- Add warnings for deprecated DRL syntax when used in DRL6

drools-drl/drools-drl-ast/src/main/java/org/drools/drl/ast/dsl/DescrBuilder.java

@@ -88,4 +88,14 @@ public DescrBuilder<P, T> endLocation( int line,
      * @return
      */
     public P end();
+
+    /**
+     * Returns the parent container of this descr builder.
+     * Example: ruleDescrBuilder.getParent() will return the
+     * PackageDescrBuilder as that is its parent container
+     * without ending the current construction.
+     *
+     * @return
+     */
+    public P getParent();
 }

drools-drl/drools-drl-ast/src/main/java/org/drools/drl/ast/dsl/impl/BaseDescrBuilderImpl.java

@@ -72,4 +72,8 @@ public P end() {
         return parent;
     }
 
+    @Override
+    public P getParent() {
+        return parent;
+    }
 }

drools-drl/drools-drl-parser-tests/src/test/java/org/drools/drl/parser/antlr4/DRLExprParserTest.java

@@ -576,4 +576,48 @@ void newBigDecimal() {
         assertThat(bind.getVariable()).isEqualTo("$bd");
         assertThat(bind.getExpression()).isEqualTo("new BigDecimal(30)");
     }
+
+    @Test
+    void halfConstraintAnd() {
+        String source = "age > 10 && < 20";
+        parser.parse(source);
+
+        if (DrlParser.ANTLR4_PARSER_ENABLED) {
+            // half constraint is dropped in DRL10
+            assertThat(parser.hasErrors()).isTrue();
+        } else {
+            assertThat(parser.hasErrors()).as(parser.getErrors().toString()).isFalse();
+        }
+    }
+
+    @Test
+    void halfConstraintOr() {
+        String source = "name == \"John\" || == \"Paul\"";
+        parser.parse(source);
+
+        if (DrlParser.ANTLR4_PARSER_ENABLED) {
+            // half constraint is dropped in DRL10
+            assertThat(parser.hasErrors()).isTrue();
+        } else {
+            assertThat(parser.hasErrors()).as(parser.getErrors().toString()).isFalse();
+        }
+    }
+
+    @Test
+    void customOperator() {
+        Operator.addOperatorToRegistry("supersetOf", false);
+        // prefix '##' is required for custom operators in DRL10
+        String source = DrlParser.ANTLR4_PARSER_ENABLED ? "this ##supersetOf $list" : "this supersetOf $list";
+        ConstraintConnectiveDescr result = parser.parse(source);
+        assertThat(parser.hasErrors()).as(parser.getErrors().toString()).isFalse();
+
+        RelationalExprDescr rel = (RelationalExprDescr) result.getDescrs().get(0);
+        assertThat(rel.getOperator()).isEqualTo("supersetOf");
+
+        AtomicExprDescr left = (AtomicExprDescr) rel.getLeft();
+        assertThat(left.getExpression()).isEqualTo("this");
+
+        AtomicExprDescr right = (AtomicExprDescr) rel.getRight();
+        assertThat(right.getExpression()).isEqualTo("$list");
+    }
 }

drools-drl/drools-drl-parser-tests/src/test/java/org/drools/drl/parser/antlr4/MiscDRLParserTest.java

@@ -5320,4 +5320,24 @@ void typeDeclarationWithTypeToken() {
         TypeFieldDescr typeFieldDescr = typeDeclarationDescr.getFields().get("id");
         assertThat(typeFieldDescr.getPattern().getObjectType()).isEqualTo("int");
     }
+
+    @Test
+    void agendaGroup() {
+        final String drl = "rule R1\n" +
+                "  agenda-group \"group1\"\n" +
+                "  when\n" +
+                "  then\n" +
+                "end";
+        PackageDescr pkg = parseAndGetPackageDescrWithoutErrorCheck(drl);
+        if (DrlParser.ANTLR4_PARSER_ENABLED) {
+            // agenda-group is dropped in DRL10
+            assertThat(parser.hasErrors()).isTrue();
+        } else {
+            RuleDescr rule = pkg.getRules().get(0);
+            assertThat(rule).isNotNull();
+            final AttributeDescr att = rule.getAttributes().get("agenda-group");
+            assertThat(att.getValue()).isEqualTo("group1");
+            assertThat(att.getName()).isEqualTo("agenda-group");
+        }
+    }
 }

drools-drl/drools-drl-parser/src/main/java/org/drools/drl/parser/DrlParser.java

@@ -74,6 +74,11 @@ public DrlParser() {
 
     public DrlParser(LanguageLevelOption languageLevel) {
         this.languageLevel = languageLevel;
+
+        if (languageLevel == LanguageLevelOption.DRL5 || languageLevel == LanguageLevelOption.DRL6_STRICT) {
+            LOG.warn("{} is deprecated and will be removed in future versions. Please use the default {} or newly introduced {} instead.",
+                     languageLevel, LanguageLevelOption.DRL6, LanguageLevelOption.DRL10);
+        }
     }
 
