Revert "[8.19] ESQL: Pushdown constructs doing case-insensitive regexes (elastic#128393) (elastic#128750) (elastic#128753) (elastic#128919)"

This reverts commit 34e08fb.

Author: dnhatn

benchmarks/src/main/java/org/elasticsearch/benchmark/compute/operator/EvalBenchmark.java

@@ -45,9 +45,9 @@
 import org.elasticsearch.xpack.esql.expression.function.scalar.math.RoundTo;
 import org.elasticsearch.xpack.esql.expression.function.scalar.multivalue.MvMin;
 import org.elasticsearch.xpack.esql.expression.function.scalar.nulls.Coalesce;
+import org.elasticsearch.xpack.esql.expression.function.scalar.string.RLike;
 import org.elasticsearch.xpack.esql.expression.function.scalar.string.ToLower;
 import org.elasticsearch.xpack.esql.expression.function.scalar.string.ToUpper;
-import org.elasticsearch.xpack.esql.expression.function.scalar.string.regex.RLike;
 import org.elasticsearch.xpack.esql.expression.predicate.operator.arithmetic.Add;
 import org.elasticsearch.xpack.esql.expression.predicate.operator.comparison.Equals;
 import org.elasticsearch.xpack.esql.expression.predicate.operator.comparison.LessThan;

docs/changelog/128393.yaml

@@ -234,7 +234,6 @@ static TransportVersion def(int id) {
     public static final TransportVersion DATA_STREAM_OPTIONS_API_REMOVE_INCLUDE_DEFAULTS_8_19 = def(8_841_0_41);
     public static final TransportVersion JOIN_ON_ALIASES_8_19 = def(8_841_0_42);
     public static final TransportVersion ILM_ADD_SKIP_SETTING_8_19 = def(8_841_0_43);
-    public static final TransportVersion ESQL_REGEX_MATCH_WITH_CASE_INSENSITIVITY_8_19 = def(8_841_0_44);
     /*
      * STOP! READ THIS FIRST! No, really,
      *        ____ _____ ___  ____  _        ____  _____    _    ____    _____ _   _ ___ ____    _____ ___ ____  ____ _____ _

docs/changelog/128750.yaml

@@ -16,11 +16,11 @@ public abstract class AbstractStringPattern implements StringPattern {
 
     private Automaton automaton;
 
-    public abstract Automaton createAutomaton(boolean ignoreCase);
+    public abstract Automaton createAutomaton();
 
     private Automaton automaton() {
         if (automaton == null) {
-            automaton = createAutomaton(false);
+            automaton = createAutomaton();
         }
         return automaton;
     }

server/src/main/java/org/elasticsearch/TransportVersions.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+package org.elasticsearch.xpack.esql.core.expression.predicate.regex;
+
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.xpack.esql.core.expression.Expression;
+import org.elasticsearch.xpack.esql.core.tree.Source;
+
+import java.io.IOException;
+
+public abstract class RLike extends RegexMatch<RLikePattern> {
+
+    public RLike(Source source, Expression value, RLikePattern pattern) {
+        super(source, value, pattern, false);
+    }
+
+    public RLike(Source source, Expression field, RLikePattern rLikePattern, boolean caseInsensitive) {
+        super(source, field, rLikePattern, caseInsensitive);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public String getWriteableName() {
+        throw new UnsupportedOperationException();
+    }
+
+}

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/predicate/regex/AbstractStringPattern.java

@@ -7,7 +7,6 @@
 package org.elasticsearch.xpack.esql.core.expression.predicate.regex;
 
 import org.apache.lucene.util.automaton.Automaton;
-import org.apache.lucene.util.automaton.Operations;
 import org.apache.lucene.util.automaton.RegExp;
 
 import java.util.Objects;
@@ -21,12 +20,8 @@ public RLikePattern(String regexpPattern) {
     }
 
     @Override
-    public Automaton createAutomaton(boolean ignoreCase) {
-        int matchFlags = ignoreCase ? RegExp.ASCII_CASE_INSENSITIVE : 0;
-        return Operations.determinize(
-            new RegExp(regexpPattern, RegExp.ALL, matchFlags).toAutomaton(),
-            Operations.DEFAULT_DETERMINIZE_WORK_LIMIT
-        );
+    public Automaton createAutomaton() {
+        return new RegExp(regexpPattern).toAutomaton();
     }
 
