CompletionSuggestionContext#toQuery() should also consider text if prefix/regex missing (#23451)

In cases where the user specifies only the `text` option on the top level
suggest element (either via REST or the java api), this gets transferred to the
`text` property in the SuggestionSearchContext. CompletionSuggestionContext
currently requires prefix or regex to be specified, otherwise errors. We should
use the global `text` property as a fallback if neither prefix nor regex is provided.

Closes to #23340

2 files changed, 52 insertions, 15 deletions

diff --git a/core/src/main/java/org/elasticsearch/search/suggest/completion/CompletionSuggestionContext.java b/core/src/main/java/org/elasticsearch/search/suggest/completion/CompletionSuggestionContext.java
index a4aeec8cb5..b12b90de10 100644
--- a/core/src/main/java/org/elasticsearch/search/suggest/completion/CompletionSuggestionContext.java
+++ b/core/src/main/java/org/elasticsearch/search/suggest/completion/CompletionSuggestionContext.java
@@ -19,6 +19,7 @@
 package org.elasticsearch.search.suggest.completion;
 
 import org.apache.lucene.search.suggest.document.CompletionQuery;
+import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.unit.Fuzziness;
 import org.elasticsearch.index.mapper.CompletionFieldMapper;
 import org.elasticsearch.index.query.QueryShardContext;
@@ -77,15 +78,7 @@ public class CompletionSuggestionContext extends SuggestionSearchContext.Suggest
         CompletionFieldMapper.CompletionFieldType fieldType = getFieldType();
         final CompletionQuery query;
         if (getPrefix() != null) {
-            if (fuzzyOptions != null) {
-                query = fieldType.fuzzyQuery(getPrefix().utf8ToString(),
-                        Fuzziness.fromEdits(fuzzyOptions.getEditDistance()),
-                        fuzzyOptions.getFuzzyPrefixLength(), fuzzyOptions.getFuzzyMinLength(),
-                        fuzzyOptions.getMaxDeterminizedStates(), fuzzyOptions.isTranspositions(),
-                        fuzzyOptions.isUnicodeAware());
-            } else {
-                query = fieldType.prefixQuery(getPrefix());
-            }
+            query = createCompletionQuery(getPrefix(), fieldType);
         } else if (getRegex() != null) {
             if (fuzzyOptions != null) {
                 throw new IllegalArgumentException("can not use 'fuzzy' options with 'regex");
@@ -95,8 +88,10 @@ public class CompletionSuggestionContext extends SuggestionSearchContext.Suggest
             }
             query = fieldType.regexpQuery(getRegex(), regexOptions.getFlagsValue(),
                     regexOptions.getMaxDeterminizedStates());
+        } else if (getText() != null) {
+            query = createCompletionQuery(getText(), fieldType);
         } else {
-            throw new IllegalArgumentException("'prefix' or 'regex' must be defined");
+            throw new IllegalArgumentException("'prefix/text' or 'regex' must be defined");
         }
         if (fieldType.hasContextMappings()) {
             ContextMappings contextMappings = fieldType.getContextMappings();
@@ -105,4 +100,18 @@ public class CompletionSuggestionContext extends SuggestionSearchContext.Suggest
         return query;
     }
 
+    private CompletionQuery createCompletionQuery(BytesRef prefix, CompletionFieldMapper.CompletionFieldType fieldType) {
+        final CompletionQuery query;
+        if (fuzzyOptions != null) {
+            query = fieldType.fuzzyQuery(prefix.utf8ToString(),
+                    Fuzziness.fromEdits(fuzzyOptions.getEditDistance()),
+                    fuzzyOptions.getFuzzyPrefixLength(), fuzzyOptions.getFuzzyMinLength(),
+                    fuzzyOptions.getMaxDeterminizedStates(), fuzzyOptions.isTranspositions(),
+                    fuzzyOptions.isUnicodeAware());
+        } else {
+            query = fieldType.prefixQuery(prefix);
+        }
+        return query;
+    }
+
 }
diff --git a/core/src/test/java/org/elasticsearch/search/suggest/CompletionSuggestSearchIT.java b/core/src/test/java/org/elasticsearch/search/suggest/CompletionSuggestSearchIT.java
index 07502ff338..5bd2bad31d 100644
--- a/core/src/test/java/org/elasticsearch/search/suggest/CompletionSuggestSearchIT.java
+++ b/core/src/test/java/org/elasticsearch/search/suggest/CompletionSuggestSearchIT.java
@@ -68,12 +68,10 @@ import static org.elasticsearch.common.util.CollectionUtils.iterableAsArrayList;
 import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAllSuccessful;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertNoFailures;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertSearchHit;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.hasId;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.hasScore;
 import static org.hamcrest.Matchers.contains;
-import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
@@ -116,6 +114,36 @@ public class CompletionSuggestSearchIT extends ESIntegTestCase {
         assertSuggestions("foo", prefix, "suggestion10", "suggestion9", "suggestion8", "suggestion7", "suggestion6");
     }
 
