Revert 7.x related code from analysis common (#118972)

This reverts #113009 and re-introduces v7 compatibility logic and previous v7 tests
since we now support v7 indices as read-only on v9.

Author: cbuescher

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

@@ -101,7 +101,12 @@
 import org.apache.lucene.analysis.tr.TurkishAnalyzer;
 import org.apache.lucene.analysis.util.ElisionFilter;
 import org.apache.lucene.util.SetOnce;
+import org.elasticsearch.common.logging.DeprecationCategory;
+import org.elasticsearch.common.logging.DeprecationLogger;
 import org.elasticsearch.common.regex.Regex;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.env.Environment;
+import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.IndexVersions;
 import org.elasticsearch.index.analysis.AnalyzerProvider;
 import org.elasticsearch.index.analysis.CharFilterFactory;
@@ -134,6 +139,8 @@
 
 public class CommonAnalysisPlugin extends Plugin implements AnalysisPlugin, ScriptPlugin {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(CommonAnalysisPlugin.class);
+
     private final SetOnce<ScriptService> scriptServiceHolder = new SetOnce<>();
     private final SetOnce<SynonymsManagementAPIService> synonymsManagementServiceHolder = new SetOnce<>();
 
@@ -224,6 +231,28 @@ 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", (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(IndexVersions.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.warn(
+                            DeprecationCategory.ANALYSIS,
+                            "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);
@@ -243,6 +272,28 @@ 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", (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(IndexVersions.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.warn(
+                            DeprecationCategory.ANALYSIS,
+                            "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);
@@ -294,7 +345,39 @@ public Map<String, AnalysisProvider<TokenizerFactory>> getTokenizers() {
         tokenizers.put("simple_pattern", SimplePatternTokenizerFactory::new);
         tokenizers.put("simple_pattern_split", SimplePatternSplitTokenizerFactory::new);
         tokenizers.put("thai", ThaiTokenizerFactory::new);
+        tokenizers.put("nGram", (IndexSettings indexSettings, Environment environment, String name, Settings settings) -> {
+            if (indexSettings.getIndexVersionCreated().onOrAfter(IndexVersions.V_8_0_0)) {
+                throw new IllegalArgumentException(
+                    "The [nGram] tokenizer name was deprecated in 7.6. "
+                        + "Please use the tokenizer name to [ngram] for indices created in versions 8 or higher instead."
+                );
+            } else if (indexSettings.getIndexVersionCreated().onOrAfter(IndexVersions.V_7_6_0)) {
+                deprecationLogger.warn(
+                    DeprecationCategory.ANALYSIS,
+                    "nGram_tokenizer_deprecation",
+                    "The [nGram] tokenizer name is deprecated and will be removed in a future version. "
+                        + "Please change the tokenizer name to [ngram] instead."
+                );
+            }
+            return new NGramTokenizerFactory(indexSettings, environment, name, settings);
+        });
         tokenizers.put("ngram", NGramTokenizerFactory::new);
+        tokenizers.put("edgeNGram", (IndexSettings indexSettings, Environment environment, String name, Settings settings) -> {
+            if (indexSettings.getIndexVersionCreated().onOrAfter(IndexVersions.V_8_0_0)) {
+                throw new IllegalArgumentException(
+                    "The [edgeNGram] tokenizer name was deprecated in 7.6. "
+                        + "Please use the tokenizer name to [edge_nGram] for indices created in versions 8 or higher instead."
+                );
+            } else if (indexSettings.getIndexVersionCreated().onOrAfter(IndexVersions.V_7_6_0)) {
+                deprecationLogger.warn(
+                    DeprecationCategory.ANALYSIS,
+                    "edgeNGram_tokenizer_deprecation",
+                    "The [edgeNGram] tokenizer name is deprecated and will be removed in a future version. "
