Fixed an issue where jobs could run before their references are persisted

SessionUtilitiesKit/JobRunner/JobRunner.swift

@@ -138,13 +138,15 @@ public final class JobRunner {
             return
         }
         
-        queues.wrappedValue[updatedJob.variant]?.add(db, job: updatedJob, canStartJob: canStartJob)
-        
-        // Don't start the queue if the job can't be started
-        guard canStartJob else { return }
-        
-        // Start the job runner if needed
-        db.afterNextTransactionNestedOnce(dedupeId: "JobRunner-Start: \(updatedJob.variant)") { _ in
+        // Wait until the transaction has been completed before updating the queue (to ensure anything
+        // created during the transaction has been saved to the database before any corresponding jobs
+        // are run)
+        db.afterNextTransactionNested { _ in
+            queues.wrappedValue[updatedJob.variant]?.add(updatedJob, canStartJob: canStartJob)
+            
+            // Don't start the queue if the job can't be started
+            guard canStartJob else { return }
+            
             queues.wrappedValue[updatedJob.variant]?.start()
         }
     }
@@ -161,17 +163,22 @@ public final class JobRunner {
             return
         }
         
-        queues.wrappedValue[job.variant]?.upsert(db, job: job, canStartJob: canStartJob)
-        
-        // Don't start the queue if the job can't be started
-        guard canStartJob else { return }
-        
-        // Start the job runner if needed
-        db.afterNextTransactionNestedOnce(dedupeId: "JobRunner-Start: \(job.variant)") { _ in
+        // Wait until the transaction has been completed before updating the queue (to ensure anything
+        // created during the transaction has been saved to the database before any corresponding jobs
+        // are run)
+        db.afterNextTransactionNested { _ in
+            queues.wrappedValue[job.variant]?.upsert(job, canStartJob: canStartJob)
+            
+            // Don't start the queue if the job can't be started
+            guard canStartJob else { return }
+            
             queues.wrappedValue[job.variant]?.start()
         }
     }
     
+    /// Insert a job before another job in the queue
+    ///
+    /// **Note:** This function assumes the relevant job queue is already running and as such **will not** start the queue if it isn't running
     @discardableResult public static func insert(_ db: Database, job: Job?, before otherJob: Job) -> (Int64, Job)? {
         switch job?.behaviour {
             case .recurringOnActive, .recurringOnLaunch, .runOnceNextLaunch:
@@ -191,7 +198,12 @@ public final class JobRunner {
             return nil
         }
         
-        queues.wrappedValue[updatedJob.variant]?.insert(updatedJob, before: otherJob)
+        // Wait until the transaction has been completed before updating the queue (to ensure anything
+        // created during the transaction has been saved to the database before any corresponding jobs
+        // are run)
+        db.afterNextTransactionNested { _ in
+            queues.wrappedValue[updatedJob.variant]?.insert(updatedJob, before: otherJob)
+        }
         
         return (jobId, updatedJob)
     }
@@ -524,7 +536,7 @@ private final class JobQueue {
     
     // MARK: - Execution
     
-    fileprivate func add(_ db: Database, job: Job, canStartJob: Bool = true) {
+    fileprivate func add(_ job: Job, canStartJob: Bool = true) {
         // Check if the job should be added to the queue
         guard
             canStartJob,
@@ -541,11 +553,7 @@ private final class JobQueue {
         // If this is a concurrent queue then we should immediately start the next job
         guard executionType == .concurrent else { return }
         
-        // Ensure that the database commit has completed and then trigger the next job to run (need
-        // to ensure any interactions have been correctly inserted first)
-        db.afterNextTransactionNestedOnce(dedupeId: "JobRunner-Add: \(job.variant)") { [weak self] _ in
-            self?.runNextJob()
-        }
+        runNextJob()
     }
     
     /// Upsert a job onto the queue, if the queue isn't currently running and 'canStartJob' is true then this will start
@@ -553,7 +561,7 @@ private final class JobQueue {
     ///
     /// **Note:** If the job has a `behaviour` of `runOnceNextLaunch` or the `nextRunTimestamp`
     /// is in the future then the job won't be started
-    fileprivate func upsert(_ db: Database, job: Job, canStartJob: Bool = true) {
+    fileprivate func upsert(_ job: Job, canStartJob: Bool = true) {
         guard let jobId: Int64 = job.id else {
             SNLog("[JobRunner] Prevented attempt to upsert \(job.variant) job without id to queue")
             return
@@ -576,7 +584,7 @@ private final class JobQueue {
         // If we didn't update an existing job then we need to add it to the queue
         guard !didUpdateExistingJob else { return }
         
-        add(db, job: job, canStartJob: canStartJob)
+        add(job, canStartJob: canStartJob)
     }
     
     fileprivate func insert(_ job: Job, before otherJob: Job) {