perf(extensions): validate JSON without allocating argument trees

android/app/src/androidTest/kotlin/com/zarz/spotiflac/ExtensionInputValidationTest.kt

@@ -0,0 +1,28 @@
+package com.zarz.spotiflac
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.spotiflac.backend.JsExtension
+import com.spotiflac.backend.JsExtensionException
+import org.json.JSONObject
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class ExtensionInputValidationTest {
+    @Test
+    fun invalidArgumentsDoNotReachJavaScriptAndValidObjectsKeepTheirValues() {
+        val source = "let calls=0; registerExtension({echo(value){return {calls:++calls,value}}});"
+        JsExtension(source, "{}", 2000uL).use { runtime ->
+            for (input in listOf("{}", "[1e400]", "[\"\\uD800\"]", "[] true")) {
+                val failure = runCatching { runtime.call("echo", input, null, 2000uL) }.exceptionOrNull()
+                assertTrue(failure is JsExtensionException.InvalidInput)
+            }
+            val result = JSONObject(runtime.call("echo", "[{\"title\":\"音楽 🎵\",\"options\":[true,null,42]}]", null, 2000uL))
+            assertEquals(1, result.getInt("calls"))
+            assertEquals("音楽 🎵", result.getJSONObject("value").getString("title"))
+            assertEquals(42, result.getJSONObject("value").getJSONArray("options").getInt(2))
+        }
+    }
+}