refactor: apply local search fixes to VIATRA

9 files changed, 39 insertions, 523 deletions

diff --git a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/ViatraModelQueryBuilderImpl.java b/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/ViatraModelQueryBuilderImpl.java
index c8aa067c..cfdc43ba 100644
--- a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/ViatraModelQueryBuilderImpl.java
+++ b/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/ViatraModelQueryBuilderImpl.java
@@ -15,11 +15,11 @@ import tools.refinery.store.query.rewriter.DuplicateDnfRemover;
 import tools.refinery.store.query.rewriter.InputParameterResolver;
 import tools.refinery.store.query.viatra.ViatraModelQueryBuilder;
 import tools.refinery.store.query.viatra.internal.localsearch.FlatCostFunction;
-import tools.refinery.store.query.viatra.internal.localsearch.RelationalLocalSearchBackendFactory;
 import tools.refinery.store.query.viatra.internal.matcher.RawPatternMatcher;
 import tools.refinery.store.query.viatra.internal.pquery.Dnf2PQuery;
 import tools.refinery.viatra.runtime.api.IQuerySpecification;
 import tools.refinery.viatra.runtime.api.ViatraQueryEngineOptions;
+import tools.refinery.viatra.runtime.localsearch.matcher.integration.LocalSearchGenericBackendFactory;
 import tools.refinery.viatra.runtime.localsearch.matcher.integration.LocalSearchHintOptions;
 import tools.refinery.viatra.runtime.matchers.backend.IQueryBackendFactory;
 import tools.refinery.viatra.runtime.matchers.backend.QueryEvaluationHint;
@@ -43,7 +43,7 @@ public class ViatraModelQueryBuilderImpl extends AbstractModelAdapterBuilder<Via
                 engineOptionsBuilder = new ViatraQueryEngineOptions.Builder()
                                 .withDefaultBackend(ReteBackendFactory.INSTANCE)
                                 .withDefaultCachingBackend(ReteBackendFactory.INSTANCE)
-                                .withDefaultSearchBackend(RelationalLocalSearchBackendFactory.INSTANCE);
+                                .withDefaultSearchBackend(LocalSearchGenericBackendFactory.INSTANCE);
                 rewriter = new CompositeRewriter();
                 rewriter.addFirst(new DuplicateDnfRemover());
                 rewriter.addFirst(new InputParameterResolver());
diff --git a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/ExtendOperationExecutor.java b/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/ExtendOperationExecutor.java
deleted file mode 100644
index fc75198c..00000000
--- a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/ExtendOperationExecutor.java
+++ /dev/null
@@ -1,76 +0,0 @@
-/*******************************************************************************
- * Copyright (c) 2010-2013, Zoltan Ujhelyi, Akos Horvath, Istvan Rath and Daniel Varro
- * Copyright (c) 2023 The Refinery Authors <https://refinery.tools/>
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Public License v. 2.0 which is available at
- * http://www.eclipse.org/legal/epl-v20.html.
- * SPDX-License-Identifier: EPL-2.0
- *******************************************************************************/
-package tools.refinery.store.query.viatra.internal.localsearch;
-
-import tools.refinery.viatra.runtime.localsearch.MatchingFrame;
-import tools.refinery.viatra.runtime.localsearch.matcher.ISearchContext;
-import tools.refinery.viatra.runtime.localsearch.operations.ISearchOperation.ISearchOperationExecutor;
-
-import java.util.Iterator;
-
-/**
- * An operation that can be used to enumerate all possible values for a single position based on a constraint
- * @author Zoltan Ujhelyi, Akos Horvath
- * @since 2.0
- */
-abstract class ExtendOperationExecutor<T> implements ISearchOperationExecutor {
-
-    private Iterator<? extends T> it;
-
-    /**
-     * Returns an iterator with the possible options from the current state
-     * @since 2.0
-     */
-        @SuppressWarnings("squid:S1452")
-    protected abstract Iterator<? extends T> getIterator(MatchingFrame frame, ISearchContext context);
-    /**
-     * Updates the frame with the next element of the iterator. Called during {@link #execute(MatchingFrame, ISearchContext)}.
