Deprecate `levenstein` in favor of `levenshtein` (#27409)

Support both spellings thoughout 6.x, reporting the incorrect one as deprecated.

core/src/main/java/org/elasticsearch/search/suggest/phrase/DirectCandidateGeneratorBuilder.java

@@ -31,6 +31,8 @@ import org.elasticsearch.ExceptionsHelper;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.logging.DeprecationLogger;
+import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
@@ -45,6 +47,9 @@ import java.util.function.Consumer;
 
 public final class DirectCandidateGeneratorBuilder implements CandidateGenerator {
 
+    private static final DeprecationLogger DEPRECATION_LOGGER = new DeprecationLogger(
+            Loggers.getLogger(DirectCandidateGeneratorBuilder.class));
+
     private static final String TYPE = "direct_generator";
 
     public static final ParseField DIRECT_GENERATOR_FIELD = new ParseField(TYPE);
@@ -211,8 +216,8 @@ public final class DirectCandidateGeneratorBuilder implements CandidateGenerator
      * string distance for terms inside the index.
      * <li><code>damerau_levenshtein</code> - String distance algorithm
      * based on Damerau-Levenshtein algorithm.
-     * <li><code>levenstein</code> - String distance algorithm based on
-     * Levenstein edit distance algorithm.
+     * <li><code>levenshtein</code> - String distance algorithm based on
+     * Levenshtein edit distance algorithm.
      * <li><code>jarowinkler</code> - String distance algorithm based on
      * Jaro-Winkler algorithm.
      * <li><code>ngram</code> - String distance algorithm based on character
@@ -458,13 +463,16 @@ public final class DirectCandidateGeneratorBuilder implements CandidateGenerator
         }
     }
 
-    private static StringDistance resolveDistance(String distanceVal) {
+    static StringDistance resolveDistance(String distanceVal) {
         distanceVal = distanceVal.toLowerCase(Locale.US);
         if ("internal".equals(distanceVal)) {
             return DirectSpellChecker.INTERNAL_LEVENSHTEIN;
         } else if ("damerau_levenshtein".equals(distanceVal) || "damerauLevenshtein".equals(distanceVal)) {
             return new LuceneLevenshteinDistance();
         } else if ("levenstein".equals(distanceVal)) {
+            DEPRECATION_LOGGER.deprecated("Deprecated distance [levenstein] used, replaced by [levenshtein]");
+            return new LevensteinDistance();
+        } else if ("levenshtein".equals(distanceVal)) {
             return new LevensteinDistance();
             // TODO Jaro and Winkler are 2 people - so apply same naming logic
             // as damerau_levenshtein

core/src/main/java/org/elasticsearch/search/suggest/term/TermSuggestionBuilder.java

@@ -30,6 +30,8 @@ import org.elasticsearch.common.ParsingException;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.common.logging.DeprecationLogger;
+import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.index.query.QueryShardContext;
@@ -66,6 +68,9 @@ import static org.elasticsearch.search.suggest.phrase.DirectCandidateGeneratorBu
  * global options, but are only applicable for this suggestion.
  */
 public class TermSuggestionBuilder extends SuggestionBuilder<TermSuggestionBuilder> {
+
+    private static final DeprecationLogger DEPRECATION_LOGGER = new DeprecationLogger(Loggers.getLogger(TermSuggestionBuilder.class));
+
     private static final String SUGGESTION_NAME = "term";
 
