[8.x] [RFC] PoC for making chained jobs batchable

src/Illuminate/Bus/Batch.php

@@ -164,7 +164,7 @@ public function add($jobs)
         $jobs->each->withBatchId($this->id);
 
         $this->repository->transaction(function () use ($jobs) {
-            $this->repository->incrementTotalJobs($this->id, count($jobs));
+            $this->repository->incrementTotalJobs($this->id, $this->countJobs($jobs));
 
             $this->queue->connection($this->options['connection'] ?? null)->bulk(
                 $jobs->all(),
@@ -427,4 +427,16 @@ public function jsonSerialize()
     {
         return $this->toArray();
     }
+
+    /**
+     * @param Collection $jobs
+     *
+     * @return int
+     */
+    private function countJobs(Collection $jobs)
+    {
+        return $jobs->reduce(function (int $count, $job) {
+            return $count + count($job->chained ?? []) + 1;
+        }, 0);
+    }
 }

src/Illuminate/Bus/Queueable.php

@@ -191,6 +191,10 @@ public function dispatchNextJobInChain()
     {
         if (! empty($this->chained)) {
             dispatch(tap(unserialize(array_shift($this->chained)), function ($next) {
+                if (property_exists($this, 'batchId') && method_exists($next, 'withBatchId')) {
+                    $next->withBatchId($this->batchId);
+                }
+
                 $next->chained = $this->chained;
 
                 $next->onConnection($next->connection ?: $this->chainConnection);

src/Illuminate/Foundation/Bus/PendingChain.php

@@ -114,6 +114,22 @@ public function catchCallbacks()
      * @return \Illuminate\Foundation\Bus\PendingDispatch
      */
     public function dispatch()
+    {
+        return app(Dispatcher::class)->dispatch($this->prepareFirstJob());
+    }
+
+    /**
+     * @return CallQueuedClosure
+     */
+    public function dispatchInBatch()
+    {
+        return $this->prepareFirstJob();
+    }
+
+    /**
+     * @return CallQueuedClosure|mixed
+     */
+    public function prepareFirstJob()
     {
         if (is_string($this->job)) {
             $firstJob = new $this->job(...func_get_args());
@@ -128,6 +144,6 @@ public function dispatch()
         $firstJob->chain($this->chain);
         $firstJob->chainCatchCallbacks = $this->catchCallbacks();
 
-        return app(Dispatcher::class)->dispatch($firstJob);
+        return $firstJob;
     }
 }