-     *
-     * @return true if the update is successful or false otherwise; in case of false is returned, the next element should be taken from the iterator.
-     * @since 2.0
-     */
-    protected abstract boolean fillInValue(T newValue, MatchingFrame frame, ISearchContext context);
-
-    /**
-     * Restores the frame to the state before {@link #fillInValue(Object, MatchingFrame, ISearchContext)}. Called during
-     * {@link #onBacktrack(MatchingFrame, ISearchContext)}.
-     *
-     * @since 2.0
-     */
-    protected abstract void cleanup(MatchingFrame frame, ISearchContext context);
-
-    @Override
-    public void onInitialize(MatchingFrame frame, ISearchContext context) {
-        it = getIterator(frame, context);
-    }
-
-    @Override
-    public void onBacktrack(MatchingFrame frame, ISearchContext context) {
-        it = null;
-
-    }
-
-        /**
-         * Fixed version of {@link tools.refinery.viatra.runtime.localsearch.operations.ExtendOperationExecutor#execute}
-         * that handles failed unification of variables correctly.
-         * @param frame The matching frame to extend.
-         * @param context The search context.
-         * @return {@code true} if an extension was found, {@code false} otherwise.
-         */
-    @Override
-    public boolean execute(MatchingFrame frame, ISearchContext context) {
-                while (it.hasNext()) {
-                        var newValue = it.next();
-                        if (fillInValue(newValue, frame, context)) {
-                                return true;
-                        }
-                }
-                return false;
-    }
-}
diff --git a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/ExtendPositivePatternCall.java b/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/ExtendPositivePatternCall.java
deleted file mode 100644
index b8b6b159..00000000
--- a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/ExtendPositivePatternCall.java
+++ /dev/null
@@ -1,117 +0,0 @@
-/*******************************************************************************
- * Copyright (c) 2010-2016, Grill Balázs, IncQueryLabs
- * Copyright (c) 2023 The Refinery Authors <https://refinery.tools/>
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Public License v. 2.0 which is available at
- * http://www.eclipse.org/legal/epl-v20.html.
- * SPDX-License-Identifier: EPL-2.0
- *******************************************************************************/
-package tools.refinery.store.query.viatra.internal.localsearch;
-
-import tools.refinery.viatra.runtime.localsearch.MatchingFrame;
-import tools.refinery.viatra.runtime.localsearch.matcher.ISearchContext;
-import tools.refinery.viatra.runtime.localsearch.operations.IPatternMatcherOperation;
-import tools.refinery.viatra.runtime.localsearch.operations.ISearchOperation;
-import tools.refinery.viatra.runtime.localsearch.operations.util.CallInformation;
-import tools.refinery.viatra.runtime.matchers.backend.IQueryResultProvider;
-import tools.refinery.viatra.runtime.matchers.tuple.Tuple;
-import tools.refinery.viatra.runtime.matchers.tuple.TupleMask;
-import tools.refinery.viatra.runtime.matchers.tuple.VolatileModifiableMaskedTuple;
-
-import java.util.Iterator;
-import java.util.List;
-import java.util.function.Function;
-
-/**
- * @author Grill Balázs
- * @since 1.4
- *
- */
-public class ExtendPositivePatternCall implements ISearchOperation, IPatternMatcherOperation {
-
-    private class Executor extends ExtendOperationExecutor<Tuple> {
-        private final VolatileModifiableMaskedTuple maskedTuple;
-
-        public Executor() {
-            maskedTuple = new VolatileModifiableMaskedTuple(information.getThinFrameMask());
-        }
-
-        @Override
-        protected Iterator<? extends Tuple> getIterator(MatchingFrame frame, ISearchContext context) {
-            maskedTuple.updateTuple(frame);
-            IQueryResultProvider matcher = context.getMatcher(information.getCallWithAdornment());
-            return matcher.getAllMatches(information.getParameterMask(), maskedTuple).iterator();
-        }
-
-        /**
-         * @since 2.0
-         */
-        @Override
-        protected boolean fillInValue(Tuple result, MatchingFrame frame, ISearchContext context) {
-            TupleMask mask = information.getFullFrameMask();
-            // The first loop clears out the elements from a possible previous iteration
-            for(int i : information.getFreeParameterIndices()) {
-                mask.set(frame, i, null);
-            }
-            for(int i : information.getFreeParameterIndices()) {
-                Object oldValue = mask.getValue(frame, i);
-                Object valueToFill = result.get(i);
-                if (oldValue != null && !oldValue.equals(valueToFill)){
-                    // If the inverse map contains more than one values for the same key, it means that these arguments are unified by the caller.
