Fixed ConcurrentModificationException and lazy not keeping cached value

square · Sep 11, 2024 · 38ce69d · 38ce69d
1 parent 7acf6f3
commit 38ce69d
Show file tree

Hide file tree

Showing 3 changed files with 38 additions and 2 deletions.
diff --git a/papa-main-trace/src/main/java/papa/MainThreadMessageScopedLazy.kt b/papa-main-trace/src/main/java/papa/MainThreadMessageScopedLazy.kt
@@ -11,6 +11,9 @@ class MainThreadMessageScopedLazy<T>(val provider: () -> T) : ReadOnlyProperty<A
     thisRef: Any?,
     property: KProperty<*>
   ): T {
+    valueOrNull?.let {
+      return it
+    }
     check(MainThreadMessageSpy.enabled) {
       "Can't use a MainThreadMessageScopedLazy when MainThreadMessageSpy is not enabled."
     }

diff --git a/papa-main-trace/src/main/java/papa/MainThreadMessageSpy.kt b/papa-main-trace/src/main/java/papa/MainThreadMessageSpy.kt
@@ -2,6 +2,7 @@ package papa
 
 import android.os.Build.VERSION
 import android.os.Looper
+import java.util.concurrent.CopyOnWriteArrayList
 
 object MainThreadMessageSpy {
 
@@ -12,7 +13,7 @@ object MainThreadMessageSpy {
     )
   }
 
-  private val tracers = mutableListOf<Tracer>()
+  private val tracers = CopyOnWriteArrayList<Tracer>()
 
   var enabled = false
     private set

diff --git a/papa/src/androidTest/java/papa/test/MainThreadMessageSpyTest.kt b/papa/src/androidTest/java/papa/test/MainThreadMessageSpyTest.kt
@@ -15,6 +15,7 @@ import papa.MainThreadMessageSpy.Tracer
 import papa.MainThreadTriggerStack
 import papa.internal.mainHandler
 import papa.internal.postAtFrontOfQueueAsync
+import papa.mainThreadMessageScopedLazy
 import papa.test.utilities.SkipTestIf
 import papa.test.utilities.TestActivity
 import papa.test.utilities.dismissCheckForUpdates
@@ -78,6 +79,14 @@ class MainThreadMessageSpyTest {
       .inOrder()
   }
 
+  @Test
+  fun no_ConcurrentModificationException_when_iterating_after_onCurrentMessageFinished_removes_its_tracer() {
+    runOnMainSync {
+      MainThreadMessageSpy.onCurrentMessageFinished {}
+      MainThreadMessageSpy.onCurrentMessageFinished {}
+    }
+  }
+
   @Test
   fun enabled_by_default() {
     val enabled = getOnMainSync {
@@ -200,4 +209,27 @@ class MainThreadMessageSpyTest {
     assertThat(inputCallbackFrameRenderedUptime).isEqualTo(inputTriggerFrameRenderedUptime)
     assertThat(isFrameRenderedInChoreographerFrame).isTrue()
   }
-}
+
+  @Test
+  fun mainThreadMessageScopedLazy_value_is_cached_for_same_message() {
+    val scopedLazy by mainThreadMessageScopedLazy { Any() }
+    val (msg1Read1, msg1Read2) = getOnMainSync {
+      scopedLazy to scopedLazy
+    }
+
+    assertThat(msg1Read1).isSameInstanceAs(msg1Read2)
+  }
+
+  @Test
+  fun mainThreadMessageScopedLazy_value_is_cleared_between_messages() {
+    val scopedLazy by mainThreadMessageScopedLazy { Any() }
+    val msg1Read = getOnMainSync {
+      scopedLazy
+    }
+    val msg2Read = getOnMainSync {
+      scopedLazy
+    }
+
+    assertThat(msg1Read).isNotSameInstanceAs(msg2Read)
+  }
+}