Output fixed in case of an incorrect arguments count in custom scenarios

src/jvm/main/org/jetbrains/kotlinx/lincheck/CustomScenarioDSL.kt

@@ -44,6 +44,8 @@ fun scenario(block: DSLScenarioBuilder.() -> Unit): ExecutionScenario =
 internal fun actor(f: KFunction<*>, vararg args: Any?, cancelOnSuspension: Boolean = false): Actor {
     val method = f.javaMethod ?: throw IllegalStateException("The function is a constructor or cannot be represented by a Java Method")
     require(method.exceptionTypes.all { Throwable::class.java.isAssignableFrom(it) }) { "Not all declared exceptions are Throwable" }
+    val requiredArgsCount = method.parameters.size - if (f.isSuspend) 1 else 0
+    require(requiredArgsCount == args.size) { "The count of the supplied parameters for the ${f.name} method is incorrect: ${f.parameters.size} arguments expected, ${args.size} supplied." }
     return Actor(
         method = method,
         arguments = args.toList(),

src/jvm/test/org/jetbrains/kotlinx/lincheck_test/representation/IncorrectArgumentsCountInCustomScenarioActorTest.kt

@@ -0,0 +1,47 @@
+/*
+ * Lincheck
+ *
+ * Copyright (C) 2019 - 2024 JetBrains s.r.o.
+ *
+ * This Source Code Form is subject to the terms of the
+ * Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed
+ * with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+package org.jetbrains.kotlinx.lincheck_test.representation
+
+import org.jetbrains.kotlinx.lincheck.annotations.Operation
+import org.jetbrains.kotlinx.lincheck.strategy.managed.modelchecking.ModelCheckingOptions
+import org.jetbrains.kotlinx.lincheck_test.util.checkFailsWithException
+import org.junit.Assert
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class IncorrectArgumentsCountInCustomScenarioActorTest {
+
+    @Operation
+    fun operation(value: Int) = Unit
+
+    @Test
+    fun testTooFew() {
+        val exception = Assert.assertThrows(IllegalArgumentException::class.java) {
+            ModelCheckingOptions()
+                .addCustomScenario {
+                    parallel { thread { actor(::operation) } }
+                }
+        }
+        assertEquals("The count of the supplied parameters for the operation method is incorrect: 1 arguments expected, 0 supplied.", exception.message)
+    }
+
+    @Test
+    fun testTooMany() {
+        val exception = Assert.assertThrows(IllegalArgumentException::class.java) {
+            ModelCheckingOptions()
+                .addCustomScenario {
+                    parallel { thread { actor(::operation, 1, 2) } }
+                }
+        }
+        assertEquals("The count of the supplied parameters for the operation method is incorrect: 1 arguments expected, 2 supplied.", exception.message)
+    }
+
+}