-                    // In this case if the callee assigns different values the frame shall be dropped
-                    return false;
-                }
-                mask.set(frame, i, valueToFill);
-            }
-            return true;
-        }
-
-        @Override
-        protected void cleanup(MatchingFrame frame, ISearchContext context) {
-            TupleMask mask = information.getFullFrameMask();
-            for(int i : information.getFreeParameterIndices()){
-                mask.set(frame, i, null);
-            }
-
-        }
-
-        @Override
-        public ISearchOperation getOperation() {
-            return ExtendPositivePatternCall.this;
-        }
-    }
-
-    private final CallInformation information;
-
-    /**
-     * @since 1.7
-     */
-    public ExtendPositivePatternCall(CallInformation information) {
-       this.information = information;
-    }
-
-    @Override
-    public ISearchOperationExecutor createExecutor() {
-        return new Executor();
-    }
-
-    @Override
-    public List<Integer> getVariablePositions() {
-        return information.getVariablePositions();
-    }
-
-    @Override
-    public String toString() {
-        return toString(Object::toString);
-    }
-
-    @Override
-    public String toString(@SuppressWarnings("squid:S4276") Function<Integer, String> variableMapping) {
-        return "extend find " + information.toString(variableMapping);
-    }
-
-    @Override
-    public CallInformation getCallInformation() {
-        return information;
-    }
-}
diff --git a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/GenericTypeExtend.java b/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/GenericTypeExtend.java
deleted file mode 100644
index 0ee69b88..00000000
--- a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/GenericTypeExtend.java
+++ /dev/null
@@ -1,137 +0,0 @@
-/*******************************************************************************
- * Copyright (c) 2010-2017, Zoltan Ujhelyi, IncQuery Labs Ltd.
- * Copyright (c) 2023 The Refinery Authors <https://refinery.tools/>
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Public License v. 2.0 which is available at
- * http://www.eclipse.org/legal/epl-v20.html.
- * SPDX-License-Identifier: EPL-2.0
- *******************************************************************************/
-package tools.refinery.store.query.viatra.internal.localsearch;
-
-import tools.refinery.viatra.runtime.localsearch.MatchingFrame;
-import tools.refinery.viatra.runtime.localsearch.matcher.ISearchContext;
-import tools.refinery.viatra.runtime.localsearch.operations.IIteratingSearchOperation;
-import tools.refinery.viatra.runtime.localsearch.operations.ISearchOperation;
-import tools.refinery.viatra.runtime.matchers.context.IInputKey;
-import tools.refinery.viatra.runtime.matchers.tuple.Tuple;
-import tools.refinery.viatra.runtime.matchers.tuple.TupleMask;
-import tools.refinery.viatra.runtime.matchers.tuple.VolatileMaskedTuple;
-import tools.refinery.viatra.runtime.matchers.util.Preconditions;
-
-import java.util.*;
-import java.util.function.Function;
-import java.util.stream.Collectors;
-
-/**
- * @author Zoltan Ujhelyi
- * @since 1.7
- */
-public class GenericTypeExtend implements IIteratingSearchOperation {
-    private class Executor extends ExtendOperationExecutor<Tuple> {
-        private final VolatileMaskedTuple maskedTuple;
-
-        public Executor() {
-            this.maskedTuple = new VolatileMaskedTuple(callMask);
-        }
-
-        @Override
-        protected Iterator<? extends Tuple> getIterator(MatchingFrame frame, ISearchContext context) {
-            maskedTuple.updateTuple(frame);
-            return context.getRuntimeContext().enumerateTuples(type, indexerMask, maskedTuple).iterator();
-        }
-
-        @Override
-        protected boolean fillInValue(Tuple newTuple, MatchingFrame frame, ISearchContext context) {
-            for (Integer position : unboundVariableIndices) {
-                frame.setValue(position, null);
-            }
-            for (int i = 0; i < positions.length; i++) {
-                Object newValue = newTuple.get(i);
