lucamolteni commented on code in PR #5617:
URL:
https://github.com/apache/incubator-kie-drools/pull/5617#discussion_r1417577669
##########
drools-model/drools-mvel-compiler/src/main/java/org/drools/mvelcompiler/util/MethodResolutionUtils.java:
##########
@@ -0,0 +1,183 @@
+package org.drools.mvelcompiler.util;
+
+import com.github.javaparser.ast.NodeList;
+import com.github.javaparser.ast.expr.Expression;
+import com.github.javaparser.ast.expr.MethodCallExpr;
+import com.github.javaparser.utils.Pair;
+import org.drools.mvel.parser.ast.expr.ListCreationLiteralExpression;
+import org.drools.mvel.parser.ast.expr.MapCreationLiteralExpression;
+import org.drools.mvel.parser.ast.visitor.DrlGenericVisitor;
+import org.drools.mvelcompiler.ast.ListExprT;
+import org.drools.mvelcompiler.ast.MapExprT;
+import org.drools.mvelcompiler.ast.TypedExpression;
+import org.drools.mvelcompiler.context.MvelCompilerContext;
+import org.drools.util.ClassUtils;
+import org.drools.util.MethodUtils;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+public final class MethodResolutionUtils {
+
+ private MethodResolutionUtils() {
+ // It is forbidden to create instances of util classes.
+ }
+
+ /**
+ * [] is ambiguous in mvel - it can represent an empty list or an empty
map.
+ * It cannot be distinguished on a language level, so this is a
workaround:
+ * - When there [] written in a rule, mvel parser parses it as an empty
list.
+ * - The only possible way with constructors, when there is such
parameter, is try to guess the correct parameter type when trying to read the
constructor from a class.
+ * - This uses all indexes of empty lists or empty maps in the
constructor parameters.
+ * - When not possible to resolve the constructor with a list or map
parameter, it will try to resolve a constructor with the other collection
parameter.
+ * - This happens for all empty list and map parameters resolved by the
parser, until a proper constructor is found.
+ */
+ public static List<TypedExpression> coerceCorrectConstructorArguments(
+ final Class<?> type,
+ List<TypedExpression> arguments,
+ List<Integer> emptyListArgumentIndexes) {
+ // Rather work only with the argumentsType and when a method is
resolved, flip the arguments list based on it.
+ final List<TypedExpression> coercedArgumentsTypesList = new
ArrayList<>(arguments);
+ // This needs to go through all possible combinations.
+ final int indexesListSize = emptyListArgumentIndexes.size();
Review Comment:
Add unit tests for this method as well
##########
drools-model/drools-mvel-compiler/src/main/java/org/drools/mvelcompiler/MethodCallExprVisitor.java:
##########
@@ -89,43 +87,21 @@ private MethodCallExprT parseMethod(MethodCallExpr n,
Optional<TypedExpression> scope,
TypedExpression name,
List<TypedExpression> arguments,
- Class<?>[] argumentsType) {
- Optional<Method> method = scope.flatMap(TypedExpression::getType)
- .<Class<?>>map(ClassUtils::classFromType)
- .map(scopeClazz -> MethodUtils.findMethod(scopeClazz,
n.getNameAsString(), argumentsType));
-
- if (method.isEmpty()) {
- method = mvelCompilerContext.getRootPattern()
- .map(scopeClazz -> MethodUtils.findMethod(scopeClazz,
n.getNameAsString(), argumentsType));
- if(method.isPresent()) {
- scope = mvelCompilerContext.createRootTypePrefix();
- }
+ List<Integer>
emptyCollectionArgumentIndexes) {
+ Pair<Optional<Method>, Optional<TypedExpression>> resolveMethodResult =
+ MethodResolutionUtils.resolveMethod(n, mvelCompilerContext,
scope, arguments);
+ // This is a workaround for mvel empty list and map ambiguity, please
see the description in getTypedArguments() method.
+ if (resolveMethodResult.a.isEmpty() &&
!emptyCollectionArgumentIndexes.isEmpty()) {
+ resolveMethodResult =
MethodResolutionUtils.resolveMethodWithEmptyCollectionArguments(n,
mvelCompilerContext, resolveMethodResult.b, arguments,
emptyCollectionArgumentIndexes);
Review Comment:
Can you please add unit tests in `drools-mvel-compiler` module covering this
case?
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