Kotlinify SoftAssertions (#43911)

Summary:
Pull Request resolved: #43911

Changelog: [Internal]

As part of the Sustainability Week (see [post](https://fb.workplace.com/groups/251759413609061/permalink/742797531171911/)).

Reviewed By: tdn120

Differential Revision: D55797031

fbshipit-source-id: eb53ae671b0a7b5d277b931a11eb0fcd84c51a19

packages/react-native/ReactAndroid/api/ReactAndroid.api

@@ -1466,11 +1466,11 @@ public class com/facebook/react/bridge/RuntimeScheduler {
 	public fun <init> (Lcom/facebook/jni/HybridData;)V
 }
 
-public class com/facebook/react/bridge/SoftAssertions {
-	public fun <init> ()V
-	public static fun assertCondition (ZLjava/lang/String;)V
-	public static fun assertNotNull (Ljava/lang/Object;)Ljava/lang/Object;
-	public static fun assertUnreachable (Ljava/lang/String;)V
+public final class com/facebook/react/bridge/SoftAssertions {
+	public static final field INSTANCE Lcom/facebook/react/bridge/SoftAssertions;
+	public static final fun assertCondition (ZLjava/lang/String;)V
+	public static final fun assertNotNull (Ljava/lang/Object;)Ljava/lang/Object;
+	public static final fun assertUnreachable (Ljava/lang/String;)V
 }
 
 public abstract interface class com/facebook/react/bridge/Systrace : com/facebook/react/bridge/JavaScriptModule {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/SoftAssertions.kt

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.bridge
+
+/**
+ * Utility class to make assertions that should not hard-crash the app but instead be handled by the
+ * Catalyst app [JSExceptionHandler]. See the javadoc on that class for more information about our
+ * opinion on when these assertions should be used as opposed to assertions that might throw
+ * AssertionError Throwables that will cause the app to hard crash.
+ */
+public object SoftAssertions {
+
+  /**
+   * Throw [AssertionException] with a given message. Use this method surrounded with `if` block
+   * with assert condition in case you plan to do string concatenation to produce the message. This
+   * logs an assertion with ReactSoftExceptionLogger, which decides whether or not to actually
+   * throw.
+   */
+  @JvmStatic
+  public fun assertUnreachable(message: String): Unit {
+    ReactSoftExceptionLogger.logSoftException("SoftAssertions", AssertionException(message))
+  }
+
+  /**
+   * Asserts the given condition, throwing an [AssertionException] if the condition doesn't hold.
+   * This logs an assertion with ReactSoftExceptionLogger, which decides whether or not to actually
+   * throw.
+   */
+  @JvmStatic
+  public fun assertCondition(condition: Boolean, message: String): Unit {
+    if (!condition) {
+      ReactSoftExceptionLogger.logSoftException("SoftAssertions", AssertionException(message))
+    }
+  }
+
+  /**
+   * Asserts that the given object isn't null, throwing an [AssertionException] if it was. This logs
+   * an assertion with ReactSoftExceptionLogger, which decides whether or not to actually throw.
+   */
+  @JvmStatic
+  public fun <T> assertNotNull(instance: T?): T? {
+    if (instance == null) {
+      ReactSoftExceptionLogger.logSoftException(
+          "SoftAssertions", AssertionException("Expected object to not be null!"))
+    }
+    return instance
+  }
+}