-                Object oldValue = frame.getValue(positions[i]);
-                if (oldValue != null && !Objects.equals(oldValue, newValue)) {
-                    // If positions tuple maps more than one values for the same element (e.g. loop), it means that
-                    // these arguments are to unified by the caller. In this case if the callee assigns different values
-                    // the frame shall be considered a failed match
-                    return false;
-                }
-                frame.setValue(positions[i], newValue);
-            }
-            return true;
-        }
-
-        @Override
-        protected void cleanup(MatchingFrame frame, ISearchContext context) {
-            for (Integer position : unboundVariableIndices) {
-                frame.setValue(position, null);
-            }
-        }
-
-                @Override
-        public ISearchOperation getOperation() {
-            return GenericTypeExtend.this;
-        }
-    }
-
-    private final IInputKey type;
-    private final int[] positions;
-    private final List<Integer> positionList;
-    private final Set<Integer> unboundVariableIndices;
-    private final TupleMask indexerMask;
-    private final TupleMask callMask;
-
-    /**
-     *
-     * @param type
-     *            the type to execute the extend operation on
-     * @param positions
-     *            the parameter positions that represent the variables of the input key
-     * @param unboundVariableIndices
-     *            the set of positions that are bound at the start of the operation
-     */
-    public GenericTypeExtend(IInputKey type, int[] positions, TupleMask callMask, TupleMask indexerMask, Set<Integer> unboundVariableIndices) {
-        Preconditions.checkArgument(positions.length == type.getArity(),
-                "The type %s requires %d parameters, but %d positions are provided", type.getPrettyPrintableName(),
-                type.getArity(), positions.length);
-        List<Integer> modifiablePositionList = new ArrayList<>();
-        for (int position : positions) {
-            modifiablePositionList.add(position);
-        }
-        this.positionList = Collections.unmodifiableList(modifiablePositionList);
-        this.positions = positions;
-        this.type = type;
-
-        this.unboundVariableIndices = unboundVariableIndices;
-        this.indexerMask = indexerMask;
-        this.callMask = callMask;
-    }
-
-    @Override
-    public IInputKey getIteratedInputKey() {
-        return type;
-    }
-
-    @Override
-    public ISearchOperationExecutor createExecutor() {
-        return new Executor();
-    }
-
-    @Override
-    public List<Integer> getVariablePositions() {
-        return positionList;
-    }
-
-    @Override
-    public String toString() {
-        return toString(Object::toString);
-    }
-
-    @Override
-    public String toString(@SuppressWarnings("squid:S4276") Function<Integer, String> variableMapping) {
-        return "extend    " + type.getPrettyPrintableName() + "("
-                + positionList.stream()
-                        .map(input -> String.format("%s%s", unboundVariableIndices.contains(input) ? "-" : "+", variableMapping.apply(input)))
-                        .collect(Collectors.joining(", "))
-                + ")";
-    }
-
-}
diff --git a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/RelationalLocalSearchBackendFactory.java b/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/RelationalLocalSearchBackendFactory.java
deleted file mode 100644
index 7d5401c6..00000000
--- a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/RelationalLocalSearchBackendFactory.java
+++ /dev/null
@@ -1,60 +0,0 @@
-/*
- * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
- *
- * SPDX-License-Identifier: EPL-2.0
- */
-package tools.refinery.store.query.viatra.internal.localsearch;
-
-import tools.refinery.viatra.runtime.localsearch.matcher.integration.AbstractLocalSearchResultProvider;
-import tools.refinery.viatra.runtime.localsearch.matcher.integration.LocalSearchBackend;
-import tools.refinery.viatra.runtime.localsearch.matcher.integration.LocalSearchHints;
