From f5594597755e4bda85ecc096106331a1c9f05c1e Mon Sep 17 00:00:00 2001
From: Christian Melchior <christian.melchior@mongodb.com>
Date: Wed, 11 Oct 2023 15:29:40 +0200
Subject: [PATCH] Fix network requests sometimes returning `null` instead of
 either returning success or failure

---
 CHANGELOG.md                                  |  1 +
 .../internal/network/NetworkRequestTests.kt   | 41 +++++++++++++++++++
 .../internal/network/NetworkRequest.java      | 16 +++-----
 .../internal/network/VoidNetworkRequest.java  |  2 +-
 4 files changed, 48 insertions(+), 12 deletions(-)
 create mode 100644 realm/realm-library/src/androidTestObjectServer/kotlin/io/realm/internal/network/NetworkRequestTests.kt

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 451a0ae2ec..e6b0bc0202 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 ### Fixed
 * Realm objects accessors behave as an unmanaged object after an incremental build. (Issue [#7844](https://github.com/realm/realm-java/pull/7844))
 * [RealmApp] Crash when opening a Realm with a proxy enabled. (Issue [#7828](https://github.com/realm/realm-java/issues/7828))
+* [RealmApp] It was possible to create a `User` object with invalid state that would throw a `NullPointerException` when accessed. (Issue [#7847](https://github.com/realm/realm-java/issues/7847))
 
 ### Compatibility
 * File format: Generates Realms with format v23. Unsynced Realms will be upgraded from Realm Java 2.0 and later. Synced Realms can only be read and upgraded if created with Realm Java v10.0.0-BETA.1.
diff --git a/realm/realm-library/src/androidTestObjectServer/kotlin/io/realm/internal/network/NetworkRequestTests.kt b/realm/realm-library/src/androidTestObjectServer/kotlin/io/realm/internal/network/NetworkRequestTests.kt
new file mode 100644
index 0000000000..422eb9a6ad
--- /dev/null
+++ b/realm/realm-library/src/androidTestObjectServer/kotlin/io/realm/internal/network/NetworkRequestTests.kt
@@ -0,0 +1,41 @@
+package io.realm.internal.network
+
+import androidx.test.platform.app.InstrumentationRegistry
+import io.realm.Realm
+import io.realm.mongodb.App
+import io.realm.mongodb.AppException
+import io.realm.mongodb.ErrorCode
+import junit.framework.TestCase.assertEquals
+import org.junit.Before
+import org.junit.Test
+import kotlin.test.assertFailsWith
+
+class NetworkRequestTests {
+
+	private lateinit var app: App
+
+	@Before
+	fun setUp() {
+		Realm.init(InstrumentationRegistry.getInstrumentation().targetContext)
+	}
+
+	// Test for https://github.com/realm/realm-java/issues/7847
+	@Test
+	fun interruptedRequestReturnsError() {
+		val request = object: NetworkRequest<Unit>() {
+			override fun mapSuccess(result: Any?): Unit {
+				Unit
+			}
+
+			override fun execute(callback: NetworkRequest<Unit>) {
+				Thread.currentThread().interrupt()
+			}
+		}
+		assertFailsWith<AppException> {
+			request.resultOrThrow()
+		}.also {
+			assertEquals(it.errorCode, ErrorCode.NETWORK_INTERRUPTED)
+			assertEquals(it.errorMessage, "Network request interrupted.")
+		}
+	}
+}
\ No newline at end of file
diff --git a/realm/realm-library/src/objectServer/java/io/realm/internal/network/NetworkRequest.java b/realm/realm-library/src/objectServer/java/io/realm/internal/network/NetworkRequest.java
index f877a004d9..88ec0876ab 100644
--- a/realm/realm-library/src/objectServer/java/io/realm/internal/network/NetworkRequest.java
+++ b/realm/realm-library/src/objectServer/java/io/realm/internal/network/NetworkRequest.java
@@ -48,9 +48,7 @@ public abstract class NetworkRequest<T> extends OsJavaNetworkTransport.NetworkTr
     @Override
     public void onSuccess(Object result) {
         T mappedResult = mapSuccess(result);
-        if (success != null) {
-            success.set(mappedResult);
-        }
+        success.set(mappedResult);
         latch.countDown();
     }
 
@@ -87,11 +85,11 @@ public T resultOrThrow() {
 
         execute(this);
         try {
-            // Wait indefinitely. Timeouts should be handled by the Network layer,
-            // so will eventually bubble up as an exception.
+            // Wait indefinitely. Timeouts should be handled by the Network layer, otherwise
+            // it can be interrupted manually by calling `RealmAsyncTask.cancel()`
             latch.await();
         } catch (InterruptedException e) {
-            RealmLog.debug("Network request interrupted.");
+            error.set(new AppException(ErrorCode.NETWORK_INTERRUPTED, "Network request interrupted."));
         }
 
         // Result of request should be available. Throw if an error happened, otherwise return
@@ -99,11 +97,7 @@ public T resultOrThrow() {
         if (error.get() != null) {
             throw error.get();
         } else {
-            if (success != null) {
-                return success.get();
-            } else {
-                return null;
-            }
+            return success.get();
         }
     }
 }
diff --git a/realm/realm-library/src/objectServer/java/io/realm/internal/network/VoidNetworkRequest.java b/realm/realm-library/src/objectServer/java/io/realm/internal/network/VoidNetworkRequest.java
index fb4bd9b5df..e86618f679 100644
--- a/realm/realm-library/src/objectServer/java/io/realm/internal/network/VoidNetworkRequest.java
+++ b/realm/realm-library/src/objectServer/java/io/realm/internal/network/VoidNetworkRequest.java
@@ -11,7 +11,7 @@
 
 /**
  * Specialized case of {@link NetworkRequest} where we are not interested in the response value,
- * just wether or not the request succeeded.
+ * just whether or not the request succeeded.
  */
 public abstract class VoidNetworkRequest extends NetworkRequest<Void> {