Merge branch 'development'

Author: groue

CHANGELOG.md

@@ -7,7 +7,7 @@ GRDB adheres to [Semantic Versioning](https://semver.org/), with one exception:
 
 #### 5.x Releases
 
-- `5.22.x` Releases - [5.22.0](#5220) | [5.22.1](#5221)
+- `5.22.x` Releases - [5.22.0](#5220) | [5.22.1](#5221) | [5.22.2](#5222)
 - `5.21.x` Releases - [5.21.0](#5210)
 - `5.20.x` Releases - [5.20.0](#5200)
 - `5.19.x` Releases - [5.19.0](#5190)
@@ -89,6 +89,12 @@ GRDB adheres to [Semantic Versioning](https://semver.org/), with one exception:
 
 ---
 
+## 5.22.2
+
+Released April 2, 2022 • [diff](https://github.com/groue/GRDB.swift/compare/v5.22.1...v5.22.2)
+
+- **Fixed** a 5.22.0 regression: [#1196](https://github.com/groue/GRDB.swift/pull/1196) by [@layoutSubviews](https://github.com/layoutSubviews): Fix a crash when an observation is quickly cancelled
+
 ## 5.22.1
 
 Released March 26, 2022 • [diff](https://github.com/groue/GRDB.swift/compare/v5.22.0...v5.22.1)

GRDB.swift.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name     = 'GRDB.swift'
-  s.version  = '5.22.1'
+  s.version  = '5.22.2'
 
   s.license  = { :type => 'MIT', :file => 'LICENSE' }
   s.summary  = 'A toolkit for SQLite databases, with a focus on application development.'

GRDB/ValueObservation/ValueConcurrentObserver.swift

@@ -192,7 +192,8 @@ extension ValueConcurrentObserver {
             (self.notificationCallbacks, self.databaseAccess)
         }
         guard let notificationCallbacks = notificationCallbacksOpt, let databaseAccess = databaseAccessOpt else {
-            // Likely a GRDB bug
+            // Likely a GRDB bug: during a synchronous start, user is not
+            // able to cancel observation.
             fatalError("can't start a cancelled or failed observation")
         }
 

GRDB/ValueObservation/ValueWriteOnlyObserver.swift

@@ -155,7 +155,8 @@ extension ValueWriteOnlyObserver {
             (self.notificationCallbacks, self.databaseAccess)
         }
         guard let notificationCallbacks = notificationCallbacksOpt, let writer = databaseAccessOpt?.writer else {
-            // Likely a GRDB bug
+            // Likely a GRDB bug: during a synchronous start, user is not
+            // able to cancel observation.
             fatalError("can't start a cancelled or failed observation")
         }
 
@@ -198,7 +199,11 @@ extension ValueWriteOnlyObserver {
         // from a database access.
         try writer.unsafeReentrantWrite { db in
             // Fetch & Start observing the database
-            let fetchedValue = try fetchAndStartObservation(db)
+            guard let fetchedValue = try fetchAndStartObservation(db) else {
+                // Likely a GRDB bug: during a synchronous start, user is not
+                // able to cancel observation.
+                fatalError("can't start a cancelled or failed observation")
+            }
 
             // Reduce
             return reduceQueue.sync {
@@ -218,12 +223,11 @@ extension ValueWriteOnlyObserver {
         // Start from a write access, so that self can register as a
         // transaction observer.
         writer.asyncWriteWithoutTransaction { db in
-            let isNotifying = self.lock.synchronized { self.notificationCallbacks != nil }
-            guard isNotifying else { return /* Cancelled */ }
-            
             do {
                 // Fetch & Start observing the database
-                let fetchedValue = try self.fetchAndStartObservation(db)
+                guard let fetchedValue = try self.fetchAndStartObservation(db) else {
+                    return /* Cancelled */
+                }
 
                 // Reduce
                 //
@@ -257,17 +261,19 @@ extension ValueWriteOnlyObserver {
 
     /// Fetches the initial value, and start observing the database.
     ///
+    /// Returns nil if the observation was cancelled before database observation
+    /// could start.
+    ///
     /// By grouping the initial fetch and the beginning of observation in a
     /// single database access, we are sure that no concurrent write can happen
     /// during the initial fetch, and that we won't miss any future change.
-    private func fetchAndStartObservation(_ db: Database) throws -> Reducer.Fetched {
+    private func fetchAndStartObservation(_ db: Database) throws -> Reducer.Fetched? {
         // TODO: [SR-214] remove -Opt suffix when we only support Xcode 12.5.1+
         let (eventsOpt, fetchOpt) = lock.synchronized {
             (notificationCallbacks?.events, databaseAccess?.fetch)
         }
         guard let events = eventsOpt, let fetch = fetchOpt else {
-            // Likely a GRDB bug
-            fatalError("can't start a cancelled or failed observation")
+            return nil /* Cancelled */
         }
 
         switch trackingMode {

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/v5.22.1 \
-	  --module-version 5.22.1 \
+	  --github-file-prefix https://github.com/groue/GRDB.swift/tree/v5.22.2 \
+	  --module-version 5.22.2 \
 	  --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 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)
+**Latest release**: April 2, 2022 • [version 5.22.2](https://github.com/groue/GRDB.swift/tree/v5.22.2) • [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+** | **v5.22.1**                                                 |
+| **Swift 5.3+** | **v5.22.2**                                                 |
 | 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>5.22.1</string>
+	<string>5.22.2</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>