From 4363566599d4c2cc37582f9a1237945f24dbcdc9 Mon Sep 17 00:00:00 2001
From: Zach Klippenstein <zachklipp@squareup.com>
Date: Tue, 28 Jul 2020 10:01:04 -0700
Subject: [PATCH] Revert "Emit output before next render pass."

This reverts commit b084b16cf72618702e442e8ceac99cf168debbcd from #68 and closes #147.
The change this reverts was related to issue #54.
---
 .../src/main/java/com/squareup/workflow1/RenderWorkflow.kt  | 6 ++++--
 .../java/com/squareup/workflow1/RenderWorkflowInTest.kt     | 4 ++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/workflow-runtime/src/main/java/com/squareup/workflow1/RenderWorkflow.kt b/workflow-runtime/src/main/java/com/squareup/workflow1/RenderWorkflow.kt
index 8f399a250..86f4fee5a 100644
--- a/workflow-runtime/src/main/java/com/squareup/workflow1/RenderWorkflow.kt
+++ b/workflow-runtime/src/main/java/com/squareup/workflow1/RenderWorkflow.kt
@@ -151,10 +151,12 @@ fun <PropsT, OutputT, RenderingT> renderWorkflowIn(
       // It might look weird to start by consuming the output before getting the rendering below,
       // but remember the first render pass already occurred above, before this coroutine was even
       // launched.
-      runner.nextOutput()
-          ?.let { onOutput(it.value) }
+      val output = runner.nextOutput()
 
+      // After receiving an output, the next render pass must be done before emitting that output,
+      // so that the workflow states appear consistent to observers of the outputs and renderings.
       renderingsAndSnapshots.value = runner.nextRendering()
+      output?.let { onOutput(it.value) }
     }
   }
 
diff --git a/workflow-runtime/src/test/java/com/squareup/workflow1/RenderWorkflowInTest.kt b/workflow-runtime/src/test/java/com/squareup/workflow1/RenderWorkflowInTest.kt
index 93a83c776..012b66eed 100644
--- a/workflow-runtime/src/test/java/com/squareup/workflow1/RenderWorkflowInTest.kt
+++ b/workflow-runtime/src/test/java/com/squareup/workflow1/RenderWorkflowInTest.kt
@@ -439,8 +439,8 @@ class RenderWorkflowInTest {
     assertEquals(
         listOf(
             "rendering({no output})",
-            "output(output)",
-            "rendering(output)"
+            "rendering(output)",
+            "output(output)"
         ),
         events
     )