+                        + "Please change the tokenizer name to [edge_ngram] instead."
+                );
+            }
+            return new EdgeNGramTokenizerFactory(indexSettings, environment, name, settings);
+        });
         tokenizers.put("edge_ngram", EdgeNGramTokenizerFactory::new);
         tokenizers.put("char_group", CharGroupTokenizerFactory::new);
         tokenizers.put("classic", ClassicTokenizerFactory::new);
@@ -505,17 +588,53 @@ public List<PreConfiguredTokenizer> getPreConfiguredTokenizers() {
         tokenizers.add(PreConfiguredTokenizer.singleton("letter", LetterTokenizer::new));
         tokenizers.add(PreConfiguredTokenizer.singleton("whitespace", WhitespaceTokenizer::new));
         tokenizers.add(PreConfiguredTokenizer.singleton("ngram", NGramTokenizer::new));
-        tokenizers.add(
-            PreConfiguredTokenizer.indexVersion(
-                "edge_ngram",
-                (version) -> new EdgeNGramTokenizer(NGramTokenizer.DEFAULT_MIN_NGRAM_SIZE, NGramTokenizer.DEFAULT_MAX_NGRAM_SIZE)
-            )
-        );
+        tokenizers.add(PreConfiguredTokenizer.indexVersion("edge_ngram", (version) -> {
+            if (version.onOrAfter(IndexVersions.V_7_3_0)) {
+                return new EdgeNGramTokenizer(NGramTokenizer.DEFAULT_MIN_NGRAM_SIZE, NGramTokenizer.DEFAULT_MAX_NGRAM_SIZE);
+            }
+            return new EdgeNGramTokenizer(EdgeNGramTokenizer.DEFAULT_MIN_GRAM_SIZE, EdgeNGramTokenizer.DEFAULT_MAX_GRAM_SIZE);
+        }));
         tokenizers.add(PreConfiguredTokenizer.singleton("pattern", () -> new PatternTokenizer(Regex.compile("\\W+", null), -1)));
         tokenizers.add(PreConfiguredTokenizer.singleton("thai", ThaiTokenizer::new));
         // TODO deprecate and remove in API
         // This is already broken with normalization, so backwards compat isn't necessary?
         tokenizers.add(PreConfiguredTokenizer.singleton("lowercase", XLowerCaseTokenizer::new));
+
+        tokenizers.add(PreConfiguredTokenizer.indexVersion("nGram", (version) -> {
+            if (version.onOrAfter(IndexVersions.V_8_0_0)) {
+                throw new IllegalArgumentException(
+                    "The [nGram] tokenizer name was deprecated in 7.6. "
+                        + "Please use the tokenizer name to [ngram] for indices created in versions 8 or higher instead."
+                );
+            } else if (version.onOrAfter(IndexVersions.V_7_6_0)) {
+                deprecationLogger.warn(
+                    DeprecationCategory.ANALYSIS,
+                    "nGram_tokenizer_deprecation",
+                    "The [nGram] tokenizer name is deprecated and will be removed in a future version. "
+                        + "Please change the tokenizer name to [ngram] instead."
+                );
+            }
+            return new NGramTokenizer();
+        }));
+        tokenizers.add(PreConfiguredTokenizer.indexVersion("edgeNGram", (version) -> {
+            if (version.onOrAfter(IndexVersions.V_8_0_0)) {
+                throw new IllegalArgumentException(
+                    "The [edgeNGram] tokenizer name was deprecated in 7.6. "
+                        + "Please use the tokenizer name to [edge_ngram] for indices created in versions 8 or higher instead."
+                );
+            } else if (version.onOrAfter(IndexVersions.V_7_6_0)) {
+                deprecationLogger.warn(
+                    DeprecationCategory.ANALYSIS,
+                    "edgeNGram_tokenizer_deprecation",
+                    "The [edgeNGram] tokenizer name is deprecated and will be removed in a future version. "
+                        + "Please change the tokenizer name to [edge_ngram] instead."
+                );
+            }
+            if (version.onOrAfter(IndexVersions.V_7_3_0)) {
+                return new EdgeNGramTokenizer(NGramTokenizer.DEFAULT_MIN_NGRAM_SIZE, NGramTokenizer.DEFAULT_MAX_NGRAM_SIZE);
+            }
+            return new EdgeNGramTokenizer(EdgeNGramTokenizer.DEFAULT_MIN_GRAM_SIZE, EdgeNGramTokenizer.DEFAULT_MAX_GRAM_SIZE);
+        }));
         tokenizers.add(PreConfiguredTokenizer.singleton("PathHierarchy", PathHierarchyTokenizer::new));
 
         return tokenizers;