Make FileStorage more opaque (#3010)

* Make `FileStorage` more opaque

Previously, we had a public protocol and conformances, but we don't
expect anyone to conform outside the library, so instead let's hide
things in a more opaque struct.

The downside of this PR is that it's a breaking API change pretty late
in the game:

```diff
-$0.defaultFileStorage = InMemoryFileStorage()
+$0.defaultFileStorage = .inMemory
```

We could add public deprecated functions that emulate the old
initializers if we think it's worth it...

* wip

* wip

* wip

* wip

* wip

* wip

* fix for 5.7.1

Author: stephencelis

Examples/SyncUps/SyncUps/App.swift

@@ -9,7 +9,7 @@ struct SyncUpsApp: App {
       ._printChanges()
   } withDependencies: {
     if ProcessInfo.processInfo.environment["UITesting"] == "true" {
-      $0.defaultFileStorage = InMemoryFileStorage()
+      $0.defaultFileStorage = .inMemory
     }
   }
 

Examples/SyncUps/SyncUpsTests/AppFeatureTests.swift

@@ -7,14 +7,12 @@ final class AppFeatureTests: XCTestCase {
   @MainActor
   func testDetailEdit() async throws {
     var syncUp = SyncUp.mock
-
-    let store = TestStore(
-      initialState: AppFeature.State(syncUpsList: SyncUpsList.State(syncUps: [syncUp]))
-    ) {
+    @Shared(.syncUps) var syncUps = [syncUp]
+    let store = TestStore(initialState: AppFeature.State()) {
       AppFeature()
     }
 
-    let sharedSyncUp = try XCTUnwrap(store.state.syncUpsList.$syncUps[id: syncUp.id])
+    let sharedSyncUp = try XCTUnwrap($syncUps[id: syncUp.id])
 
     await store.send(\.path.push, (id: 0, .detail(SyncUpDetail.State(syncUp: sharedSyncUp)))) {
       $0.path[id: 0] = .detail(SyncUpDetail.State(syncUp: sharedSyncUp))
@@ -41,15 +39,12 @@ final class AppFeatureTests: XCTestCase {
   @MainActor
   func testDelete() async throws {
     let syncUp = SyncUp.mock
-
-    let store = TestStore(
-      initialState: AppFeature.State(syncUpsList: SyncUpsList.State(syncUps: [syncUp]))
-    ) {
+    @Shared(.syncUps) var syncUps = [syncUp]
+    let store = TestStore(initialState: AppFeature.State()) {
       AppFeature()
     }
 
-    guard let sharedSyncUp = store.state.syncUpsList.$syncUps[id: syncUp.id]
-    else { return }
+    let sharedSyncUp = try XCTUnwrap($syncUps[id: syncUp.id])
 
     await store.send(\.path.push, (id: 0, .detail(SyncUpDetail.State(syncUp: sharedSyncUp)))) {
       $0.path[id: 0] = .detail(SyncUpDetail.State(syncUp: Shared(syncUp)))

Sources/ComposableArchitecture/Documentation.docc/Extensions/AppStorageKey.md

@@ -27,3 +27,4 @@
 ### Key-path access
 
 - ``PersistenceReaderKey/appStorage(_:)-5jsie``
+- ``AppStorageKeyPathKey``

Sources/ComposableArchitecture/Documentation.docc/Extensions/FileStorageKey.md

@@ -5,3 +5,7 @@
 ### Storing a value
 
 - ``PersistenceReaderKey/fileStorage(_:)``
+
+### Overriding storage
+
+- ``FileStorage``

Sources/ComposableArchitecture/Internal/Deprecations.swift

@@ -1,3 +1,13 @@
+// NB: Deprecated with 1.10.0:
+
+@available(*, deprecated, message: "Use '.fileSystem' ('FileStorage.fileSystem') instead")
+public func LiveFileStorage() -> FileStorage { .fileSystem }
+
+@available(*, deprecated, message: "Use '.inMemory' ('FileStorage.inMemory') instead")
+public func InMemoryFileStorage() -> FileStorage { .inMemory }
+
+// NB: Deprecated with 1.0.0:
+
 @available(*, unavailable, renamed: "Effect")
 public typealias EffectTask = Effect