,7 +4,7 @@ repository: https://github.com/flutter/plugins/tree/master/packages/google_maps_
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+maps%22
 # NOTE: We strongly prefer non-breaking changes, even at the expense of a
 # less-clean API. See https://flutter.dev/go/platform-interface-breaking-changes
-version: 2.1.2
+version: 2.1.3
 
 environment:
   sdk: '>=2.12.0 <3.0.0'

packages/google_maps_flutter/google_maps_flutter_platform_interface/test/types/location_test.dart

@@ -0,0 +1,62 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:google_maps_flutter_platform_interface/google_maps_flutter_platform_interface.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  group('LanLng constructor', () {
+    test('Maintains longitude precision if within acceptable range', () async {
+      const lat = -34.509981;
+      const lng = 150.792384;
+
+      final latLng = LatLng(lat, lng);
+
+      expect(latLng.latitude, equals(lat));
+      expect(latLng.longitude, equals(lng));
+    });
+
+    test('Normalizes longitude that is below lower limit', () async {
+      const lat = -34.509981;
+      const lng = -270.0;
+
+      final latLng = LatLng(lat, lng);
+
+      expect(latLng.latitude, equals(lat));
+      expect(latLng.longitude, equals(90.0));
+    });
+
+    test('Normalizes longitude that is above upper limit', () async {
+      const lat = -34.509981;
+      const lng = 270.0;
+
+      final latLng = LatLng(lat, lng);
+
+      expect(latLng.latitude, equals(lat));
+      expect(latLng.longitude, equals(-90.0));
+    });
+
+    test('Includes longitude set to lower limit', () async {
+      const lat = -34.509981;
+      const lng = -180.0;
+
+      final latLng = LatLng(lat, lng);
+
+      expect(latLng.latitude, equals(lat));
+      expect(latLng.longitude, equals(-180.0));
+    });
+
+    test('Normalizes longitude set to upper limit', () async {
+      const lat = -34.509981;
+      const lng = 180.0;
+
+      final latLng = LatLng(lat, lng);
+
+      expect(latLng.latitude, equals(lat));
+      expect(latLng.longitude, equals(-180.0));
+    });
+  });
+}