From a2ca7cb081ff10c03ba647e9265a668da795e506 Mon Sep 17 00:00:00 2001
From: Sergeev Viktor <sergeevViktor017@gmail.com>
Date: Wed, 28 Jan 2026 01:48:19 +0300
Subject: [PATCH] ISSUES-86: fix arguments checked - fix comparison question
 symbol (it is a char, not a string) - fixed argument validation in
 'partialApplyProcedure': null arguments are not passed to the unboundArgs
 array

---
 .../java/com/dashjoin/jsonata/Jsonata.java    | 17 ++++++++++------
 .../dashjoin/jsonata/CustomFunctionTest.java  | 20 +++++++++++++++++++
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/dashjoin/jsonata/Jsonata.java b/src/main/java/com/dashjoin/jsonata/Jsonata.java
index 5cc6a7e..b66fe47 100644
--- a/src/main/java/com/dashjoin/jsonata/Jsonata.java
+++ b/src/main/java/com/dashjoin/jsonata/Jsonata.java
@@ -33,6 +33,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Objects;
 import java.util.concurrent.Callable;
 import java.util.function.BiFunction;
 import java.util.function.Function;
@@ -1821,7 +1822,7 @@ Object evaluateLambda(Symbol expr, Object input, Frame environment) {
         var evaluatedArgs = new ArrayList<>();
         for(var ii = 0; ii < expr.arguments.size(); ii++) {
             var arg = expr.arguments.get(ii);
-            if (arg.type.equals("operator") && (arg.value.equals("?"))) {
+            if (arg.type.equals("operator") &&  Objects.equals('?', arg.value)) {
                 evaluatedArgs.add(arg);
             } else {
                 evaluatedArgs.add(/* await */ evaluate(arg, input, environment));
@@ -1901,7 +1902,7 @@ Object validateArguments(Object signature, Object args, Object context) {
       * @param {Array} args - Arguments
       * @returns {{lambda: boolean, input: *, environment: {bind, lookup}, arguments: Array, body: *}} Result of partially applied procedure
       */
-    Object partialApplyProcedure(Symbol proc, List<Symbol> args) {
+    Object partialApplyProcedure(Symbol proc, List args) {
         // create a closure, bind the supplied parameters and return a Object that takes the remaining (?) parameters
         // Note Uli: if no env, bind to default env so the native functions can be found
         var env = createFrame(proc.environment!=null ? proc.environment : this.environment);
@@ -1910,11 +1911,15 @@ Object partialApplyProcedure(Symbol proc, List<Symbol> args) {
         for (var param : proc.arguments) {
 //         proc.arguments.forEach(Object (param, index) {
             Object arg = index<args.size() ? args.get(index) : null;
-            if ((arg==null) || (arg instanceof Symbol && ("operator".equals(((Symbol)arg).type) && "?".equals(((Symbol)arg).value)))) {
-                unboundArgs.add(param);
-            } else {
-                env.bind((String)param.value, arg);
+            if (arg instanceof Symbol) {
+                Symbol sym = (Symbol) arg;
+                if ("operator".equals(sym.type) && Objects.equals('?', sym.value)) {
+                    unboundArgs.add(param);
+                    index++;
+                    continue;
+                }
             }
+            env.bind((String)param.value, arg);
             index++;
         }
         var procedure = parser.new Symbol();
diff --git a/src/test/java/com/dashjoin/jsonata/CustomFunctionTest.java b/src/test/java/com/dashjoin/jsonata/CustomFunctionTest.java
index 3005e06..3d65453 100644
--- a/src/test/java/com/dashjoin/jsonata/CustomFunctionTest.java
+++ b/src/test/java/com/dashjoin/jsonata/CustomFunctionTest.java
@@ -1,7 +1,11 @@
 package com.dashjoin.jsonata;
 
+import java.io.IOException;
+import java.nio.charset.Charset;
 import java.util.List;
 import java.util.Map;
+
+import com.dashjoin.jsonata.json.Json;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
@@ -85,4 +89,20 @@ public Object call(Object input, @SuppressWarnings("rawtypes") List args) throws
     Assertions.assertEquals("T0410", ex.getError());
     Assertions.assertEquals("append", ex.getExpected());
   }
+
+  @Test
+  public void testMapWithAppend() throws IOException {
+    Object answer = Json.parseJson("{\"systems\": \"asd\"}");
+    var expression = Jsonata.jsonata("{'systems': 'asd'}.$map($, $append(?))");
+    Object evaluate = expression.evaluate(null);
+    Assertions.assertEquals(answer, evaluate);
+  }
+
+  @Test
+  public void testMapWithAppend2() {
+    Object answer = Json.parseJson("{\"systems\": \"asd\"}");
+    var expression = Jsonata.jsonata("$map($, $append(?))");
+    Object evaluate = expression.evaluate(answer);
+    Assertions.assertEquals(answer, evaluate);
+  }
 }