+    /**
+     * test that suggestion works if prefix is either provided via {@link CompletionSuggestionBuilder#text(String)} or
+     * {@link SuggestBuilder#setGlobalText(String)}
+     */
+    public void testTextAndGlobalText() throws Exception {
+        final CompletionMappingBuilder mapping = new CompletionMappingBuilder();
+        createIndexAndMapping(mapping);
+        int numDocs = 10;
+        List<IndexRequestBuilder> indexRequestBuilders = new ArrayList<>();
+        for (int i = 1; i <= numDocs; i++) {
+            indexRequestBuilders.add(client().prepareIndex(INDEX, TYPE, "" + i).setSource(jsonBuilder().startObject().startObject(FIELD)
+                    .field("input", "suggestion" + i).field("weight", i).endObject().endObject()));
+        }
+        indexRandom(true, indexRequestBuilders);
+        CompletionSuggestionBuilder noText = SuggestBuilders.completionSuggestion(FIELD);
+        SearchResponse searchResponse = client().prepareSearch(INDEX)
+                .suggest(new SuggestBuilder().addSuggestion("foo", noText).setGlobalText("sugg")).execute().actionGet();
+        assertSuggestions(searchResponse, "foo", "suggestion10", "suggestion9", "suggestion8", "suggestion7", "suggestion6");
+
+        CompletionSuggestionBuilder withText = SuggestBuilders.completionSuggestion(FIELD).text("sugg");
+        searchResponse = client().prepareSearch(INDEX)
+                .suggest(new SuggestBuilder().addSuggestion("foo", withText)).execute().actionGet();
+        assertSuggestions(searchResponse, "foo", "suggestion10", "suggestion9", "suggestion8", "suggestion7", "suggestion6");
+
+        // test that suggestion text takes precedence over global text
+        searchResponse = client().prepareSearch(INDEX)
+                .suggest(new SuggestBuilder().addSuggestion("foo", withText).setGlobalText("bogus")).execute().actionGet();
+        assertSuggestions(searchResponse, "foo", "suggestion10", "suggestion9", "suggestion8", "suggestion7", "suggestion6");
+    }
+
     public void testRegex() throws Exception {
         final CompletionMappingBuilder mapping = new CompletionMappingBuilder();
         createIndexAndMapping(mapping);
@@ -217,7 +245,7 @@ public class CompletionSuggestSearchIT extends ESIntegTestCase {
         for (CompletionSuggestion.Entry.Option option : options) {
             assertThat(option.getText().toString(), equalTo("suggestion" + id));
             assertSearchHit(option.getHit(), hasId("" + id));
-            assertSearchHit(option.getHit(), hasScore(((float) id)));
+            assertSearchHit(option.getHit(), hasScore((id)));
             assertNotNull(option.getHit().getSourceAsMap());
             id--;
         }
@@ -252,7 +280,7 @@ public class CompletionSuggestSearchIT extends ESIntegTestCase {
         for (CompletionSuggestion.Entry.Option option : options) {
             assertThat(option.getText().toString(), equalTo("suggestion" + id));
             assertSearchHit(option.getHit(), hasId("" + id));
-            assertSearchHit(option.getHit(), hasScore(((float) id)));
+            assertSearchHit(option.getHit(), hasScore((id)));
             assertNull(option.getHit().getSourceAsMap());
             id--;
         }
@@ -289,7 +317,7 @@ public class CompletionSuggestSearchIT extends ESIntegTestCase {
         for (CompletionSuggestion.Entry.Option option : options) {
             assertThat(option.getText().toString(), equalTo("suggestion" + id));
             assertSearchHit(option.getHit(), hasId("" + id));
-            assertSearchHit(option.getHit(), hasScore(((float) id)));
+            assertSearchHit(option.getHit(), hasScore((id)));
             assertNotNull(option.getHit().getSourceAsMap());
             Set<String> sourceFields = option.getHit().getSourceAsMap().keySet();
             assertThat(sourceFields, contains("a"));