Preliminary work for GRDB7

There remains a warning in DatabaseRegionObservation+Rx.swift.

See #72

Author: groue

Package.swift

@@ -5,16 +5,16 @@ import PackageDescription
 let package = Package(
     name: "RxGRDB",
     platforms: [
-        .iOS(.v11),
-        .macOS(.v10_13),
-        .tvOS(.v11),
-        .watchOS(.v4),
+        .iOS(.v13),
+        .macOS(.v10_15),
+        .tvOS(.v13),
+        .watchOS(.v7),
     ],
     products: [
         .library(name: "RxGRDB", targets: ["RxGRDB"]),
     ],
     dependencies: [
-        .package(url: "https://github.com/groue/GRDB.swift.git", .upToNextMajor(from: "6.0.0")),
+        .package(url: "https://github.com/groue/GRDB.swift.git", .upToNextMajor(from: "7.0.0")),
         .package(url: "https://github.com/ReactiveX/RxSwift.git", .upToNextMajor(from: "6.0.0"))
     ],
     targets: [

Sources/RxGRDB/DatabaseWriter+Rx.swift

@@ -32,7 +32,7 @@ extension Reactive where Base: DatabaseWriter {
     /// - parameter updates: A closure which writes in the database.
     public func write<T>(
         observeOn scheduler: ImmediateSchedulerType = MainScheduler.instance,
-        updates: @escaping (Database) throws -> T)
+        updates: @escaping @Sendable (Database) throws -> T)
     -> Single<T>
     {
         Single
@@ -67,8 +67,8 @@ extension Reactive where Base: DatabaseWriter {
     /// - parameter value: A closure which reads from the database.
     public func write<T, U>(
         observeOn scheduler: ImmediateSchedulerType = MainScheduler.instance,
-        updates: @escaping (Database) throws -> T,
-        thenRead value: @escaping (Database, T) throws -> U)
+        updates: @escaping @Sendable (Database) throws -> T,
+        thenRead value: @escaping @Sendable (Database, T) throws -> U)
     -> Single<U>
     {
         Single
@@ -84,9 +84,12 @@ extension Reactive where Base: DatabaseWriter {
                         observer(.failure(error))
                         return
                     }
+                    
+                    // Non-mutable copy so that compiler does not raise any warning.
+                    let updatesValue2 = updatesValue
                     self.base.spawnConcurrentRead { dbResult in
                         do {
-                            try observer(.success(value(dbResult.get(), updatesValue!)))
+                            try observer(.success(value(dbResult.get(), updatesValue2!)))
                         } catch {
                             observer(.failure(error))
                         }

Sources/RxGRDB/ValueObservation+Rx.swift

@@ -1,3 +1,4 @@
+import Dispatch
 import GRDB
 import RxSwift