Prevent flattening of ordered and unordered interval sources

docs/changelog/114234.yaml

@@ -0,0 +1,5 @@
+pr: 114234
+summary: Prevent flattening of ordered and unordered interval sources
+area: Search
+type: bug
+issues: []

server/src/internalClusterTest/java/org/elasticsearch/search/query/IntervalQueriesIT.java

@@ -31,6 +31,7 @@
 import static java.util.Collections.singletonMap;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertNoFailures;
+import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertSearchHits;
 
 public class IntervalQueriesIT extends ESIntegTestCase {
 
@@ -64,6 +65,58 @@ public void testEmptyIntervalsWithNestedMappings() throws InterruptedException {
         );
     }
 
+    public void testPreserveInnerGap() {
+        assertAcked(prepareCreate("index").setMapping("""
+            {
+                "_doc" : {
+                    "properties" : {
+                        "text" : { "type" : "text" }
+                    }
+                }
+            }
+            """));
+
+        indexRandom(true, prepareIndex("index").setId("1").setSource("text", "w1 w2 w3 w4 w5"));
+
+        // ordered
+        {
+            var res = prepareSearch("index").setQuery(
+                new IntervalQueryBuilder(
+                    "text",
+                    new IntervalsSourceProvider.Combine(
+                        Arrays.asList(
+                            new IntervalsSourceProvider.Match("w1 w4", -1, true, null, null, null),
+                            new IntervalsSourceProvider.Match("w5", -1, true, null, null, null)
+                        ),
+                        true,
+                        1,
+                        null
+                    )
+                )
+            );
+            assertSearchHits(res, "1");
+        }
+
+        // unordered
+        {
+            var res = prepareSearch("index").setQuery(
+                new IntervalQueryBuilder(
+                    "text",
+                    new IntervalsSourceProvider.Combine(
+                        Arrays.asList(
+                            new IntervalsSourceProvider.Match("w3", 0, false, null, null, null),
+                            new IntervalsSourceProvider.Match("w4 w1", -1, false, null, null, null)
+                        ),
+                        false,
+                        0,
+                        null
+                    )
+                )
+            );
+            assertSearchHits(res, "1");
+        }
+    }
+
     private static class EmptyAnalyzer extends Analyzer {
 
         @Override

server/src/main/java/org/elasticsearch/index/query/IntervalBuilder.java

@@ -126,7 +126,7 @@ protected static IntervalsSource combineSources(List<IntervalsSource> sources, i
         if (maxGaps == 0 && ordered) {
             return Intervals.phrase(sourcesArray);
         }
-        IntervalsSource inner = ordered ? Intervals.ordered(sourcesArray) : Intervals.unordered(sourcesArray);
+        IntervalsSource inner = ordered ? XIntervals.ordered(sourcesArray) : XIntervals.unordered(sourcesArray);
         if (maxGaps == -1) {
             return inner;
         }

server/src/main/java/org/elasticsearch/index/query/XIntervals.java

@@ -0,0 +1,106 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.index.query;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.queries.intervals.IntervalIterator;
+import org.apache.lucene.queries.intervals.IntervalMatchesIterator;
+import org.apache.lucene.queries.intervals.Intervals;
+import org.apache.lucene.queries.intervals.IntervalsSource;
+import org.apache.lucene.search.QueryVisitor;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Objects;
+
+/**
+ * Copy of {@link Intervals} that exposes versions of {@link Intervals#ordered} and {@link Intervals#unordered}
+ * that preserve their inner gaps.
+ * NOTE: Remove this hack when a version of Lucene with https://github.com/apache/lucene/pull/13819 is used (10.1.0).
+ */
+public final class XIntervals {
+
+    /**
+     * Create an ordered {@link IntervalsSource}
+     *
+     * <p>Returns intervals in which the subsources all appear in the given order
+     *
+     * @param subSources an ordered set of {@link IntervalsSource} objects
+     */
+    public static IntervalsSource ordered(IntervalsSource... subSources) {
+        return new DelegateIntervalsSource(Intervals.ordered(subSources));
+    }
+
+    /**
+     * Create an ordered {@link IntervalsSource}
+     *
+     * <p>Returns intervals in which the subsources all appear in the given order
+     *
+     * @param subSources an ordered set of {@link IntervalsSource} objects
+     */
+    public static IntervalsSource unordered(IntervalsSource... subSources) {
+        return new DelegateIntervalsSource(Intervals.unordered(subSources));
+    }
+
+    /**
+     * Wraps a source to avoid aggressive flattening of the ordered and unordered sources.
+     * The flattening modifies the final gap and is removed in the latest unreleased version of Lucene (10.1).
+     */
+    private static class DelegateIntervalsSource extends IntervalsSource {
+        private final IntervalsSource delegate;
+
+        private DelegateIntervalsSource(IntervalsSource delegate) {
+            this.delegate = delegate;
+        }
+
+        @Override
+        public IntervalIterator intervals(String field, LeafReaderContext ctx) throws IOException {
+            return delegate.intervals(field, ctx);
+        }
+
+        @Override
+        public IntervalMatchesIterator matches(String field, LeafReaderContext ctx, int doc) throws IOException {
+            return delegate.matches(field, ctx, doc);
+        }
+
+        @Override
+        public void visit(String field, QueryVisitor visitor) {
+            delegate.visit(field, visitor);
+        }
+
+        @Override
+        public int minExtent() {
+            return delegate.minExtent();
+        }
+
+        @Override
+        public Collection<IntervalsSource> pullUpDisjunctions() {
+            return delegate.pullUpDisjunctions();
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            DelegateIntervalsSource that = (DelegateIntervalsSource) o;
+            return Objects.equals(delegate, that.delegate);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(delegate);
+        }
+
+        @Override
+        public String toString() {
+            return delegate.toString();
+        }
+    }
+}

