From 8b2b612da5d815d72cf4ddc74d2702f958bf54d5 Mon Sep 17 00:00:00 2001
From: Philipp Ossler <philipp.ossler@gmail.com>
Date: Wed, 18 Dec 2024 12:31:51 +0100
Subject: [PATCH] refactor: Move function validation

Move the function validation in the interpreter before invoking the function.
---
 .../feel/impl/builtin/BuiltinFunction.scala    | 16 +++++-----------
 .../impl/interpreter/FeelInterpreter.scala     | 18 ++++++++++++++----
 2 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/src/main/scala/org/camunda/feel/impl/builtin/BuiltinFunction.scala b/src/main/scala/org/camunda/feel/impl/builtin/BuiltinFunction.scala
index 12f347b23..8d9368029 100644
--- a/src/main/scala/org/camunda/feel/impl/builtin/BuiltinFunction.scala
+++ b/src/main/scala/org/camunda/feel/impl/builtin/BuiltinFunction.scala
@@ -16,7 +16,7 @@
  */
 package org.camunda.feel.impl.builtin
 
-import org.camunda.feel.syntaxtree.{Val, ValError, ValFatalError, ValFunction}
+import org.camunda.feel.syntaxtree.{Val, ValError, ValFunction}
 
 object BuiltinFunction {
 
@@ -27,20 +27,14 @@ object BuiltinFunction {
   ): ValFunction = {
     ValFunction(
       params = params,
-      invoke = validateArgs.orElse(invoke).orElse(error),
+      invoke = invoke.orElse(error),
       hasVarArgs = hasVarArgs
     )
   }
 
-  private def validateArgs: PartialFunction[List[Val], Any] = {
-    case args if args.exists(_.isInstanceOf[ValFatalError]) => args.find(_.isInstanceOf[ValFatalError]).get
-    case args if args.exists(_.isInstanceOf[ValError]) => args.find(_.isInstanceOf[ValError]).get
-  }
-
-  private def error: PartialFunction[List[Val], Any] = {
-    case args =>
-      val argumentList = args.map("'" + _ + "'").mkString(", ")
-      ValError(s"Illegal arguments: $argumentList")
+  private def error: PartialFunction[List[Val], Any] = { case args =>
+    val argumentList = args.map("'" + _ + "'").mkString(", ")
+    ValError(s"Illegal arguments: $argumentList")
   }
 
 }
diff --git a/src/main/scala/org/camunda/feel/impl/interpreter/FeelInterpreter.scala b/src/main/scala/org/camunda/feel/impl/interpreter/FeelInterpreter.scala
index 60072b841..f721a22fc 100644
--- a/src/main/scala/org/camunda/feel/impl/interpreter/FeelInterpreter.scala
+++ b/src/main/scala/org/camunda/feel/impl/interpreter/FeelInterpreter.scala
@@ -249,6 +249,7 @@ class FeelInterpreter(private val valueMapper: ValueMapper) {
             findFunction(context, name, params),
             f =>
               invokeFunction(f, params) match {
+                case fatalError: ValFatalError             => fatalError
                 case ValError(failure) if name == "assert" =>
                   error(EvaluationFailureType.ASSERT_FAILURE, failure)
                   ValError(failure)
@@ -727,10 +728,19 @@ class FeelInterpreter(private val valueMapper: ValueMapper) {
       }
     }
 
-    function.invoke(paramList) match {
-      case fatalError: ValFatalError => fatalError
-      case e: ValError               => e
-      case result                    => context.valueMapper.toVal(result)
+    // validate parameters
+    if (paramList.exists(_.isInstanceOf[ValFatalError])) {
+      paramList.find(_.isInstanceOf[ValFatalError]).get
+
+    } else if (paramList.exists(_.isInstanceOf[ValError])) {
+      paramList.find(_.isInstanceOf[ValError]).get
+
+    } else {
+      function.invoke(paramList) match {
+        case fatalError: ValFatalError => fatalError
+        case e: ValError               => e
+        case result                    => context.valueMapper.toVal(result)
+      }
     }
   }