From 212ea525a2b8442b72ce19f21611bab11c029059 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christoph=20B=C3=BCscher?= <cbuescher@posteo.de>
Date: Tue, 5 Mar 2019 14:30:10 +0100
Subject: [PATCH] Fix Fuzziness#asDistance(String) (#39643)

Currently Fuzziness#asDistance(String) doesn't work for custom AUTO values. If
the fuzziness is AUTO, the method returns the correct edit distance to use,
depending on the input string, but for custom AUTO values it currently always
returns an edit distance of 1. Correcting this and adding unit and integration
tests to catch these cases.

Closes #39614
---
 .../elasticsearch/common/unit/Fuzziness.java  |  2 +-
 .../common/unit/FuzzinessTests.java           | 24 +++++++++++++++++
 .../search/query/SearchQueryIT.java           | 26 +++++++++++++++++++
 3 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/server/src/main/java/org/elasticsearch/common/unit/Fuzziness.java b/server/src/main/java/org/elasticsearch/common/unit/Fuzziness.java
index aee0e9cd02ada..834277b5c7282 100644
--- a/server/src/main/java/org/elasticsearch/common/unit/Fuzziness.java
+++ b/server/src/main/java/org/elasticsearch/common/unit/Fuzziness.java
@@ -186,7 +186,7 @@ public int asDistance() {
     }
 
     public int asDistance(String text) {
-        if (this.equals(AUTO)) { //AUTO
+        if (this.equals(AUTO) || isAutoWithCustomValues()) { //AUTO
             final int len = termLen(text);
             if (len < lowDistance) {
                 return 0;
diff --git a/server/src/test/java/org/elasticsearch/common/unit/FuzzinessTests.java b/server/src/test/java/org/elasticsearch/common/unit/FuzzinessTests.java
index 5259cad23e8fb..a374f468a138b 100644
--- a/server/src/test/java/org/elasticsearch/common/unit/FuzzinessTests.java
+++ b/server/src/test/java/org/elasticsearch/common/unit/FuzzinessTests.java
@@ -169,4 +169,28 @@ private static Fuzziness doSerializeRoundtrip(Fuzziness in) throws IOException {
         StreamInput streamInput = output.bytes().streamInput();
         return new Fuzziness(streamInput);
     }
+
+    public void testAsDistanceString() {
+        Fuzziness fuzziness = Fuzziness.build("0");
+        assertEquals(0, fuzziness.asDistance(randomAlphaOfLengthBetween(0, 10)));
+        fuzziness = Fuzziness.build("1");
+        assertEquals(1, fuzziness.asDistance(randomAlphaOfLengthBetween(0, 10)));
+        fuzziness = Fuzziness.build("2");
+        assertEquals(2, fuzziness.asDistance(randomAlphaOfLengthBetween(0, 10)));
+
+        fuzziness = Fuzziness.build("AUTO");
+        assertEquals(0, fuzziness.asDistance(""));
+        assertEquals(0, fuzziness.asDistance("ab"));
+        assertEquals(1, fuzziness.asDistance("abc"));
+        assertEquals(1, fuzziness.asDistance("abcde"));
+        assertEquals(2, fuzziness.asDistance("abcdef"));
+
+        fuzziness = Fuzziness.build("AUTO:5,7");
+        assertEquals(0, fuzziness.asDistance(""));
+        assertEquals(0, fuzziness.asDistance("abcd"));
+        assertEquals(1, fuzziness.asDistance("abcde"));
+        assertEquals(1, fuzziness.asDistance("abcdef"));
+        assertEquals(2, fuzziness.asDistance("abcdefg"));
+
+    }
 }
diff --git a/server/src/test/java/org/elasticsearch/search/query/SearchQueryIT.java b/server/src/test/java/org/elasticsearch/search/query/SearchQueryIT.java
index ac0152582352d..7007c7650f41b 100644
--- a/server/src/test/java/org/elasticsearch/search/query/SearchQueryIT.java
+++ b/server/src/test/java/org/elasticsearch/search/query/SearchQueryIT.java
@@ -664,6 +664,32 @@ public void testMatchQueryNumeric() throws Exception {
         expectThrows(SearchPhaseExecutionException.class, () -> client().prepareSearch().setQuery(matchQuery("double", "2 3 4")).get());
     }
 
+    public void testMatchQueryFuzzy() throws Exception {
+        assertAcked(prepareCreate("test").addMapping("_doc", "text", "type=text"));
+
+        indexRandom(true, client().prepareIndex("test", "_doc", "1").setSource("text", "Unit"),
+                client().prepareIndex("test", "_doc", "2").setSource("text", "Unity"));
+
+        SearchResponse searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness("0")).get();
+        assertHitCount(searchResponse, 0L);
+
+        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness("1")).get();
+        assertHitCount(searchResponse, 2L);
+        assertSearchHits(searchResponse, "1", "2");
+
+        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness("AUTO")).get();
+        assertHitCount(searchResponse, 2L);
+        assertSearchHits(searchResponse, "1", "2");
+
+        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness("AUTO:5,7")).get();
+        assertHitCount(searchResponse, 0L);
+
+        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "unify").fuzziness("AUTO:5,7")).get();
+        assertHitCount(searchResponse, 1L);
+        assertSearchHits(searchResponse, "2");
+    }
+
+
     public void testMultiMatchQuery() throws Exception {
         createIndex("test");