use Int64 for date math, fixes vapor#53

Author: tanner0101

Sources/PostgreSQL/Data/PostgreSQLData+Date.swift

@@ -18,7 +18,7 @@ extension Date: PostgreSQLDataConvertible {
             case .time, .timetz: throw PostgreSQLError.decode(Date.self, from: data)
             case .date:
                 let days = value.as(Int32.self, default: 0).bigEndian
-                let seconds = days * _secondsInDay
+                let seconds = Int64(days) * _secondsInDay
                 return Date(timeInterval: Double(seconds), since: _psqlDateStart)
             default: throw PostgreSQLError.decode(Date.self, from: data)
             }
@@ -35,7 +35,7 @@ extension Date: PostgreSQLDataConvertible {
 // MARK: Private
 
 private let _microsecondsPerSecond: Int64 = 1_000_000
-private let _secondsInDay: Int32 = 24 * 60 * 60
+private let _secondsInDay: Int64 = 24 * 60 * 60
 private let _psqlDateStart = Date(timeIntervalSince1970: 946_684_800) // values are stored as seconds before or after midnight 2000-01-01
 
 private extension String {

Tests/PostgreSQLTests/PostgreSQLConnectionTests.swift

@@ -546,6 +546,28 @@ class PostgreSQLConnectionTests: XCTestCase {
             .run(decoding: Planet.self).wait()
         XCTAssertNotEqual(planetsA, planetsB)
     }
+    
+    // https://github.com/vapor/postgresql/issues/53
+    func testInvalidDate() throws {
+        let conn = try PostgreSQLConnection.makeTest(transport: .cleartext)
+        _ = try conn.simpleQuery(.createTable(.init(
+            name: "timetest",
+            columns: [.column("date", .date)]
+        ))).wait()
+        defer { _ = try? conn.simpleQuery(.drop(table: "timetest")).wait() }
+        
+        struct Time: PostgreSQLTable, Equatable {
+            static let postgreSQLTable = "timetest"
+            var date: Date
+        }
+        
+        _ = try conn.simpleQuery(.raw(query: "INSERT INTO timetest (date) VALUES ('0214-02-05')", binds: [])).wait()
+        let fetch: [Time] = try conn.select().all().from(Time.self).run(decoding: Time.self).wait()
+        switch fetch.count {
+        case 1: XCTAssertEqual(fetch[0].date.timeIntervalSince1970, -55410998400)
+        default: XCTFail("invalid row count")
+        }
+    }
 
     static var allTests = [
         ("testVersion", testVersion),
@@ -566,6 +588,7 @@ class PostgreSQLConnectionTests: XCTestCase {
         ("testListen", testListen),
         ("testSum", testSum),
         ("testOrderBy", testOrderBy),
+        ("testInvalidDate", testInvalidDate),
     ]
 }