Throw Error on deprecated nGram and edgeNGram custom filters (#50376)

The camel-case `nGram` and `edgeNGram` filter names were deprecated in 6. We
currently throw errors on new indices when they are used. However these errors
are currently only thrown for pre-configured filters, adding them as custom
filters doesn't trigger the warning and error. This change adds the appropriate
exceptions for `nGram` and `edgeNGram` respectively.

Closes #50360

modules/analysis-common/src/main/java/org/elasticsearch/analysis/common/CommonAnalysisPlugin.java

@@ -118,9 +118,11 @@
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
 import org.elasticsearch.common.logging.DeprecationLogger;
 import org.elasticsearch.common.regex.Regex;
+import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.env.NodeEnvironment;
+import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.analysis.AnalyzerProvider;
 import org.elasticsearch.index.analysis.CharFilterFactory;
 import org.elasticsearch.index.analysis.PreBuiltAnalyzerProviderFactory;
@@ -238,7 +240,24 @@ public Map<String, AnalysisProvider<TokenFilterFactory>> getTokenFilters() {
         filters.put("dictionary_decompounder", requiresAnalysisSettings(DictionaryCompoundWordTokenFilterFactory::new));
         filters.put("dutch_stem", DutchStemTokenFilterFactory::new);
         filters.put("edge_ngram", EdgeNGramTokenFilterFactory::new);
-        filters.put("edgeNGram", EdgeNGramTokenFilterFactory::new);
+        filters.put("edgeNGram", (IndexSettings indexSettings, Environment environment, String name, Settings settings) -> {
+            return new EdgeNGramTokenFilterFactory(indexSettings, environment, name, settings) {
+                @Override
+                public TokenStream create(TokenStream tokenStream) {
+                    if (indexSettings.getIndexVersionCreated().onOrAfter(org.elasticsearch.Version.V_8_0_0)) {
+                        throw new IllegalArgumentException(
+                                "The [edgeNGram] token filter name was deprecated in 6.4 and cannot be used in new indices. "
+                                        + "Please change the filter name to [edge_ngram] instead.");
+                    } else {
+                        deprecationLogger.deprecatedAndMaybeLog("edgeNGram_deprecation",
+                                "The [edgeNGram] token filter name is deprecated and will be removed in a future version. "
+                                        + "Please change the filter name to [edge_ngram] instead.");
+                    }
+                    return super.create(tokenStream);
+                }
+
+            };
+        });
         filters.put("elision", requiresAnalysisSettings(ElisionTokenFilterFactory::new));
         filters.put("fingerprint", FingerprintTokenFilterFactory::new);
         filters.put("flatten_graph", FlattenGraphTokenFilterFactory::new);
@@ -258,7 +277,24 @@ public Map<String, AnalysisProvider<TokenFilterFactory>> getTokenFilters() {
         filters.put("min_hash", MinHashTokenFilterFactory::new);
         filters.put("multiplexer", MultiplexerTokenFilterFactory::new);
         filters.put("ngram", NGramTokenFilterFactory::new);
-        filters.put("nGram", NGramTokenFilterFactory::new);
+        filters.put("nGram", (IndexSettings indexSettings, Environment environment, String name, Settings settings) -> {
+            return new NGramTokenFilterFactory(indexSettings, environment, name, settings) {
+                @Override
+                public TokenStream create(TokenStream tokenStream) {
+                    if (indexSettings.getIndexVersionCreated().onOrAfter(org.elasticsearch.Version.V_8_0_0)) {
+                        throw new IllegalArgumentException(
+                                "The [nGram] token filter name was deprecated in 6.4 and cannot be used in new indices. "
+                                        + "Please change the filter name to [ngram] instead.");
+                    } else {
+                        deprecationLogger.deprecatedAndMaybeLog("nGram_deprecation",
+                                "The [nGram] token filter name is deprecated and will be removed in a future version. "
+                                        + "Please change the filter name to [ngram] instead.");
+                    }
+                    return super.create(tokenStream);
+                }
+
+            };
+        });
         filters.put("pattern_capture", requiresAnalysisSettings(PatternCaptureGroupTokenFilterFactory::new));
         filters.put("pattern_replace", requiresAnalysisSettings(PatternReplaceTokenFilterFactory::new));
         filters.put("persian_normalization", PersianNormalizationFilterFactory::new);

modules/analysis-common/src/test/java/org/elasticsearch/analysis/common/CommonAnalysisPluginTests.java