     /** Parse a rule from text */

drools-drl/drools-drl-parser/src/main/java/org/drools/drl/parser/lang/DRL6Parser.java

@@ -1558,6 +1558,7 @@ public AttributeDescr attribute(AttributeSupportBuilder<?> as) {
                             DroolsSoftKeywords.GROUP)) {
                 attribute = stringAttribute(as,
                         new String[]{DroolsSoftKeywords.AGENDA, "-", DroolsSoftKeywords.GROUP});
+                helper.logAgendaGroupWarn(attribute);
             } else if (helper.validateIdentifierKey(DroolsSoftKeywords.ACTIVATION) &&
                     helper.validateLT(2,
                             "-") &&
@@ -2155,6 +2156,7 @@ private BaseDescr lhsOr(final CEDescrBuilder<?, ?> ce,
                 while (input.LA(1) == DRL6Lexer.AT) {
                     // annotation*
                     annotation(or);
+                    helper.logAnnotationInLhsPatternWarn(or);
                     if (state.failed)
                         return null;
                 }
@@ -2212,6 +2214,7 @@ private BaseDescr lhsOr(final CEDescrBuilder<?, ?> ce,
                                     null,
                                     null,
                                     DroolsEditorType.SYMBOL);
+                            helper.logInfixOrWarn(or);
                         } else {
                             match(input,
                                     DRL6Lexer.ID,
@@ -2225,6 +2228,7 @@ private BaseDescr lhsOr(final CEDescrBuilder<?, ?> ce,
                         while (input.LA(1) == DRL6Lexer.AT) {
                             // annotation*
                             annotation(or);
+                            helper.logAnnotationInLhsPatternWarn(or);
                             if (state.failed)
                                 return null;
                         }
@@ -2299,6 +2303,7 @@ private BaseDescr lhsAnd(final CEDescrBuilder<?, ?> ce,
                 while (input.LA(1) == DRL6Lexer.AT) {
                     // annotation*
                     annotation(and);
+                    helper.logAnnotationInLhsPatternWarn(and);
                     if (state.failed)
                         return null;
                 }
@@ -2354,6 +2359,7 @@ private BaseDescr lhsAnd(final CEDescrBuilder<?, ?> ce,
                                     null,
                                     null,
                                     DroolsEditorType.SYMBOL);
+                            helper.logInfixAndWarn(and);
                         } else {
                             match(input,
                                     DRL6Lexer.ID,
@@ -2367,6 +2373,7 @@ private BaseDescr lhsAnd(final CEDescrBuilder<?, ?> ce,
                         while (input.LA(1) == DRL6Lexer.AT) {
                             // annotation*
                             annotation(and);
+                            helper.logAnnotationInLhsPatternWarn(and);
                             if (state.failed)
                                 return null;
                         }

drools-drl/drools-drl-parser/src/main/java/org/drools/drl/parser/lang/ParserHelper.java

@@ -20,19 +20,26 @@
 
 import java.util.ArrayDeque;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Deque;
 import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
 
 import org.antlr.runtime.CommonToken;
 import org.antlr.runtime.RecognitionException;
 import org.antlr.runtime.RecognizerSharedState;
 import org.antlr.runtime.Token;
 import org.antlr.runtime.TokenStream;
+import org.drools.drl.ast.descr.AnnotatedBaseDescr;
 import org.drools.drl.ast.descr.AttributeDescr;
 import org.drools.drl.ast.descr.BaseDescr;
+import org.drools.drl.ast.descr.RelationalExprDescr;
+import org.drools.drl.ast.descr.RuleDescr;
 import org.drools.drl.ast.dsl.AbstractClassTypeDeclarationBuilder;
 import org.drools.drl.ast.dsl.AccumulateDescrBuilder;
 import org.drools.drl.ast.dsl.AccumulateImportDescrBuilder;
@@ -65,13 +72,18 @@
 import org.drools.drl.ast.dsl.UnitDescrBuilder;
 import org.drools.drl.ast.dsl.WindowDeclarationDescrBuilder;
 import org.drools.drl.parser.DroolsParserException;
+import org.drools.drl.parser.impl.Operator;
 import org.kie.internal.builder.conf.LanguageLevelOption;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * This is a class to hold all the helper functions/methods used
  * by the DRL parser
  */
 public class ParserHelper {
+    public static final Logger LOG = LoggerFactory.getLogger(ParserHelper.class );
+
     public final String[]                             statementKeywords        = new String[]{
                                                                                DroolsSoftKeywords.PACKAGE,
                                                                                DroolsSoftKeywords.UNIT,
@@ -100,6 +112,17 @@ public class ParserHelper {
 
     private final LanguageLevelOption                 languageLevel;
 
