LogErrorFunction is Sendable

GRDB/Core/Database.swift

@@ -122,8 +122,14 @@ let SQLITE_TRANSIENT = unsafeBitCast(OpaquePointer(bitPattern: -1), to: sqlite3_
 /// - ``logError``
 /// - ``releaseMemory()``
 /// - ``trace(options:_:)``
+///
+/// ### Supporting Types
+///
+/// - ``BusyCallback``
+/// - ``BusyMode``
 /// - ``CheckpointMode``
 /// - ``DatabaseBackupProgress``
+/// - ``LogErrorFunction``
 /// - ``StorageClass``
 /// - ``TraceEvent``
 /// - ``TracingOptions``
@@ -143,8 +149,26 @@ public final class Database: CustomStringConvertible, CustomDebugStringConvertib
 
     /// The error logging function.
     ///
+    /// SQLite can be configured to invoke a callback function containing
+    /// an error code and a terse error message whenever anomalies occur.
+    ///
+    /// This global error callback must be configured early in the lifetime
+    /// of your application:
+    ///
+    /// ```swift
+    /// Database.logError = { (resultCode, message) in
+    ///     NSLog("%@", "SQLite error \(resultCode): \(message)")
+    /// }
+    /// ```
+    ///
+    /// - warning: Database.logError must be set before any database
+    ///   connection is opened. This includes the connections that your
+    ///   application opens with GRDB, but also connections opened by
+    ///   other tools, such as third-party libraries. Setting it after a
+    ///   connection has been opened is an SQLite misuse, and has no effect.
+    ///
     /// Related SQLite documentation: <https://www.sqlite.org/errlog.html>
-    public static var logError: LogErrorFunction? = nil {
+    nonisolated(unsafe) public static var logError: LogErrorFunction? = nil {
         didSet {
             if logError != nil {
                 _registerErrorLogCallback { (_, code, message) in
@@ -1830,7 +1854,7 @@ extension Database {
 
     // MARK: - Database-Related Types
 
-    /// See BusyMode and <https://www.sqlite.org/c3ref/busy_handler.html>
+    /// See ``BusyMode`` and <https://www.sqlite.org/c3ref/busy_handler.html>
     public typealias BusyCallback = @Sendable (_ numberOfTries: Int) -> Bool
 
     /// When there are several connections to a database, a connection may try
@@ -2019,7 +2043,7 @@ extension Database {
     }
 
     /// An error log function that takes an error code and message.
-    public typealias LogErrorFunction = (_ resultCode: ResultCode, _ message: String) -> Void
+    public typealias LogErrorFunction = @Sendable (_ resultCode: ResultCode, _ message: String) -> Void
 
     /// An SQLite storage class.
     ///

TODO.md

@@ -109,7 +109,7 @@
 - [X] GRDB7: Sendable: RowAdapter (d138af26)
 - [ ] GRDB7: Sendable: ValueObservationScheduler (8429eb68)
 - [X] GRDB7: Sendable: DatabaseCollation (4d9d67dd)
-- [ ] GRDB7: Sendable: LogErrorFunction (f362518d)
+- [X] GRDB7: Sendable: LogErrorFunction (f362518d)
 - [ ] GRDB7: Sendable: ReadWriteBox (57a86a0e)
 - [ ] GRDB7: Sendable: Pool (f13b2d2e)
 - [ ] GRDB7: Sendable: OnDemandFuture fulfill (2aabc4c1)

Tests/GRDBTests/DatabasePoolTests.swift

@@ -397,7 +397,7 @@ class DatabasePoolTests: GRDBTestCase {
                 XCTFail("Expected Error")
             } catch DatabaseError.SQLITE_BUSY { }
         }
-        XCTAssert(lastMessage!.contains("unfinalized statement: SELECT * FROM sqlite_master"))
+        XCTAssert(lastSQLiteDiagnostic!.message.contains("unfinalized statement: SELECT * FROM sqlite_master"))
 
         // Database is not closed: no error
         try dbPool.write { db in
@@ -427,7 +427,7 @@ class DatabasePoolTests: GRDBTestCase {
         //
         // The first comes from GRDB, and the second, depending on the SQLite
         // version, from `sqlite3_close_v2()`. Write the test so that it always pass:
-        XCTAssert(lastMessage!.contains("unfinalized statement"))
+        XCTAssert(lastSQLiteDiagnostic!.message.contains("unfinalized statement"))
 
         // Database is in a zombie state.
         // In the zombie state, access throws SQLITE_MISUSE

Tests/GRDBTests/DatabaseQueueTests.swift

@@ -458,7 +458,7 @@ class DatabaseQueueTests: GRDBTestCase {
                 XCTFail("Expected Error")
             } catch DatabaseError.SQLITE_BUSY { }
         }
-        XCTAssert(lastMessage!.contains("unfinalized statement: SELECT * FROM sqlite_master"))
+        XCTAssert(lastSQLiteDiagnostic!.message.contains("unfinalized statement: SELECT * FROM sqlite_master"))
 
         // Database is not closed: no error
         try dbQueue.inDatabase { db in

Tests/GRDBTests/DatabaseSnapshotTests.swift

@@ -424,7 +424,7 @@ class DatabaseSnapshotTests: GRDBTestCase {
                 XCTFail("Expected Error")
             } catch DatabaseError.SQLITE_BUSY { }
         }
-        XCTAssert(lastMessage!.contains("unfinalized statement: SELECT * FROM sqlite_master"))
+        XCTAssert(lastSQLiteDiagnostic!.message.contains("unfinalized statement: SELECT * FROM sqlite_master"))
 
         // Database is not closed: no error
         try snapshot.read { db in

Tests/GRDBTests/GRDBTestCase.swift

@@ -12,15 +12,15 @@ import XCTest
 @testable import GRDB
 
 // Support for Database.logError
-var lastResultCode: ResultCode? = nil
-var lastMessage: String? = nil
+struct SQLiteDiagnostic {
+    var resultCode: ResultCode
+    var message: String
+}
+private let lastSQLiteDiagnosticMutex = Mutex<SQLiteDiagnostic?>(nil)
+var lastSQLiteDiagnostic: SQLiteDiagnostic? { lastSQLiteDiagnosticMutex.load() }
 let logErrorSetup: Void = {
-    let lock = NSLock()
     Database.logError = { (resultCode, message) in
-        lock.lock()
-        defer { lock.unlock() }
-        lastResultCode = resultCode
-        lastMessage = message
+        lastSQLiteDiagnosticMutex.store(SQLiteDiagnostic(resultCode: resultCode, message: message))
     }
 }()