@@ -0,0 +1,129 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.analysis.common;
+
+import org.apache.lucene.analysis.MockTokenizer;
+import org.apache.lucene.analysis.Tokenizer;
+import org.elasticsearch.Version;
+import org.elasticsearch.cluster.metadata.IndexMetaData;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.env.Environment;
+import org.elasticsearch.index.analysis.TokenFilterFactory;
+import org.elasticsearch.test.ESTestCase;
+import org.elasticsearch.test.IndexSettingsModule;
+import org.elasticsearch.test.VersionUtils;
+
+import java.io.IOException;
+import java.io.StringReader;
+import java.util.Map;
+
+public class CommonAnalysisPluginTests extends ESTestCase {
+
+    /**
+     * Check that the deprecated "nGram" filter throws exception for indices created since 7.0.0 and
+     * logs a warning for earlier indices when the filter is used as a custom filter
+     */
+    public void testNGramFilterInCustomAnalyzerDeprecationError() throws IOException {
+        final Settings settings = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir())
+            .put(IndexMetaData.SETTING_VERSION_CREATED,
+                VersionUtils.randomVersionBetween(random(), Version.V_8_0_0, Version.CURRENT))
+            .put("index.analysis.analyzer.custom_analyzer.type", "custom")
+            .put("index.analysis.analyzer.custom_analyzer.tokenizer", "standard")
+            .putList("index.analysis.analyzer.custom_analyzer.filter", "my_ngram")
+            .put("index.analysis.filter.my_ngram.type", "nGram")
+            .build();
+
+        try (CommonAnalysisPlugin commonAnalysisPlugin = new CommonAnalysisPlugin()) {
+            Map<String, TokenFilterFactory> tokenFilters = createTestAnalysis(IndexSettingsModule.newIndexSettings("index", settings),
+                    settings, commonAnalysisPlugin).tokenFilter;
+            TokenFilterFactory tokenFilterFactory = tokenFilters.get("nGram");
+            Tokenizer tokenizer = new MockTokenizer();
+            tokenizer.setReader(new StringReader("foo bar"));
+
+            IllegalArgumentException ex = expectThrows(IllegalArgumentException.class, () -> tokenFilterFactory.create(tokenizer));
+            assertEquals("The [nGram] token filter name was deprecated in 6.4 and cannot be used in new indices. "
+                    + "Please change the filter name to [ngram] instead.", ex.getMessage());
+        }
+
+        final Settings settingsPre7 = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir())
+                .put(IndexMetaData.SETTING_VERSION_CREATED, VersionUtils.randomVersionBetween(random(), Version.V_7_0_0, Version.V_7_6_0))
+                .put("index.analysis.analyzer.custom_analyzer.type", "custom")
+                .put("index.analysis.analyzer.custom_analyzer.tokenizer", "standard")
+                .putList("index.analysis.analyzer.custom_analyzer.filter", "my_ngram").put("index.analysis.filter.my_ngram.type", "nGram")
+                .build();
+        try (CommonAnalysisPlugin commonAnalysisPlugin = new CommonAnalysisPlugin()) {
+            Map<String, TokenFilterFactory> tokenFilters = createTestAnalysis(IndexSettingsModule.newIndexSettings("index", settingsPre7),
+                    settingsPre7, commonAnalysisPlugin).tokenFilter;
+            TokenFilterFactory tokenFilterFactory = tokenFilters.get("nGram");
+            Tokenizer tokenizer = new MockTokenizer();
+            tokenizer.setReader(new StringReader("foo bar"));
+            assertNotNull(tokenFilterFactory.create(tokenizer));
+            assertWarnings("The [nGram] token filter name is deprecated and will be removed in a future version. "
+                    + "Please change the filter name to [ngram] instead.");
+        }
+    }
+
+    /**
+     * Check that the deprecated "edgeNGram" filter throws exception for indices created since 7.0.0 and
+     * logs a warning for earlier indices when the filter is used as a custom filter
+     */
+    public void testEdgeNGramFilterInCustomAnalyzerDeprecationError() throws IOException {
+        final Settings settings = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir())
+            .put(IndexMetaData.SETTING_VERSION_CREATED,
+                VersionUtils.randomVersionBetween(random(), Version.V_8_0_0, Version.CURRENT))
+            .put("index.analysis.analyzer.custom_analyzer.type", "custom")
+            .put("index.analysis.analyzer.custom_analyzer.tokenizer", "standard")
+            .putList("index.analysis.analyzer.custom_analyzer.filter", "my_ngram")
+            .put("index.analysis.filter.my_ngram.type", "edgeNGram")
+            .build();
+
+        try (CommonAnalysisPlugin commonAnalysisPlugin = new CommonAnalysisPlugin()) {
+            Map<String, TokenFilterFactory> tokenFilters = createTestAnalysis(IndexSettingsModule.newIndexSettings("index", settings),
+                    settings, commonAnalysisPlugin).tokenFilter;
+            TokenFilterFactory tokenFilterFactory = tokenFilters.get("edgeNGram");
+            Tokenizer tokenizer = new MockTokenizer();
+            tokenizer.setReader(new StringReader("foo bar"));
+
+            IllegalArgumentException ex = expectThrows(IllegalArgumentException.class, () -> tokenFilterFactory.create(tokenizer));
+            assertEquals("The [edgeNGram] token filter name was deprecated in 6.4 and cannot be used in new indices. "
+                    + "Please change the filter name to [edge_ngram] instead.", ex.getMessage());
+        }
+
+        final Settings settingsPre7 = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir())
+                .put(IndexMetaData.SETTING_VERSION_CREATED,
+                    VersionUtils.randomVersionBetween(random(), Version.V_7_0_0, Version.V_7_6_0))
+                .put("index.analysis.analyzer.custom_analyzer.type", "custom")
+                .put("index.analysis.analyzer.custom_analyzer.tokenizer", "standard")
+                .putList("index.analysis.analyzer.custom_analyzer.filter", "my_ngram")
+                .put("index.analysis.filter.my_ngram.type", "edgeNGram")
+                .build();
+
+        try (CommonAnalysisPlugin commonAnalysisPlugin = new CommonAnalysisPlugin()) {
+            Map<String, TokenFilterFactory> tokenFilters = createTestAnalysis(IndexSettingsModule.newIndexSettings("index", settingsPre7),
+                    settingsPre7, commonAnalysisPlugin).tokenFilter;
+            TokenFilterFactory tokenFilterFactory = tokenFilters.get("edgeNGram");
+            Tokenizer tokenizer = new MockTokenizer();
+            tokenizer.setReader(new StringReader("foo bar"));
+            assertNotNull(tokenFilterFactory.create(tokenizer));
+            assertWarnings("The [edgeNGram] token filter name is deprecated and will be removed in a future version. "
+                    + "Please change the filter name to [edge_ngram] instead.");
+        }
+    }
+}