server/src/test/java/org/elasticsearch/index/query/IntervalBuilderTests.java

@@ -46,7 +46,7 @@ public void testOrdered() throws IOException {
         CannedTokenStream ts = new CannedTokenStream(new Token("term1", 1, 2), new Token("term2", 3, 4), new Token("term3", 5, 6));
 
         IntervalsSource source = BUILDER.analyzeText(new CachingTokenFilter(ts), -1, true);
-        IntervalsSource expected = Intervals.ordered(Intervals.term("term1"), Intervals.term("term2"), Intervals.term("term3"));
+        IntervalsSource expected = XIntervals.ordered(Intervals.term("term1"), Intervals.term("term2"), Intervals.term("term3"));
 
         assertEquals(expected, source);
 
@@ -57,7 +57,7 @@ public void testUnordered() throws IOException {
         CannedTokenStream ts = new CannedTokenStream(new Token("term1", 1, 2), new Token("term2", 3, 4), new Token("term3", 5, 6));
 
         IntervalsSource source = BUILDER.analyzeText(new CachingTokenFilter(ts), -1, false);
-        IntervalsSource expected = Intervals.unordered(Intervals.term("term1"), Intervals.term("term2"), Intervals.term("term3"));
+        IntervalsSource expected = XIntervals.unordered(Intervals.term("term1"), Intervals.term("term2"), Intervals.term("term3"));
 
         assertEquals(expected, source);
 
@@ -101,7 +101,7 @@ public void testSimpleSynonyms() throws IOException {
         );
 
         IntervalsSource source = BUILDER.analyzeText(new CachingTokenFilter(ts), -1, true);
-        IntervalsSource expected = Intervals.ordered(
+        IntervalsSource expected = XIntervals.ordered(
             Intervals.term("term1"),
             Intervals.or(Intervals.term("term2"), Intervals.term("term4")),
             Intervals.term("term3")
@@ -122,7 +122,7 @@ public void testSimpleSynonymsWithGap() throws IOException {
         );
 
         IntervalsSource source = BUILDER.analyzeText(new CachingTokenFilter(ts), -1, true);
-        IntervalsSource expected = Intervals.ordered(
+        IntervalsSource expected = XIntervals.ordered(
             Intervals.term("term1"),
             Intervals.extend(Intervals.or(Intervals.term("term2"), Intervals.term("term3"), Intervals.term("term4")), 1, 0),
             Intervals.term("term5")
@@ -143,7 +143,7 @@ public void testGraphSynonyms() throws IOException {
         );
 
         IntervalsSource source = BUILDER.analyzeText(new CachingTokenFilter(ts), -1, true);
-        IntervalsSource expected = Intervals.ordered(
+        IntervalsSource expected = XIntervals.ordered(
             Intervals.term("term1"),
             Intervals.or(Intervals.term("term2"), Intervals.phrase("term3", "term4")),
             Intervals.term("term5")
@@ -166,7 +166,7 @@ public void testGraphSynonymsWithGaps() throws IOException {
         );
 
         IntervalsSource source = BUILDER.analyzeText(new CachingTokenFilter(ts), -1, true);
-        IntervalsSource expected = Intervals.ordered(
+        IntervalsSource expected = XIntervals.ordered(
             Intervals.term("term1"),
             Intervals.or(
                 Intervals.extend(Intervals.term("term2"), 1, 0),
@@ -190,7 +190,7 @@ public void testGraphTerminatesOnGap() throws IOException {
         );
 