-import tools.refinery.viatra.runtime.localsearch.plan.IPlanProvider;
-import tools.refinery.viatra.runtime.localsearch.plan.SimplePlanProvider;
-import tools.refinery.viatra.runtime.matchers.backend.IMatcherCapability;
-import tools.refinery.viatra.runtime.matchers.backend.IQueryBackend;
-import tools.refinery.viatra.runtime.matchers.backend.IQueryBackendFactory;
-import tools.refinery.viatra.runtime.matchers.backend.QueryEvaluationHint;
-import tools.refinery.viatra.runtime.matchers.context.IQueryBackendContext;
-import tools.refinery.viatra.runtime.matchers.psystem.queries.PQuery;
-
-public class RelationalLocalSearchBackendFactory implements IQueryBackendFactory {
-        public static final RelationalLocalSearchBackendFactory INSTANCE = new RelationalLocalSearchBackendFactory();
-
-        private RelationalLocalSearchBackendFactory() {
-        }
-
-        @Override
-        public IQueryBackend create(IQueryBackendContext context) {
-                return new LocalSearchBackend(context) {
-                        // Create a new {@link IPlanProvider}, because the original {@link LocalSearchBackend#planProvider} is not
-                        // accessible.
-                        private final IPlanProvider planProvider = new SimplePlanProvider(context.getLogger());
-
-                        @Override
-                        protected AbstractLocalSearchResultProvider initializeResultProvider(PQuery query,
-                                                                                                                                                                 QueryEvaluationHint hints) {
-                                return new RelationalLocalSearchResultProvider(this, context, query, planProvider, hints);
-                        }
-
-                        @Override
-                        public IQueryBackendFactory getFactory() {
-                                return RelationalLocalSearchBackendFactory.this;
-                        }
-                };
-        }
-
-        @Override
-        public Class<? extends IQueryBackend> getBackendClass() {
-                return LocalSearchBackend.class;
-        }
-
-        @Override
-        public IMatcherCapability calculateRequiredCapability(PQuery pQuery, QueryEvaluationHint queryEvaluationHint) {
-                return LocalSearchHints.parse(queryEvaluationHint);
-        }
-
-        @Override
-        public boolean isCaching() {
-                return false;
-        }
-}
diff --git a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/RelationalLocalSearchResultProvider.java b/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/RelationalLocalSearchResultProvider.java
deleted file mode 100644
index 37d06864..00000000
--- a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/RelationalLocalSearchResultProvider.java
+++ /dev/null
@@ -1,28 +0,0 @@
-/*
- * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
- *
- * SPDX-License-Identifier: EPL-2.0
- */
-package tools.refinery.store.query.viatra.internal.localsearch;
-
-import tools.refinery.viatra.runtime.localsearch.matcher.integration.AbstractLocalSearchResultProvider;
-import tools.refinery.viatra.runtime.localsearch.matcher.integration.LocalSearchBackend;
-import tools.refinery.viatra.runtime.localsearch.matcher.integration.LocalSearchHints;
-import tools.refinery.viatra.runtime.localsearch.plan.IPlanProvider;
-import tools.refinery.viatra.runtime.localsearch.planner.compiler.IOperationCompiler;
-import tools.refinery.viatra.runtime.matchers.backend.QueryEvaluationHint;
-import tools.refinery.viatra.runtime.matchers.context.IQueryBackendContext;
-import tools.refinery.viatra.runtime.matchers.psystem.queries.PQuery;
-
-class RelationalLocalSearchResultProvider extends AbstractLocalSearchResultProvider {
-        public RelationalLocalSearchResultProvider(LocalSearchBackend backend, IQueryBackendContext context, PQuery query,
-                                                                                           IPlanProvider planProvider, QueryEvaluationHint userHints) {
