From 5fe50b40d3f44aa34feb6be1d4bac3c4c177daf5 Mon Sep 17 00:00:00 2001
From: Toshiya Kobayashi <toshiyakobayashi@gmail.com>
Date: Mon, 20 May 2024 13:57:23 +0900
Subject: [PATCH] - Exclude 'new' from 'drlIdentifier' because of 'primary'
 ambiguity - Add tests

---
 .../drl/parser/antlr4/DRLExprParserTest.java  | 37 +++++++++++++++++++
 .../drl/parser/antlr4/ParserTestUtils.java    |  4 +-
 .../drl/parser/antlr4/DRL6Expressions.g4      |  2 +-
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/drools-drl/drools-drl-parser-tests/src/test/java/org/drools/drl/parser/antlr4/DRLExprParserTest.java b/drools-drl/drools-drl-parser-tests/src/test/java/org/drools/drl/parser/antlr4/DRLExprParserTest.java
index 3a2aee51167..6489f3fdf80 100644
--- a/drools-drl/drools-drl-parser-tests/src/test/java/org/drools/drl/parser/antlr4/DRLExprParserTest.java
+++ b/drools-drl/drools-drl-parser-tests/src/test/java/org/drools/drl/parser/antlr4/DRLExprParserTest.java
@@ -440,6 +440,30 @@ public void testExtraneousInput() {
         }
     }
 
+    @Test
+    public void testNoViableAlt() {
+        String source = "a~a";
+        parser.parse(source);
+
+        // Backward Compatibility Notes:
+        //   Old expr parser (DRL6Expressions) allows this expression and only takes "a" ignoring the invalid part "~a" without emitting an error.
+        //   This is rather a bug in the old parser, and the new parser (ANTLR4) correctly emits an error for this case.
+        //   Backward compatibility doesn't seem to be required in this case.
+        if (DrlParser.ANTLR4_PARSER_ENABLED) {
+            assertThat(parser.hasErrors()).isTrue();
+            assertThat(parser.getErrors()).hasSize(1);
+            DroolsParserException exception = parser.getErrors().get(0);
+            assertThat(exception.getErrorCode()).isEqualTo("ERR 101");
+            assertThat(exception.getLineNumber()).isEqualTo(1);
+            assertThat(exception.getColumn()).isEqualTo(2);
+            assertThat(exception.getOffset()).isEqualTo(2);
+            assertThat(exception.getMessage())
+                    .isEqualToIgnoringCase("[ERR 101] Line 1:2 no viable alternative at input 'a'");
+        } else {
+            assertThat(parser.hasErrors()).isFalse();
+        }
+    }
+
     @Test
     void orWithMethodCall() {
         String source = "value == 10 || someMethod() == 4";
@@ -541,4 +565,17 @@ void andWithMethodCallWithArg() {
         assertThat(left.getExpression()).isEqualTo("someMethod(value)");
         assertThat(right.getExpression()).isEqualTo("4");
     }
+
+    @Test
+    void newBigDecimal() {
+        String source = "$bd : new BigDecimal(30)";
+        ConstraintConnectiveDescr result = parser.parse(source);
+        assertThat(parser.hasErrors()).as(parser.getErrors().toString()).isFalse();
+
+        assertThat(result.getDescrs().size()).isEqualTo(1);
+
+        BindingDescr bind = (BindingDescr) result.getDescrs().get(0);
+        assertThat(bind.getVariable()).isEqualTo("$bd");
+        assertThat(bind.getExpression()).isEqualTo("new BigDecimal(30)");
+    }
 }
diff --git a/drools-drl/drools-drl-parser-tests/src/test/java/org/drools/drl/parser/antlr4/ParserTestUtils.java b/drools-drl/drools-drl-parser-tests/src/test/java/org/drools/drl/parser/antlr4/ParserTestUtils.java
index 9d59344f376..3419eab65e5 100644
--- a/drools-drl/drools-drl-parser-tests/src/test/java/org/drools/drl/parser/antlr4/ParserTestUtils.java
+++ b/drools-drl/drools-drl-parser-tests/src/test/java/org/drools/drl/parser/antlr4/ParserTestUtils.java
@@ -25,12 +25,14 @@
 
 public class ParserTestUtils {
 
+    // 'new' is not included because it cannot be included in drlIdentifier.
+    // See https://github.com/apache/incubator-kie-drools/pull/5958
     public static List<String> javaKeywords =
             Arrays.asList(
                     "abstract", "assert", "boolean", "break", "byte", "case", "catch", "char", "class", "const",
                     "continue", "default", "do", "double", "else", "enum", "extends", "final", "finally", "float",
                     "for", "goto", "if", "implements", "import", "instanceof", "int", "interface", "long", "native",
-                    "new", "package", "private", "protected", "public", "return", "short", "static", "strictfp",
+                    "package", "private", "protected", "public", "return", "short", "static", "strictfp",
                     "super", "switch", "synchronized", "this", "throw", "throws", "transient", "try", "void", "volatile",
                     "while"
             );
diff --git a/drools-drl/drools-drl-parser/src/main/antlr4/org/drools/drl/parser/antlr4/DRL6Expressions.g4 b/drools-drl/drools-drl-parser/src/main/antlr4/org/drools/drl/parser/antlr4/DRL6Expressions.g4
index 3daf6ccf653..f2a5a79f195 100644
--- a/drools-drl/drools-drl-parser/src/main/antlr4/org/drools/drl/parser/antlr4/DRL6Expressions.g4
+++ b/drools-drl/drools-drl-parser/src/main/antlr4/org/drools/drl/parser/antlr4/DRL6Expressions.g4
@@ -193,7 +193,7 @@ drlIdentifier returns [Token token]
     | INTERFACE
     | LONG
     | NATIVE
-    | NEW
+//    | NEW     // avoid ambiguity with 'new_key creator' and 'drlIdentifier' in 'primary'
     | PACKAGE
     | PRIVATE
     | PROTECTED