From 20cda451293ecbf7d2d6fdafb8687349f5fd9591 Mon Sep 17 00:00:00 2001
From: Aditya Sharat <adityasharat@meta.com>
Date: Thu, 21 Mar 2024 15:22:34 -0700
Subject: [PATCH] Fixes bug in TraceListener implementation

Summary: Fixes bug in TraceListener implementation

Reviewed By: fabiocarballo

Differential Revision: D55187241

fbshipit-source-id: 7698360b486b524e8678b2089136ee630d2b4adc
---
 .../facebook/rendercore/debug/DebugEvents.kt  |  2 +-
 .../rendercore/debug/DebugEventsTest.kt       | 23 ++++++++++++++++++-
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/litho-rendercore/src/main/java/com/facebook/rendercore/debug/DebugEvents.kt b/litho-rendercore/src/main/java/com/facebook/rendercore/debug/DebugEvents.kt
index 9e7de03ab9b..9a42c87678b 100644
--- a/litho-rendercore/src/main/java/com/facebook/rendercore/debug/DebugEvents.kt
+++ b/litho-rendercore/src/main/java/com/facebook/rendercore/debug/DebugEvents.kt
@@ -362,7 +362,7 @@ object DebugEventDispatcher {
     val subscribersToNotify =
         subscribers.filter { subscriber ->
           val matches = subscriber.events.contains(type) || subscriber.events.contains(All)
-          if (subscriber is TraceListener<*>) {
+          if (matches && subscriber is TraceListener<*>) {
             traceListeners.add(subscriber as TraceListener<Any?>)
           }
           return@filter matches
diff --git a/litho-rendercore/src/test/java/com/facebook/rendercore/debug/DebugEventsTest.kt b/litho-rendercore/src/test/java/com/facebook/rendercore/debug/DebugEventsTest.kt
index 5d7326bf7d7..64a39e5cb21 100644
--- a/litho-rendercore/src/test/java/com/facebook/rendercore/debug/DebugEventsTest.kt
+++ b/litho-rendercore/src/test/java/com/facebook/rendercore/debug/DebugEventsTest.kt
@@ -422,11 +422,15 @@ class DebugEventsTest {
 
   @Test
   fun `trace event should be dispatched to trace listeners`() {
+    val traceListener0 = TestTraceListener("random")
+    DebugEventBus.subscribe(traceListener0)
+
     val traceListener1 = TestTraceListener()
     DebugEventBus.subscribe(traceListener1)
 
     DebugEventDispatcher.trace(type = TestEvent, renderStateId = { TestRenderStateId }) {}
 
+    assertThat(traceListener0.records.size).isEqualTo(0)
     assertThat(traceListener1.records.size).isEqualTo(1)
 
     val traceListener2 = TestTraceListener()
@@ -434,8 +438,23 @@ class DebugEventsTest {
 
     DebugEventDispatcher.trace(type = TestEvent, renderStateId = { TestRenderStateId }) {}
 
+    assertThat(traceListener0.records.size).isEqualTo(0)
     assertThat(traceListener1.records.size).isEqualTo(2)
     assertThat(traceListener2.records.size).isEqualTo(1)
+
+    DebugEventBus.unsubscribe(traceListener1)
+
+    DebugEventDispatcher.trace(type = TestEvent, renderStateId = { TestRenderStateId }) {}
+
+    assertThat(traceListener0.records.size).isEqualTo(0)
+    assertThat(traceListener1.records.size).isEqualTo(2)
+    assertThat(traceListener2.records.size).isEqualTo(2)
+
+    DebugEventDispatcher.trace(type = "random", renderStateId = { TestRenderStateId }) {}
+
+    assertThat(traceListener0.records.size).isEqualTo(1)
+    assertThat(traceListener1.records.size).isEqualTo(2)
+    assertThat(traceListener2.records.size).isEqualTo(2)
   }
 
   class TestEventSubscriber(val listener: (DebugEvent) -> Unit) : DebugEventSubscriber(TestEvent) {
@@ -453,7 +472,9 @@ class DebugEventsTest {
     }
   }
 
-  class TestTraceListener : TraceListener<Int>, DebugEventSubscriber(TestEvent) {
+  class TestTraceListener(
+      vararg events: String = arrayOf(TestEvent),
+  ) : TraceListener<Int>, DebugEventSubscriber(*events) {
 
     val records = mutableListOf<Any>()