+    private static final Set<String> BUILT_IN_OPERATORS = Arrays.stream(Operator.BuiltInOperator.values())
+            .map(Operator.BuiltInOperator::getSymbol)
+            .collect(Collectors.toSet());
+
+    private static int logCounterHalfConstraint = 0;
+    private static int logCounterCustomOperator = 0;
+    private static int logCounterInfixAnd = 0;
+    private static int logCounterInfixOr = 0;
+    private static int logCounterAnnotationInLhsPattern = 0;
+    private static int logCounterAgendaGroup = 0;
+
     public ParserHelper(TokenStream input,
                         RecognizerSharedState state,
                         LanguageLevelOption languageLevel) {
@@ -656,4 +679,123 @@ void setEnd( DescrBuilder< ? , ? > db ) {
     public String[] getStatementKeywords() {
         return statementKeywords;
     }
+
+    public static void logHalfConstraintWarn(String logicalConstraint, BaseDescr descr) {
+        if (descr instanceof RelationalExprDescr relational) {
+            String halfConstraintStr = logicalConstraint + " " + relational.getOperator() + " " + relational.getRight().toString();
+            logHalfConstraintWarn("The use of a half constraint '" + halfConstraintStr + "' is deprecated" +
+                                          " and will be removed in the future version (LanguageLevel.DRL10)." +
+                                          " Please add a left operand.");
+        }
+    }
+
+    public static void logHalfConstraintWarn(String message) {
+        if (logCounterHalfConstraint > 10) {
+            return; // suppress further warnings
+        }
+
+        logCounterHalfConstraint++;
+        LOG.warn(message);
+        if (logCounterHalfConstraint == 10) {
+            LOG.warn("Further warnings about half constraints will be suppressed.");
+        }
+    }
+
+    public static void logCustomOperatorWarn(Token token) {
+        if (logCounterCustomOperator > 1) {
+            return; // suppress further warnings
+        }
+
+        String operator = token.getText();
+        if (BUILT_IN_OPERATORS.contains(operator)) {
+            return; // built-in operator
+        }
+        logCounterCustomOperator++;
+        LOG.warn("Custom operator will require a prefix '##' in the future version (LanguageLevel.DRL10)." +
+                         " If you use LanguageLevel.DRL10, you need to change '{}' to '##{}'." +
+                         " You don't need to change the rule while you use the default LanguageLevel.DRL6.", operator, operator);
+    }
+
+    public static void logInfixOrWarn(CEDescrBuilder descrBuilder) {
+        if (logCounterInfixOr > 5) {
+            return; // suppress further warnings
+        }
+
+        Optional<RuleDescr> ruleDescrOpt = getParentRuleDescr(descrBuilder);
+        if (ruleDescrOpt.isEmpty()) {
+            return;
+        }
+
+        logCounterInfixOr++;
+        LOG.warn("Connecting patterns with '||' is deprecated and will be removed in the future version (LanguageLevel.DRL10)." +
+                         " Please replace '||' with 'or' in rule '{}'. '||' in a constraint will remain supported.", ruleDescrOpt.get().getName());
+        if (logCounterInfixOr == 5) {
+            LOG.warn("Further warnings about '||' will be suppressed.");
+        }
+    }
+
+    public static void logInfixAndWarn(CEDescrBuilder descrBuilder) {
+        if (logCounterInfixAnd > 5) {
+            return; // suppress further warnings
+        }
+
+        Optional<RuleDescr> ruleDescrOpt = getParentRuleDescr(descrBuilder);
+        if (ruleDescrOpt.isEmpty()) {
+            return;
+        }
+
+        logCounterInfixAnd++;
+        LOG.warn("Connecting patterns with '&&' is deprecated and will be removed in the future version (LanguageLevel.DRL10)." +
+                         " Please replace '&&' with 'and' in rule '{}'. '&&' in a constraint will remain supported.", ruleDescrOpt.get().getName());
+        if (logCounterInfixAnd == 5) {
+            LOG.warn("Further warnings about '&&' will be suppressed.");
+        }
+    }
+
+    private static Optional<RuleDescr> getParentRuleDescr(DescrBuilder<?, ?> descrBuilder) {
+        while (descrBuilder != null) {
+            if (descrBuilder instanceof RuleDescrBuilder) {
+                return Optional.of(((RuleDescrBuilder) descrBuilder).getDescr());
+            } else if (descrBuilder instanceof PackageDescrBuilder) {
+                return Optional.empty();
+            }
+            descrBuilder = descrBuilder.getParent();
+        }
+        return Optional.empty();
+    }
+
+    public static void logAnnotationInLhsPatternWarn(CEDescrBuilder descrBuilder) {
+        if (logCounterAnnotationInLhsPattern > 5) {
+            return; // suppress further warnings
+        }
+
+        Optional<RuleDescr> ruleDescrOpt = getParentRuleDescr(descrBuilder);
+        if (ruleDescrOpt.isEmpty()) {
+            return;
+        }
+
+        BaseDescr descr = descrBuilder.getDescr();
+        if (descr instanceof AnnotatedBaseDescr annotated) {
+            String annotationNames = annotated.getAnnotationNames().stream().collect(Collectors.joining(", "));
+            logCounterAnnotationInLhsPattern++;
+            LOG.warn("Annotation inside LHS patterns is deprecated and will be removed in the future version (LanguageLevel.DRL10)." +
+                             " Found '{}' in rule '{}'. Annotation in other places will remain supported.", annotationNames, ruleDescrOpt.get().getName());
+            if (logCounterAnnotationInLhsPattern == 5) {
+                LOG.warn("Further warnings about Annotation inside LHS patterns will be suppressed.");
+            }
+        }
+    }
+
+    public static void logAgendaGroupWarn(AttributeDescr attributeDescr) {
+        if (logCounterAgendaGroup > 5) {
+            return; // suppress further warnings
+        }
+
+        logCounterAgendaGroup++;
+        LOG.warn("'agenda-group \"{}\"' is found. 'agenda-group' is deprecated and will be dropped in the future version (LanguageLevel.DRL10)." +
+                         " Please replace 'agenda-group' with 'ruleflow-group', which works as the same as 'agenda-group'.", attributeDescr.getValue());
+        if (logCounterAgendaGroup == 5) {
+            LOG.warn("Further warnings about 'agenda-group' will be suppressed.");
+        }
+    }
 }

