Set up dispatch sources after external write. (#148)

* Set up dispatch sources after external write.

* fix

* fix

Author: mbrandonw

Sources/Sharing/SharedKeys/FileStorageKey.swift

@@ -150,11 +150,7 @@
               [weak self] in
               guard let self else { return }
               let fileExists = self.storage.fileExists(self.url)
-              defer {
-                if !fileExists {
-                  setUpSources()
-                }
-              }
+              defer { setUpSources() }
               let modificationDate =
                 fileExists
                 ? (try? self.storage.attributesOfItemAtPath(self.url.path)[.modificationDate]

Tests/SharingTests/FileStorageTests.swift

@@ -421,6 +421,50 @@
         #expect(count == 1)
         #expect(try String(decoding: Data(contentsOf: .fileURL), as: UTF8.self) == "1")
       }
+
+      @Test func twoShareds() async throws {
+        let count1URL = URL(fileURLWithPath: NSTemporaryDirectory())
+          .appendingPathComponent("file.json")
+        let count2URL = URL(fileURLWithPath: NSTemporaryDirectory() + "/")
+          .appendingPathComponent("file.json")
+        try? FileManager.default.removeItem(at: count1URL)
+        try? FileManager.default.removeItem(at: count2URL)
+
+        @Shared(.fileStorage(count1URL)) var count1 = 0
+        @Shared(.fileStorage(count2URL)) var count2 = 0
+
+        $count1.withLock { $0 = 42 }
+        #expect(count1 == 42)
+        try await Task.sleep(for: .seconds(1.5))
+        #expect(count2 == 42)
+
+        $count2.withLock { $0 = 1728 }
+        #expect(count2 == 1728)
+        try await Task.sleep(for: .seconds(1.5))
+        #expect(count1 == 1728)
+
+        $count1.withLock { $0 = 999 }
+        #expect(count1 == 999)
+        try await Task.sleep(for: .seconds(1.5))
+        #expect(count2 == 999)
+      }
+
+      @Test func externalAtomicWrite() async throws {
+        @Shared(.fileStorage(.fileURL)) var count = 0
+
+        try Data("42".utf8).write(to: .fileURL, options: .atomic)
+        try await Task.sleep(for: .seconds(1.5))
+        #expect(count == 42)
+
+        try Data("1728".utf8).write(to: .fileURL, options: .atomic)
+        try await Task.sleep(for: .seconds(1.5))
+        #expect(count == 1728)
+
+        $count.withLock { $0 = 999 }
+        try await Task.sleep(for: .seconds(1.5))
+        #expect(count == 999)
+        #expect(try String(decoding: Data(contentsOf: .fileURL), as: UTF8.self) == "999")
+      }
     }
   }