     private SuggestMode suggestMode = SuggestMode.MISSING;
@@ -214,8 +219,8 @@ public class TermSuggestionBuilder extends SuggestionBuilder<TermSuggestionBuild
      * string distance for terms inside the index.
      * <li><code>damerau_levenshtein</code> - String distance algorithm based on
      * Damerau-Levenshtein algorithm.
-     * <li><code>levenstein</code> - String distance algorithm based on
-     * Levenstein edit distance algorithm.
+     * <li><code>levenshtein</code> - String distance algorithm based on
+     * Levenshtein edit distance algorithm.
      * <li><code>jarowinkler</code> - String distance algorithm based on
      * Jaro-Winkler algorithm.
      * <li><code>ngram</code> - String distance algorithm based on character
@@ -543,8 +548,8 @@ public class TermSuggestionBuilder extends SuggestionBuilder<TermSuggestionBuild
                 return new LuceneLevenshteinDistance();
             }
         },
-        /** String distance algorithm based on Levenstein edit distance algorithm. */
-        LEVENSTEIN {
+        /** String distance algorithm based on Levenshtein edit distance algorithm. */
+        LEVENSHTEIN {
             @Override
             public StringDistance toLucene() {
                 return new LevensteinDistance();
@@ -584,7 +589,10 @@ public class TermSuggestionBuilder extends SuggestionBuilder<TermSuggestionBuild
                 case "damerauLevenshtein":
                     return DAMERAU_LEVENSHTEIN;
                 case "levenstein":
-                    return LEVENSTEIN;
+                    DEPRECATION_LOGGER.deprecated("Deprecated distance [levenstein] used, replaced by [levenshtein]");
+                    return LEVENSHTEIN;
+                case "levenshtein":
+                    return LEVENSHTEIN;
                 case "ngram":
                     return NGRAM;
                 case "jarowinkler":

core/src/test/java/org/elasticsearch/search/suggest/phrase/DirectCandidateGeneratorTests.java

@@ -19,6 +19,11 @@
 
 package org.elasticsearch.search.suggest.phrase;
 
+import org.apache.lucene.search.spell.DirectSpellChecker;
+import org.apache.lucene.search.spell.JaroWinklerDistance;
+import org.apache.lucene.search.spell.LevensteinDistance;
+import org.apache.lucene.search.spell.LuceneLevenshteinDistance;
+import org.apache.lucene.search.spell.NGramDistance;
 import org.elasticsearch.common.ParsingException;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
 import org.elasticsearch.common.xcontent.ToXContent;
@@ -38,6 +43,8 @@ import java.util.List;
 import java.util.function.Supplier;
 
 import static org.elasticsearch.test.EqualsHashCodeTestUtils.checkEqualsAndHashCode;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.core.IsInstanceOf.instanceOf;
 
 public class DirectCandidateGeneratorTests extends ESTestCase {
     private static final int NUMBER_OF_RUNS = 20;
@@ -65,6 +72,22 @@ public class DirectCandidateGeneratorTests extends ESTestCase {
         }
     }
 
