Add test

Author: svilen-mihaylov-elastic

server/src/internalClusterTest/java/org/elasticsearch/search/fetch/subphase/highlight/HighlighterSearchIT.java

@@ -2632,6 +2632,42 @@ public void testPostingsHighlighterOrderByScore() throws Exception {
         });
     }
 
+    public void testMaxQueryOffsetDefault() throws Exception {
+        assertAcked(
+            prepareCreate("test").setMapping(type1PostingsffsetsMapping())
+                .setSettings(Settings.builder().put("index.highlight.max_analyzed_offset", "10").build())
+        );
+        ensureGreen();
+
+        prepareIndex("test").setSource(
+            "field1",
+            new String[] {
+                "This sentence contains one match, not that short. This sentence contains zero sentence matches. "
+                    + "This one contains no matches.",
+                "This is the second value's first sentence. This one contains no matches. "
+                    + "This sentence contains three sentence occurrences (sentence).",
+                "One sentence match here and scored lower since the text is quite long, not that appealing. "
+                    + "This one contains no matches." }
+        ).get();
+        refresh();
+
+        logger.info("--> highlighting and searching on field1");
+        // Specific for this test: by passing "-1" as "maxAnalyzedOffset", the index highlight setting above will be used.
+        SearchSourceBuilder source = searchSource().query(termQuery("field1", "sentence"))
+            .highlighter(highlight().field("field1").order("score").maxAnalyzedOffset(-1));
+
+        assertResponse(client().search(new SearchRequest("test").source(source)), response -> {
+            Map<String, HighlightField> highlightFieldMap = response.getHits().getAt(0).getHighlightFields();
+            assertThat(highlightFieldMap.size(), equalTo(1));
+            HighlightField field1 = highlightFieldMap.get("field1");
+            assertThat(field1.fragments().length, equalTo(1));
+            assertThat(
+                field1.fragments()[0].string(),
+                equalTo("This <em>sentence</em> contains one match, not that short. This sentence contains zero sentence matches.")
+            );
+        });
+    }
+
     public void testPostingsHighlighterEscapeHtml() throws Exception {
         assertAcked(prepareCreate("test").setMapping("title", "type=text," + randomStoreField() + "index_options=offsets"));
 

server/src/main/java/org/elasticsearch/search/fetch/subphase/highlight/AbstractHighlighterBuilder.java

@@ -561,14 +561,10 @@ public Integer phraseLimit() {
     }
 
     /**
-     * Set to a non-negative value which represents the max offset used to analyze
-     * the field thus avoiding exceptions if the field exceeds this limit.
+     * "maxAnalyzedOffset" might be non-negative int, null (unknown), or a negative int (defaulting to index analyzed offset).
      */
     @SuppressWarnings("unchecked")
     public HB maxAnalyzedOffset(Integer maxAnalyzedOffset) {
-        if (maxAnalyzedOffset != null && maxAnalyzedOffset <= 0) {
-            throw new IllegalArgumentException("[" + MAX_ANALYZED_OFFSET_FIELD + "] must be a positive integer");
-        }
         this.maxAnalyzedOffset = maxAnalyzedOffset;
         return (HB) this;
     }