-                super(backend, context, query, planProvider, userHints);
-        }
-
-        @Override
-        protected IOperationCompiler getOperationCompiler(IQueryBackendContext backendContext,
-                                                                                                          LocalSearchHints configuration) {
-                return new RelationalOperationCompiler(runtimeContext);
-        }
-}
diff --git a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/RelationalOperationCompiler.java b/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/RelationalOperationCompiler.java
deleted file mode 100644
index 37f264ae..00000000
--- a/subprojects/store-query-viatra/src/main/java/tools/refinery/store/query/viatra/internal/localsearch/RelationalOperationCompiler.java
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
- *
- * SPDX-License-Identifier: EPL-2.0
- */
-package tools.refinery.store.query.viatra.internal.localsearch;
-
-import tools.refinery.viatra.runtime.localsearch.operations.generic.GenericTypeExtendSingleValue;
-import tools.refinery.viatra.runtime.localsearch.operations.util.CallInformation;
-import tools.refinery.viatra.runtime.localsearch.planner.compiler.GenericOperationCompiler;
-import tools.refinery.viatra.runtime.matchers.context.IInputKey;
-import tools.refinery.viatra.runtime.matchers.context.IQueryRuntimeContext;
-import tools.refinery.viatra.runtime.matchers.psystem.PVariable;
-import tools.refinery.viatra.runtime.matchers.psystem.basicenumerables.PositivePatternCall;
-import tools.refinery.viatra.runtime.matchers.psystem.basicenumerables.TypeConstraint;
-import tools.refinery.viatra.runtime.matchers.tuple.Tuple;
-import tools.refinery.viatra.runtime.matchers.tuple.TupleMask;
-
-import java.util.*;
-
-public class RelationalOperationCompiler extends GenericOperationCompiler  {
-        public RelationalOperationCompiler(IQueryRuntimeContext runtimeContext) {
-                super(runtimeContext);
-        }
-
-        @Override
-        protected void createExtend(TypeConstraint typeConstraint, Map<PVariable, Integer> variableMapping) {
-                IInputKey inputKey = typeConstraint.getSupplierKey();
-                Tuple tuple = typeConstraint.getVariablesTuple();
-
-                int[] positions = new int[tuple.getSize()];
-                List<Integer> boundVariableIndices = new ArrayList<>();
-                List<Integer> boundVariables = new ArrayList<>();
-                Set<Integer> unboundVariables = new HashSet<>();
-                for (int i = 0; i < tuple.getSize(); i++) {
-                        PVariable variable = (PVariable) tuple.get(i);
-                        Integer position = variableMapping.get(variable);
-                        positions[i] = position;
-                        if (variableBindings.get(typeConstraint).contains(position)) {
-                                boundVariableIndices.add(i);
-                                boundVariables.add(position);
-                        } else {
-                                unboundVariables.add(position);
-                        }
-                }
-                TupleMask indexerMask = TupleMask.fromSelectedIndices(inputKey.getArity(), boundVariableIndices);
-                TupleMask callMask = TupleMask.fromSelectedIndices(variableMapping.size(), boundVariables);
-                // If multiple tuple elements from the indexer should be bound to the same variable, we must use a
-                // {@link GenericTypeExtend} check whether the tuple elements have the same value.
-                if (unboundVariables.size() == 1 && indexerMask.getSize() + 1 == indexerMask.getSourceWidth()) {
-                        operations.add(new GenericTypeExtendSingleValue(inputKey, positions, callMask, indexerMask,
-                                        unboundVariables.iterator().next()));
-                } else {
-                        // Use a fixed version of
-                        // {@code tools.refinery.viatra.runtime.localsearch.operations.generic.GenericTypeExtend} that handles
-                        // failed unification of variables correctly.