+    public void testFromString() {
+        assertThat(DirectCandidateGeneratorBuilder.resolveDistance("internal"), equalTo(DirectSpellChecker.INTERNAL_LEVENSHTEIN));
+        assertThat(DirectCandidateGeneratorBuilder.resolveDistance("damerau_levenshtein"), instanceOf(LuceneLevenshteinDistance.class));
+        assertThat(DirectCandidateGeneratorBuilder.resolveDistance("levenshtein"), instanceOf(LevensteinDistance.class));
+        assertThat(DirectCandidateGeneratorBuilder.resolveDistance("jaroWinkler"), instanceOf(JaroWinklerDistance.class));
+        assertThat(DirectCandidateGeneratorBuilder.resolveDistance("ngram"), instanceOf(NGramDistance.class));
+
+        expectThrows(IllegalArgumentException.class, () -> DirectCandidateGeneratorBuilder.resolveDistance("doesnt_exist"));
+        expectThrows(NullPointerException.class, () -> DirectCandidateGeneratorBuilder.resolveDistance(null));
+    }
+
+    public void testLevensteinDeprecation() {
+        assertThat(DirectCandidateGeneratorBuilder.resolveDistance("levenstein"), instanceOf(LevensteinDistance.class));
+        assertWarnings("Deprecated distance [levenstein] used, replaced by [levenshtein]");
+    }
+
     private static DirectCandidateGeneratorBuilder mutate(DirectCandidateGeneratorBuilder original) throws IOException {
         DirectCandidateGeneratorBuilder mutation = copy(original);
         List<Supplier<DirectCandidateGeneratorBuilder>> mutators = new ArrayList<>();
@@ -89,7 +112,7 @@ public class DirectCandidateGeneratorTests extends ESTestCase {
         mutators.add(() -> mutation.preFilter(original.preFilter() == null ? "preFilter" : original.preFilter() + "_other"));
         mutators.add(() -> mutation.sort(original.sort() == null ? "score" : original.sort() + "_other"));
         mutators.add(
-                () -> mutation.stringDistance(original.stringDistance() == null ? "levenstein" : original.stringDistance() + "_other"));
+                () -> mutation.stringDistance(original.stringDistance() == null ? "levenshtein" : original.stringDistance() + "_other"));
         mutators.add(() -> mutation.suggestMode(original.suggestMode() == null ? "missing" : original.suggestMode() + "_other"));
         return randomFrom(mutators).get();
     }
@@ -189,7 +212,7 @@ public class DirectCandidateGeneratorTests extends ESTestCase {
         maybeSet(generator::postFilter, randomAlphaOfLengthBetween(1, 20));
         maybeSet(generator::size, randomIntBetween(1, 20));
         maybeSet(generator::sort, randomFrom("score", "frequency"));
-        maybeSet(generator::stringDistance, randomFrom("internal", "damerau_levenshtein", "levenstein", "jarowinkler", "ngram"));
+        maybeSet(generator::stringDistance, randomFrom("internal", "damerau_levenshtein", "levenshtein", "jarowinkler", "ngram"));
         maybeSet(generator::suggestMode, randomFrom("missing", "popular", "always"));
         return generator;
     }

core/src/test/java/org/elasticsearch/search/suggest/term/StringDistanceImplTests.java

@@ -20,10 +20,10 @@
 package org.elasticsearch.search.suggest.term;
 
 import org.elasticsearch.common.io.stream.AbstractWriteableEnumTestCase;
+import org.elasticsearch.search.suggest.term.TermSuggestionBuilder.StringDistanceImpl;
 
 import java.io.IOException;
 
-import static org.elasticsearch.search.suggest.term.TermSuggestionBuilder.StringDistanceImpl;
 import static org.hamcrest.Matchers.equalTo;
 
 /**
@@ -38,7 +38,7 @@ public class StringDistanceImplTests extends AbstractWriteableEnumTestCase {
     public void testValidOrdinals() {
         assertThat(StringDistanceImpl.INTERNAL.ordinal(), equalTo(0));
         assertThat(StringDistanceImpl.DAMERAU_LEVENSHTEIN.ordinal(), equalTo(1));
-        assertThat(StringDistanceImpl.LEVENSTEIN.ordinal(), equalTo(2));
+        assertThat(StringDistanceImpl.LEVENSHTEIN.ordinal(), equalTo(2));
         assertThat(StringDistanceImpl.JAROWINKLER.ordinal(), equalTo(3));
         assertThat(StringDistanceImpl.NGRAM.ordinal(), equalTo(4));
     }
@@ -47,28 +47,27 @@ public class StringDistanceImplTests extends AbstractWriteableEnumTestCase {
     public void testFromString() {
         assertThat(StringDistanceImpl.resolve("internal"), equalTo(StringDistanceImpl.INTERNAL));
         assertThat(StringDistanceImpl.resolve("damerau_levenshtein"), equalTo(StringDistanceImpl.DAMERAU_LEVENSHTEIN));
-        assertThat(StringDistanceImpl.resolve("levenstein"), equalTo(StringDistanceImpl.LEVENSTEIN));
+        assertThat(StringDistanceImpl.resolve("levenshtein"), equalTo(StringDistanceImpl.LEVENSHTEIN));
         assertThat(StringDistanceImpl.resolve("jarowinkler"), equalTo(StringDistanceImpl.JAROWINKLER));
         assertThat(StringDistanceImpl.resolve("ngram"), equalTo(StringDistanceImpl.NGRAM));
+
         final String doesntExist = "doesnt_exist";
-        try {
-            StringDistanceImpl.resolve(doesntExist);
-            fail("StringDistanceImpl should not have an element " + doesntExist);
-        } catch (IllegalArgumentException e) {
-        }
-        try {
-            StringDistanceImpl.resolve(null);
-            fail("StringDistanceImpl.resolve on a null value should throw an exception.");
-        } catch (NullPointerException e) {
-            assertThat(e.getMessage(), equalTo("Input string is null"));
-        }
+        expectThrows(IllegalArgumentException.class, () -> StringDistanceImpl.resolve(doesntExist)); 
+        
+        NullPointerException e = expectThrows(NullPointerException.class, () -> StringDistanceImpl.resolve(null));
+        assertThat(e.getMessage(), equalTo("Input string is null"));
+    }
+
+    public void testLevensteinDeprecation() {
+        assertThat(StringDistanceImpl.resolve("levenstein"), equalTo(StringDistanceImpl.LEVENSHTEIN));
+        assertWarnings("Deprecated distance [levenstein] used, replaced by [levenshtein]");
     }
 
