Merge branch 'development'

Author: groue

CHANGELOG.md

@@ -89,6 +89,12 @@ GRDB adheres to [Semantic Versioning](https://semver.org/), with one exception:
 
 ---
 
+## 5.22.1
+
+Released March 22, 2022 • [diff](https://github.com/groue/GRDB.swift/compare/v5.22.0...v5.22.1)
+
+- **Fixed** a 5.22.0 regression: [#1194](https://github.com/groue/GRDB.swift/issues/1194) ValueObservation could deadlock when the database is configured with a serial target DispatchQueue.
+
 ## 5.22.0
 
 Released March 22, 2022 • [diff](https://github.com/groue/GRDB.swift/compare/v5.21.0...v5.22.0)

GRDB.swift.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name     = 'GRDB.swift'
-  s.version  = '5.22.0'
+  s.version  = '5.22.1'
 
   s.license  = { :type => 'MIT', :file => 'LICENSE' }
   s.summary  = 'A toolkit for SQLite databases, with a focus on application development.'

GRDB/Core/Configuration.swift

@@ -316,4 +316,17 @@ public struct Configuration {
             return DispatchQueue(label: label, qos: qos)
         }
     }
+    
+    /// Creates a DispatchQueue which has the quality of service of
+    /// read accesses.
+    ///
+    /// The returned queue has no target queue, and won't create deadlocks when
+    /// used synchronously from a database access.
+    func makeDispatchQueue(label: String) -> DispatchQueue {
+        if let targetQueue = targetQueue {
+            return DispatchQueue(label: label, qos: targetQueue.qos)
+        } else {
+            return DispatchQueue(label: label, qos: qos)
+        }
+    }
 }

GRDB/ValueObservation/ValueConcurrentObserver.swift

@@ -138,7 +138,7 @@ final class ValueConcurrentObserver<Reducer: ValueReducer> {
             fetch: reducer._fetch)
         self.notificationCallbacks = NotificationCallbacks(events: events, onChange: onChange)
         self.reducer = reducer
-        self.reduceQueue = dbPool.configuration.makeReaderDispatchQueue(label: dbPool.configuration.identifier(
+        self.reduceQueue = dbPool.configuration.makeDispatchQueue(label: dbPool.configuration.identifier(
             defaultLabel: "GRDB",
             purpose: "ValueObservation"))
     }

GRDB/ValueObservation/ValueWriteOnlyObserver.swift

@@ -139,7 +139,7 @@ final class ValueWriteOnlyObserver<Writer: DatabaseWriter, Reducer: ValueReducer
             fetch: reducer._fetch)
         self.notificationCallbacks = NotificationCallbacks(events: events, onChange: onChange)
         self.reducer = reducer
-        self.reduceQueue = writer.configuration.makeReaderDispatchQueue(label: writer.configuration.identifier(
+        self.reduceQueue = writer.configuration.makeDispatchQueue(label: writer.configuration.identifier(
             defaultLabel: "GRDB",
             purpose: "ValueObservation"))
     }

Makefile

@@ -538,8 +538,8 @@ ifdef JAZZY
 	  --author 'Gwendal Roué' \
 	  --author_url https://github.com/groue \
 	  --github_url https://github.com/groue/GRDB.swift \
-	  --github-file-prefix https://github.com/groue/GRDB.swift/tree/v5.22.0 \
-	  --module-version 5.22.0 \
+	  --github-file-prefix https://github.com/groue/GRDB.swift/tree/v5.22.1 \
+	  --module-version 5.22.1 \
 	  --module GRDB \
 	  --root-url http://groue.github.io/GRDB.swift/docs/5.22/ \
 	  --output Documentation/Reference \

README.md

@@ -11,13 +11,13 @@
 
 ---
 
-**Latest release**: March 22, 2022 • [version 5.22.0](https://github.com/groue/GRDB.swift/tree/v5.22.0) • [CHANGELOG](CHANGELOG.md) • [Migrating From GRDB 4 to GRDB 5](Documentation/GRDB5MigrationGuide.md)
+**Latest release**: March 26, 2022 • [version 5.22.1](https://github.com/groue/GRDB.swift/tree/v5.22.1) • [CHANGELOG](CHANGELOG.md) • [Migrating From GRDB 4 to GRDB 5](Documentation/GRDB5MigrationGuide.md)
 
 **Requirements**: iOS 11.0+ / macOS 10.10+ / tvOS 9.0+ / watchOS 2.0+ • SQLite 3.8.5+ • Swift 5.3+ / Xcode 12+
 
 | Swift version  | GRDB version                                                |
 | -------------- | ----------------------------------------------------------- |
-| **Swift 5.3+** | **v5.22.0**                                                 |
+| **Swift 5.3+** | **v5.22.1**                                                 |
 | Swift 5.2      | [v5.12.0](https://github.com/groue/GRDB.swift/tree/v5.12.0) |
 | Swift 5.1      | [v4.14.0](https://github.com/groue/GRDB.swift/tree/v4.14.0) |
 | Swift 5        | [v4.14.0](https://github.com/groue/GRDB.swift/tree/v4.14.0) |

Support/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>5.22.0</string>
+	<string>5.22.1</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>

Tests/GRDBCombineTests/ValueObservationPublisherTests.swift

@@ -423,5 +423,53 @@ class ValueObservationPublisherTests : XCTestCase {
             .runAtTemporaryDatabasePath { try setUp(DatabaseQueue(path: $0)) }
             .runAtTemporaryDatabasePath { try setUp(DatabasePool(path: $0)) }
     }
+    
+    // MARK: - Regression Tests
+    
+    /// Regression test for https://github.com/groue/GRDB.swift/issues/1194
+    func testIssue1194() throws {
+        guard #available(OSX 10.15, iOS 13, tvOS 13, watchOS 6, *) else {
+            throw XCTSkip("Combine is not available")
+        }
+        
+        struct Record: Codable, FetchableRecord, PersistableRecord {
+            var id: Int64
+        }
+        
+        var configuration = Configuration()
+        configuration.targetQueue = DispatchQueue(label: "crash.test", qos: .userInitiated)
+        
+        let database = DatabaseQueue(configuration: configuration)
+        
+        var migrator = DatabaseMigrator()
+        migrator.registerMigration("v1") { (db) in
+            try db.create(table: Record.databaseTableName) { (t) in
+                t.autoIncrementedPrimaryKey("id")
+            }
+        }
+        
+        try migrator.migrate(database)
+        
+        let observation = ValueObservation.tracking { (db) in
+            try Record.fetchCount(db)
+        }
+        
+        let exp = expectation(description: "")
+        let cancellable = observation.publisher(in: database, scheduling: .immediate)
+            .map { _ in
+                database.readPublisher { (db) in
+                    try Record.fetchCount(db)
+                }
+            }
+            .switchToLatest()
+            .sink(receiveCompletion: { _ in },
+                  receiveValue: { (value) in
+                exp.fulfill()
+            })
+        
+        withExtendedLifetime(cancellable) {
+            waitForExpectations(timeout: 1)
+        }
+    }
 }
 #endif