-                        operations.add(new GenericTypeExtend(inputKey, positions, callMask, indexerMask, unboundVariables));
-                }
-        }
-
-        @Override
-        protected void createExtend(PositivePatternCall pCall, Map<PVariable, Integer> variableMapping) {
-                CallInformation information = CallInformation.create(pCall, variableMapping, variableBindings.get(pCall));
-                // Use a fixed version of
-                // {@code tools.refinery.viatra.runtime.localsearch.operations.extend.ExtendPositivePatternCall} that handles
-                // failed unification of variables correctly.
-                operations.add(new ExtendPositivePatternCall(information));
-                dependencies.add(information.getCallWithAdornment());
-        }
-}
diff --git a/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/ExtendOperationExecutor.java b/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/ExtendOperationExecutor.java
index 01179118..a72c30dd 100644
--- a/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/ExtendOperationExecutor.java
+++ b/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/ExtendOperationExecutor.java
@@ -1,19 +1,20 @@
 /*******************************************************************************
  * Copyright (c) 2010-2013, Zoltan Ujhelyi, Akos Horvath, Istvan Rath and Daniel Varro
+ * Copyright (c) 2023 The Refinery Authors <https://refinery.tools/>
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
  * http://www.eclipse.org/legal/epl-v20.html.
- * 
+ *
  * SPDX-License-Identifier: EPL-2.0
  *******************************************************************************/
 package tools.refinery.viatra.runtime.localsearch.operations;
 
-import java.util.Iterator;
-
 import tools.refinery.viatra.runtime.localsearch.MatchingFrame;
 import tools.refinery.viatra.runtime.localsearch.matcher.ISearchContext;
 import tools.refinery.viatra.runtime.localsearch.operations.ISearchOperation.ISearchOperationExecutor;
 
+import java.util.Iterator;
+
 /**
  * An operation that can be used to enumerate all possible values for a single position based on a constraint
  * @author Zoltan Ujhelyi, Akos Horvath
@@ -31,42 +32,46 @@ public abstract class ExtendOperationExecutor<T> implements ISearchOperationExec
     protected abstract Iterator<? extends T> getIterator(MatchingFrame frame, ISearchContext context);
     /**
      * Updates the frame with the next element of the iterator. Called during {@link #execute(MatchingFrame, ISearchContext)}.
-     * 
+     *
      * @return true if the update is successful or false otherwise; in case of false is returned, the next element should be taken from the iterator.
      * @since 2.0
      */
     protected abstract boolean fillInValue(T newValue, MatchingFrame frame, ISearchContext context);
-    
+
     /**
      * Restores the frame to the state before {@link #fillInValue(Object, MatchingFrame, ISearchContext)}. Called during
      * {@link #onBacktrack(MatchingFrame, ISearchContext)}.
-     * 
+     *
      * @since 2.0
      */
     protected abstract void cleanup(MatchingFrame frame, ISearchContext context);
-    
+
     @Override
     public void onInitialize(MatchingFrame frame, ISearchContext context) {
         it = getIterator(frame, context);
     }
-    
+
     @Override
     public void onBacktrack(MatchingFrame frame, ISearchContext context) {
         it = null;
 
     }
 
-    @Override
-    public boolean execute(MatchingFrame frame, ISearchContext context) {
-        if (it.hasNext()){
-            T newValue = it.next();
-            while(!fillInValue(newValue, frame, context) && it.hasNext()){
-                newValue = it.next();
-            }
-            return true;
-        } else {
-            return false;
-        }
-    }
-    
+        /**
+         * Fixed version that handles failed unification of variables correctly.
+         * @param frame The matching frame to extend.
+         * @param context The search context.
+         * @return {@code true} if an extension was found, {@code false} otherwise.