     @Override
     public void testWriteTo() throws IOException {
         assertWriteToStream(StringDistanceImpl.INTERNAL, 0);
         assertWriteToStream(StringDistanceImpl.DAMERAU_LEVENSHTEIN, 1);
-        assertWriteToStream(StringDistanceImpl.LEVENSTEIN, 2);
+        assertWriteToStream(StringDistanceImpl.LEVENSHTEIN, 2);
         assertWriteToStream(StringDistanceImpl.JAROWINKLER, 3);
         assertWriteToStream(StringDistanceImpl.NGRAM, 4);
     }
@@ -77,7 +76,7 @@ public class StringDistanceImplTests extends AbstractWriteableEnumTestCase {
     public void testReadFrom() throws IOException {
         assertReadFromStream(0, StringDistanceImpl.INTERNAL);
         assertReadFromStream(1, StringDistanceImpl.DAMERAU_LEVENSHTEIN);
-        assertReadFromStream(2, StringDistanceImpl.LEVENSTEIN);
+        assertReadFromStream(2, StringDistanceImpl.LEVENSHTEIN);
         assertReadFromStream(3, StringDistanceImpl.JAROWINKLER);
         assertReadFromStream(4, StringDistanceImpl.NGRAM);
     }

core/src/test/java/org/elasticsearch/search/suggest/term/TermSuggestionBuilderTests.java

@@ -99,7 +99,7 @@ public class TermSuggestionBuilderTests extends AbstractSuggestionBuilderTestCas
         switch (randomVal) {
             case 0: return StringDistanceImpl.INTERNAL;
             case 1: return StringDistanceImpl.DAMERAU_LEVENSHTEIN;
-            case 2: return StringDistanceImpl.LEVENSTEIN;
+            case 2: return StringDistanceImpl.LEVENSHTEIN;
             case 3: return StringDistanceImpl.JAROWINKLER;
             case 4: return StringDistanceImpl.NGRAM;
             default: throw new IllegalArgumentException("No string distance algorithm with an ordinal of " + randomVal);

docs/reference/search/suggesters/term-suggest.asciidoc

@@ -116,7 +116,7 @@ doesn't take the query into account that is part of request.
     for comparing string distance for terms inside the index.
     `damerau_levenshtein` - String distance algorithm based on
     Damerau-Levenshtein algorithm.
-    `levenstein` - String distance algorithm based on Levenstein edit distance
+    `levenshtein` - String distance algorithm based on Levenshtein edit distance
     algorithm.
     `jarowinkler` - String distance algorithm based on Jaro-Winkler algorithm.
     `ngram` - String distance algorithm based on character n-grams.