Don't crash when parsing an empty polygon (#17)

maparoni · Nov 23, 2023 · 5e2c59a · 5e2c59a
1 parent d7cef4c
commit 5e2c59a
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diff --git a/Sources/GeoJSONKit/GeoJSON.swift b/Sources/GeoJSONKit/GeoJSON.swift
@@ -233,7 +233,7 @@ public struct GeoJSON: Hashable {
     private let precomputedHash: Int
 
     public init(_ rings: [[Position]]) {
-      self.exterior = LinearRing(positions: rings.first!)
+      self.exterior = LinearRing(positions: rings.first ?? [])
       self.interiors = rings
         .dropFirst()
         .map(LinearRing.init)

diff --git a/Tests/GeoJSONKitTests/GeoJSONParserTest.swift b/Tests/GeoJSONKitTests/GeoJSONParserTest.swift
@@ -171,6 +171,25 @@ final class GeoJSONParserTest: XCTestCase {
     XCTAssertNil(positions2[1].altitude)
   }
 
+  func testEmptyPolygon() throws {
+    let parsed = try GeoJSON(geoJSONString: """
+      {
+        "type": "Feature",
+        "properties": {
+          "stroke": "#F00",
+          "fill": "#F00",
+          "stroke-width": 6,
+          "fill-opacity": 0.1
+        },
+        "geometry": {
+          "type": "Polygon",
+          "coordinates": []
+        }
+      }
+      """)
+    XCTAssertNotNil(parsed)
+  }
+
   func testMultiPolygon() throws {
     let data = try XCTestCase.loadData(filename: "multipolygon")
     let parsed = try GeoJSON(data: data)