From ca082cb6f4dcc3ff3765a848493fc215fb0be88e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Kita?= <lukasz.kita0@gmail.com>
Date: Mon, 13 Feb 2023 16:26:21 +0100
Subject: [PATCH] Bugfix pipeline call (#527)

* Make sure state of the pipeline is updated after handle_call
---
 lib/membrane/core/pipeline.ex                 | 15 +++++-----
 .../synchronous_pipeline_call_test.exs        | 30 +++++++++++++++++++
 2 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/lib/membrane/core/pipeline.ex b/lib/membrane/core/pipeline.ex
index 18f978416..004a73e31 100644
--- a/lib/membrane/core/pipeline.ex
+++ b/lib/membrane/core/pipeline.ex
@@ -146,13 +146,14 @@ defmodule Membrane.Core.Pipeline do
   def handle_call(message, from, state) do
     context = &CallbackContext.from_state(&1, from: from)
 
-    CallbackHandler.exec_and_handle_callback(
-      :handle_call,
-      Membrane.Core.Pipeline.ActionHandler,
-      %{context: context},
-      [message],
-      state
-    )
+    state =
+      CallbackHandler.exec_and_handle_callback(
+        :handle_call,
+        Membrane.Core.Pipeline.ActionHandler,
+        %{context: context},
+        [message],
+        state
+      )
 
     {:noreply, state}
   end
diff --git a/test/membrane/integration/synchronous_pipeline_call_test.exs b/test/membrane/integration/synchronous_pipeline_call_test.exs
index 332f486a7..28eb96f0c 100644
--- a/test/membrane/integration/synchronous_pipeline_call_test.exs
+++ b/test/membrane/integration/synchronous_pipeline_call_test.exs
@@ -1,6 +1,8 @@
 defmodule PipelineSynchronousCallTest do
   use ExUnit.Case, async: false
 
+  import Membrane.Testing.Assertions
+
   alias Membrane.Pipeline
 
   @msg "Some message"
@@ -46,4 +48,32 @@ defmodule PipelineSynchronousCallTest do
     reply = Pipeline.call(pid, {:instant_reply, @msg})
     assert reply == @msg
   end
+
+  defmodule PipelineSpawningChildrenOnCall do
+    use Membrane.Pipeline
+
+    @impl true
+    def handle_init(_ctx, _options) do
+      {[], %{}}
+    end
+
+    @impl true
+    def handle_call(:spawn_children, _ctx, state) do
+      spec =
+        child(:source, %Membrane.Testing.Source{output: [1, 2, 3]})
+        |> child(:sink, Membrane.Testing.Sink)
+
+      {[spec: spec, reply: nil], state}
+    end
+  end
+
+  test "Pipeline should be able to perform actions before replying on handle_call" do
+    {:ok, _supervisor, pipeline_pid} =
+      Membrane.Testing.Pipeline.start(module: PipelineSpawningChildrenOnCall)
+
+    Membrane.Pipeline.call(pipeline_pid, :spawn_children)
+    assert_pipeline_play(pipeline_pid)
+    assert_end_of_stream(pipeline_pid, :sink)
+    Pipeline.terminate(pipeline_pid, blocking?: true)
+  end
 end