         IntervalsSource source = BUILDER.analyzeText(new CachingTokenFilter(ts), -1, true);
-        IntervalsSource expected = Intervals.ordered(
+        IntervalsSource expected = XIntervals.ordered(
             Intervals.term("term1"),
             Intervals.or(Intervals.term("term2"), Intervals.phrase("term3", "term4")),
             Intervals.extend(Intervals.term("term5"), 1, 0)

server/src/test/java/org/elasticsearch/index/query/IntervalQueryBuilderTests.java

@@ -203,7 +203,7 @@ public void testMatchInterval() throws IOException {
             }""", TEXT_FIELD_NAME);
 
         IntervalQueryBuilder builder = (IntervalQueryBuilder) parseQuery(json);
-        Query expected = new IntervalQuery(TEXT_FIELD_NAME, Intervals.unordered(Intervals.term("hello"), Intervals.term("world")));
+        Query expected = new IntervalQuery(TEXT_FIELD_NAME, XIntervals.unordered(Intervals.term("hello"), Intervals.term("world")));
 
         assertEquals(expected, builder.toQuery(createSearchExecutionContext()));
 
@@ -222,7 +222,7 @@ public void testMatchInterval() throws IOException {
         builder = (IntervalQueryBuilder) parseQuery(json);
         expected = new IntervalQuery(
             TEXT_FIELD_NAME,
-            Intervals.maxgaps(40, Intervals.unordered(Intervals.term("hello"), Intervals.term("world")))
+            Intervals.maxgaps(40, XIntervals.unordered(Intervals.term("hello"), Intervals.term("world")))
         );
         assertEquals(expected, builder.toQuery(createSearchExecutionContext()));
 
@@ -241,7 +241,7 @@ public void testMatchInterval() throws IOException {
 
         builder = (IntervalQueryBuilder) parseQuery(json);
         expected = new BoostQuery(
-            new IntervalQuery(TEXT_FIELD_NAME, Intervals.ordered(Intervals.term("hello"), Intervals.term("world"))),
+            new IntervalQuery(TEXT_FIELD_NAME, XIntervals.ordered(Intervals.term("hello"), Intervals.term("world"))),
             2
         );
         assertEquals(expected, builder.toQuery(createSearchExecutionContext()));
@@ -263,7 +263,7 @@ public void testMatchInterval() throws IOException {
         builder = (IntervalQueryBuilder) parseQuery(json);
         expected = new IntervalQuery(
             TEXT_FIELD_NAME,
-            Intervals.maxgaps(10, Intervals.ordered(Intervals.term("Hello"), Intervals.term("world")))
+            Intervals.maxgaps(10, XIntervals.ordered(Intervals.term("Hello"), Intervals.term("world")))
         );
         assertEquals(expected, builder.toQuery(createSearchExecutionContext()));
 
@@ -285,7 +285,7 @@ public void testMatchInterval() throws IOException {
         builder = (IntervalQueryBuilder) parseQuery(json);
         expected = new IntervalQuery(
             TEXT_FIELD_NAME,
-            Intervals.fixField(MASKED_FIELD, Intervals.maxgaps(10, Intervals.ordered(Intervals.term("Hello"), Intervals.term("world"))))
+            Intervals.fixField(MASKED_FIELD, Intervals.maxgaps(10, XIntervals.ordered(Intervals.term("Hello"), Intervals.term("world"))))
         );
         assertEquals(expected, builder.toQuery(createSearchExecutionContext()));
 
@@ -314,7 +314,7 @@ public void testMatchInterval() throws IOException {
         expected = new IntervalQuery(
             TEXT_FIELD_NAME,
             Intervals.containing(
-                Intervals.maxgaps(10, Intervals.ordered(Intervals.term("Hello"), Intervals.term("world"))),
+                Intervals.maxgaps(10, XIntervals.ordered(Intervals.term("Hello"), Intervals.term("world"))),
                 Intervals.term("blah")
             )
         );
@@ -426,7 +426,7 @@ public void testCombineInterval() throws IOException {
                 Intervals.containedBy(
                     Intervals.maxgaps(
                         30,
-                        Intervals.ordered(Intervals.term("one"), Intervals.unordered(Intervals.term("two"), Intervals.term("three")))
+                        XIntervals.ordered(Intervals.term("one"), XIntervals.unordered(Intervals.term("two"), Intervals.term("three")))
                     ),
                     Intervals.term("SENTENCE")
                 )
@@ -486,7 +486,7 @@ public void testCombineDisjunctionInterval() throws IOException {
             Intervals.notContainedBy(
                 Intervals.maxgaps(
                     30,
-                    Intervals.ordered(Intervals.term("atmosphere"), Intervals.or(Intervals.term("cold"), Intervals.term("outside")))
+                    XIntervals.ordered(Intervals.term("atmosphere"), Intervals.or(Intervals.term("cold"), Intervals.term("outside")))
                 ),
                 Intervals.term("freeze")
             )