+         */
+        @Override
+        public boolean execute(MatchingFrame frame, ISearchContext context) {
+                while (it.hasNext()) {
+                        var newValue = it.next();
+                        if (fillInValue(newValue, frame, context)) {
+                                return true;
+                        }
+                }
+                return false;
+        }
+
 }
diff --git a/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/planner/compiler/GenericOperationCompiler.java b/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/planner/compiler/GenericOperationCompiler.java
index 606048b7..d86982e9 100644
--- a/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/planner/compiler/GenericOperationCompiler.java
+++ b/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/planner/compiler/GenericOperationCompiler.java
@@ -1,19 +1,14 @@
 /*******************************************************************************
  * Copyright (c) 2010-2017, Zoltan Ujhelyi, IncQuery Labs Ltd.
+ * Copyright (c) 2023 The Refinery Authors <https://refinery.tools/>
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
  * http://www.eclipse.org/legal/epl-v20.html.
- * 
+ *
  * SPDX-License-Identifier: EPL-2.0
  *******************************************************************************/
 package tools.refinery.viatra.runtime.localsearch.planner.compiler;
 
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-
 import tools.refinery.viatra.runtime.localsearch.operations.generic.GenericTypeCheck;
 import tools.refinery.viatra.runtime.localsearch.operations.generic.GenericTypeExtend;
 import tools.refinery.viatra.runtime.localsearch.operations.generic.GenericTypeExtendSingleValue;
@@ -25,6 +20,8 @@ import tools.refinery.viatra.runtime.matchers.psystem.basicenumerables.TypeConst
 import tools.refinery.viatra.runtime.matchers.tuple.Tuple;
 import tools.refinery.viatra.runtime.matchers.tuple.TupleMask;
 
+import java.util.*;
+
 /**
  * @author Zoltan Ujhelyi
  * @since 1.7
@@ -46,9 +43,9 @@ public class GenericOperationCompiler extends AbstractOperationCompiler {
             positions[i] = variableMapping.get(variable);
         }
         operations.add(new GenericTypeCheck(inputKey, positions, TupleMask.fromSelectedIndices(variableMapping.size(), positions)));
-        
+
     }
-    
+
     @Override
     protected void createCheck(TypeConstraint typeConstraint, Map<PVariable, Integer> variableMapping) {
         IInputKey inputKey = typeConstraint.getSupplierKey();
@@ -60,7 +57,7 @@ public class GenericOperationCompiler extends AbstractOperationCompiler {
         }
         operations.add(new GenericTypeCheck(inputKey, positions, TupleMask.fromSelectedIndices(variableMapping.size(), positions)));
     }
-    
+
     @Override
     protected void createUnaryTypeCheck(IInputKey inputKey, int position) {
         int[] positions = new int[] {position};
@@ -71,7 +68,7 @@ public class GenericOperationCompiler extends AbstractOperationCompiler {
     protected void createExtend(TypeConstraint typeConstraint, Map<PVariable, Integer> variableMapping) {
         IInputKey inputKey = typeConstraint.getSupplierKey();
         Tuple tuple = typeConstraint.getVariablesTuple();
-        
+
         int[] positions = new int[tuple.getSize()];
         List<Integer> boundVariableIndices = new ArrayList<>();
         List<Integer> boundVariables = new ArrayList<>();
@@ -89,7 +86,9 @@ public class GenericOperationCompiler extends AbstractOperationCompiler {
         }
         TupleMask indexerMask = TupleMask.fromSelectedIndices(inputKey.getArity(), boundVariableIndices);
         TupleMask callMask = TupleMask.fromSelectedIndices(variableMapping.size(), boundVariables);
-        if (unboundVariables.size() == 1) {
+                // If multiple tuple elements from the indexer should be bound to the same variable, we must use a
+                // {@link GenericTypeExtend} check whether the tuple elements have the same value.
+                if (unboundVariables.size() == 1 && indexerMask.getSize() + 1 == indexerMask.getSourceWidth()) {
             operations.add(new GenericTypeExtendSingleValue(inputKey, positions, callMask, indexerMask, unboundVariables.iterator().next()));
         } else {
             operations.add(new GenericTypeExtend(inputKey, positions, callMask, indexerMask, unboundVariables));