LUCENE-10412: Improve handling of MatchNoDocsQuery in rewrites. (#664)

lucene/CHANGES.txt

@@ -204,6 +204,9 @@ Optimizations
 * LUCENE-10367: Optimize CoveringQuery for the case when the minimum number of
   matching clauses is a constant. (LuYunCheng via Adrien Grand)
 
+* LUCENE-10412: More `Query#rewrite` optimizations for MatchNoDocsQuery.
+  (Adrien Grand)
+
 Changes in runtime behavior
 ---------------------
 

lucene/core/src/java/org/apache/lucene/search/BooleanQuery.java

@@ -275,10 +275,22 @@ public class BooleanQuery extends Query implements Iterable<BooleanClause> {
       for (BooleanClause clause : this) {
         Query query = clause.getQuery();
         Query rewritten = query.rewrite(reader);
-        if (rewritten != query) {
+        if (rewritten != query || query.getClass() == MatchNoDocsQuery.class) {
           // rewrite clause
           actuallyRewritten = true;
+          if (rewritten.getClass() == MatchNoDocsQuery.class) {
+            switch (clause.getOccur()) {
+              case SHOULD:
+              case MUST_NOT:
+                // the clause can be safely ignored
+                break;
+              case MUST:
+              case FILTER:
+                return rewritten;
+            }
+          } else {
             builder.add(rewritten, clause.getOccur());
+          }
         } else {
           // leave as-is
           builder.add(clause);

lucene/core/src/java/org/apache/lucene/search/BoostQuery.java

@@ -85,6 +85,11 @@ public final class BoostQuery extends Query {
       return new BoostQuery(in.query, boost * in.boost);
     }
 
+    if (rewritten.getClass() == MatchNoDocsQuery.class) {
+      // bubble up MatchNoDocsQuery
+      return rewritten;
+    }
+
     if (boost == 0f && rewritten.getClass() != ConstantScoreQuery.class) {
       // so that we pass needScores=false
       return new BoostQuery(new ConstantScoreQuery(rewritten), 0f);

lucene/core/src/java/org/apache/lucene/search/ConstantScoreQuery.java

@@ -43,6 +43,11 @@ public final class ConstantScoreQuery extends Query {
   public Query rewrite(IndexReader reader) throws IOException {
     Query rewritten = query.rewrite(reader);
 
+    if (rewritten.getClass() == MatchNoDocsQuery.class) {
+      // bubble up MatchNoDocsQuery
+      return rewritten;
+    }
+
     if (rewritten != query) {
       return new ConstantScoreQuery(rewritten);
     }

lucene/core/src/test/org/apache/lucene/search/TestBooleanRewrites.java

@@ -663,4 +663,54 @@ public class TestBooleanRewrites extends LuceneTestCase {
     w.close();
     dir.close();
   }
+
+  public void testShouldMatchNoDocsQuery() throws IOException {
+    IndexSearcher searcher = newSearcher(new MultiReader());
+
+    BooleanQuery query =
+        new BooleanQuery.Builder()
+            .add(new TermQuery(new Term("foo", "bar")), Occur.SHOULD)
+            .add(new MatchNoDocsQuery(), Occur.SHOULD)
+            .build();
+    assertEquals(new TermQuery(new Term("foo", "bar")), searcher.rewrite(query));
+  }
+
+  public void testMustNotMatchNoDocsQuery() throws IOException {
+    IndexSearcher searcher = newSearcher(new MultiReader());
+
+    BooleanQuery query =
+        new BooleanQuery.Builder()
+            .add(new TermQuery(new Term("foo", "bar")), Occur.SHOULD)
+            .add(new MatchNoDocsQuery(), Occur.MUST_NOT)
+            .build();
+    assertEquals(new TermQuery(new Term("foo", "bar")), searcher.rewrite(query));
+  }
+
+  public void testMustMatchNoDocsQuery() throws IOException {
+    IndexSearcher searcher = newSearcher(new MultiReader());
+
+    BooleanQuery query =
+        new BooleanQuery.Builder()
+            .add(new TermQuery(new Term("foo", "bar")), Occur.MUST)
+            .add(new MatchNoDocsQuery(), Occur.MUST)
+            .build();
+    assertEquals(new MatchNoDocsQuery(), searcher.rewrite(query));
+  }
+
+  public void testFilterMatchNoDocsQuery() throws IOException {
+    IndexSearcher searcher = newSearcher(new MultiReader());
+
+    BooleanQuery query =
+        new BooleanQuery.Builder()
+            .add(new TermQuery(new Term("foo", "bar")), Occur.MUST)
+            .add(new MatchNoDocsQuery(), Occur.FILTER)
+            .build();
+    assertEquals(new MatchNoDocsQuery(), searcher.rewrite(query));
+  }
+
+  public void testEmptyBoolean() throws IOException {
+    IndexSearcher searcher = newSearcher(new MultiReader());
+    BooleanQuery query = new BooleanQuery.Builder().build();
+    assertEquals(new MatchNoDocsQuery(), searcher.rewrite(query));
+  }
 }

lucene/core/src/test/org/apache/lucene/search/TestBoostQuery.java

@@ -73,8 +73,8 @@ public class TestBoostQuery extends LuceneTestCase {
     IndexSearcher searcher = new IndexSearcher(new MultiReader());
 
     // inner queries are rewritten
-    Query q = new BoostQuery(new BooleanQuery.Builder().build(), 2);
-    assertEquals(new BoostQuery(new MatchNoDocsQuery(), 2), searcher.rewrite(q));
+    Query q = new BoostQuery(new PhraseQuery("foo", "bar"), 2);
+    assertEquals(new BoostQuery(new TermQuery(new Term("foo", "bar")), 2), searcher.rewrite(q));
 
     // boosts are merged
     q = new BoostQuery(new BoostQuery(new MatchAllDocsQuery(), 3), 2);
@@ -85,4 +85,11 @@ public class TestBoostQuery extends LuceneTestCase {
     assertEquals(
         new BoostQuery(new ConstantScoreQuery(new MatchAllDocsQuery()), 0), searcher.rewrite(q));
   }
+
+  public void testRewriteBubblesUpMatchNoDocsQuery() throws IOException {
+    IndexSearcher searcher = newSearcher(new MultiReader());
+
+    Query query = new BoostQuery(new MatchNoDocsQuery(), 2f);
+    assertEquals(new MatchNoDocsQuery(), searcher.rewrite(query));
+  }
 }

lucene/core/src/test/org/apache/lucene/search/TestConstantScoreQuery.java

@@ -23,6 +23,7 @@ import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.MultiReader;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.store.Directory;
@@ -254,4 +255,11 @@ public class TestConstantScoreQuery extends LuceneTestCase {
     w.close();
     dir.close();
   }
+
+  public void testRewriteBubblesUpMatchNoDocsQuery() throws IOException {
+    IndexSearcher searcher = newSearcher(new MultiReader());
+
+    Query query = new ConstantScoreQuery(new MatchNoDocsQuery());
+    assertEquals(new MatchNoDocsQuery(), searcher.rewrite(query));
+  }
 }

lucene/core/src/test/org/apache/lucene/search/TestMatchNoDocsQuery.java

@@ -89,7 +89,7 @@ public class TestMatchNoDocsQuery extends LuceneTestCase {
     hits = searcher.search(query, 1000).scoreDocs;
     Query rewrite = query.rewrite(ir);
     assertEquals(1, hits.length);
-    assertEquals(rewrite.toString(), "key:one MatchNoDocsQuery(\"field not found\")");
+    assertEquals(rewrite.toString(), "key:one");
 
     iw.close();
     ir.close();