From 3d80b1b3aac1b94bd4319a7a550942bd3e21f971 Mon Sep 17 00:00:00 2001
From: Lukas Kubanek <lukas.kubanek@me.com>
Date: Fri, 24 Jul 2026 10:44:34 +0200
Subject: [PATCH] Fix in-memory metadatabase creation in defaultMetadatabase

---
 .../CloudKit/Internal/Metadatabase.swift      |  7 ++++-
 .../CloudKitTests/MetadatabaseTests.swift     | 26 +++++++++++++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)
 create mode 100644 Tests/SQLiteDataTests/CloudKitTests/MetadatabaseTests.swift

diff --git a/Sources/SQLiteData/CloudKit/Internal/Metadatabase.swift b/Sources/SQLiteData/CloudKit/Internal/Metadatabase.swift
index d6638f63..92ca054d 100644
--- a/Sources/SQLiteData/CloudKit/Internal/Metadatabase.swift
+++ b/Sources/SQLiteData/CloudKit/Internal/Metadatabase.swift
@@ -24,7 +24,12 @@
       throw InMemoryDatabase()
     }
 
-    let metadatabase = try DatabasePool(path: url.path(percentEncoded: false))
+    let metadatabase: any DatabaseWriter =
+      if url.isInMemory {
+        try DatabaseQueue(path: url.absoluteString)
+      } else {
+        try DatabasePool(path: url.path(percentEncoded: false))
+      }
     try migrate(metadatabase: metadatabase)
     return metadatabase
   }
diff --git a/Tests/SQLiteDataTests/CloudKitTests/MetadatabaseTests.swift b/Tests/SQLiteDataTests/CloudKitTests/MetadatabaseTests.swift
new file mode 100644
index 00000000..8657d2a9
--- /dev/null
+++ b/Tests/SQLiteDataTests/CloudKitTests/MetadatabaseTests.swift
@@ -0,0 +1,26 @@
+#if canImport(CloudKit)
+  import Foundation
+  import GRDB
+  import OSLog
+  @testable import SQLiteData
+  import Testing
+
+  @Suite struct MetadatabaseTests {
+    @available(iOS 17, macOS 14, tvOS 17, watchOS 10, *)
+    @Test func inMemoryMetadatabase() throws {
+      let url = try URL.metadatabase(databasePath: ":memory:", containerIdentifier: nil)
+      #expect(url.isInMemory)
+
+      let metadatabase = try defaultMetadatabase(
+        logger: Logger(subsystem: "test", category: "test"),
+        url: url
+      )
+      let mainDatabaseFile = try metadatabase.read { db in
+        try String.fetchOne(db, sql: "SELECT file FROM pragma_database_list WHERE name = 'main'")
+      }
+      // NB: SQLite reports an empty file path for in-memory databases. A non-empty path
+      //     means the metadatabase was silently created on disk.
+      #expect(mainDatabaseFile == "")
+    }
+  }
+#endif