drools-drl/drools-drl-parser/src/main/resources/org/drools/drl/parser/DRL6Expressions.g

@@ -432,6 +432,7 @@ orRestriction returns [BaseDescr result]
   : left=andRestriction { if( buildDescr  ) { $result = $left.result; } }
     ( (DOUBLE_PIPE fullAnnotation[null]? andRestriction)=>lop=DOUBLE_PIPE args=fullAnnotation[null]? right=andRestriction
          { if( buildDescr ) {
+               helper.logHalfConstraintWarn("||", right);
                ConstraintConnectiveDescr descr = ConstraintConnectiveDescr.newOr();
                descr.addOrMerge( $result );
                descr.addOrMerge( $right.result );
@@ -448,6 +449,7 @@ andRestriction returns [BaseDescr result]
   	    { if ( isNotEOF() ) helper.emit( Location.LOCATION_LHS_INSIDE_CONDITION_OPERATOR ); }
         args=fullAnnotation[null]?right=singleRestriction
          { if( buildDescr  ) {
+               helper.logHalfConstraintWarn("&&", right);
                ConstraintConnectiveDescr descr = ConstraintConnectiveDescr.newAnd();
                descr.addOrMerge( $result );
                descr.addOrMerge( $right.result );
@@ -847,9 +849,9 @@ in_key
   ;
 
 operator_key
-  :      {(helper.isPluggableEvaluator(false))}?=> id=ID { helper.emit($ID, DroolsEditorType.KEYWORD); }
+  :      {(helper.isPluggableEvaluator(false))}?=> id=ID { helper.logCustomOperatorWarn(id); helper.emit($ID, DroolsEditorType.KEYWORD); }
   ;
 
 neg_operator_key
-  :      {(helper.isPluggableEvaluator(true))}?=> id=ID { helper.emit($ID, DroolsEditorType.KEYWORD); }
+  :      {(helper.isPluggableEvaluator(true))}?=> id=ID { helper.logCustomOperatorWarn(id); helper.emit($ID, DroolsEditorType.KEYWORD); }
   ;