     @Override

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/predicate/regex/RLike.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+package org.elasticsearch.xpack.esql.core.expression.predicate.regex;
+
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.xpack.esql.core.expression.Expression;
+import org.elasticsearch.xpack.esql.core.tree.Source;
+
+import java.io.IOException;
+
+public abstract class WildcardLike extends RegexMatch<WildcardPattern> {
+
+    public WildcardLike(Source source, Expression left, WildcardPattern pattern) {
+        this(source, left, pattern, false);
+    }
+
+    public WildcardLike(Source source, Expression left, WildcardPattern pattern, boolean caseInsensitive) {
+        super(source, left, pattern, caseInsensitive);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public String getWriteableName() {
+        throw new UnsupportedOperationException();
+    }
+
+}

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/predicate/regex/RLikePattern.java

@@ -11,13 +11,10 @@
 import org.apache.lucene.util.automaton.Automaton;
 import org.apache.lucene.util.automaton.MinimizationOperations;
 import org.apache.lucene.util.automaton.Operations;
-import org.apache.lucene.util.automaton.RegExp;
 import org.elasticsearch.xpack.esql.core.util.StringUtils;
 
 import java.util.Objects;
 
-import static org.elasticsearch.xpack.esql.core.util.StringUtils.luceneWildcardToRegExp;
-
 /**
  * Similar to basic regex, supporting '?' wildcard for single character (same as regex  ".")
  * and '*' wildcard for multiple characters (same as regex ".*")
@@ -41,16 +38,9 @@ public String pattern() {
     }
 
     @Override
-    public Automaton createAutomaton(boolean ignoreCase) {
-        return ignoreCase
-            ? Operations.determinize(
-                new RegExp(luceneWildcardToRegExp(wildcard), RegExp.ALL, RegExp.ASCII_CASE_INSENSITIVE).toAutomaton(),
-                Operations.DEFAULT_DETERMINIZE_WORK_LIMIT
-            )
-            : MinimizationOperations.minimize(
-                WildcardQuery.toAutomaton(new Term(null, wildcard)),
-                Operations.DEFAULT_DETERMINIZE_WORK_LIMIT
-            );
+    public Automaton createAutomaton() {
+        Automaton automaton = WildcardQuery.toAutomaton(new Term(null, wildcard));
+        return MinimizationOperations.minimize(automaton, Operations.DEFAULT_DETERMINIZE_WORK_LIMIT);
     }
 
     @Override

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/predicate/regex/WildcardLike.java

@@ -7,7 +7,6 @@
 package org.elasticsearch.xpack.esql.core.util;
 
 import org.apache.lucene.document.InetAddressPoint;
-import org.apache.lucene.search.WildcardQuery;
 import org.apache.lucene.search.spell.LevenshteinDistance;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.CollectionUtil;
@@ -179,48 +178,6 @@ public static String wildcardToJavaPattern(String pattern, char escape) {
         return regex.toString();
     }
 
-    /**
-     * Translates a Lucene wildcard pattern to a Lucene RegExp one.
-     * Note: all RegExp "optional" characters are escaped too (allowing the use of the {@code RegExp.ALL} flag).
-     * @param wildcard Lucene wildcard pattern
-     * @return Lucene RegExp pattern
-     */
-    public static String luceneWildcardToRegExp(String wildcard) {
-        StringBuilder regex = new StringBuilder();
-
-        for (int i = 0, wcLen = wildcard.length(); i < wcLen; i++) {
-            char c = wildcard.charAt(i); // this will work chunking through Unicode as long as all values matched are ASCII
-            switch (c) {
-                case WildcardQuery.WILDCARD_STRING -> regex.append(".*");
-                case WildcardQuery.WILDCARD_CHAR -> regex.append(".");
-                case WildcardQuery.WILDCARD_ESCAPE -> {
-                    if (i + 1 < wcLen) {
-                        // consume the wildcard escaping, consider the next char
-                        char next = wildcard.charAt(i + 1);
-                        i++;
-                        switch (next) {
-                            case WildcardQuery.WILDCARD_STRING, WildcardQuery.WILDCARD_CHAR, WildcardQuery.WILDCARD_ESCAPE ->
-                                // escape `*`, `.`, `\`, since these are special chars in RegExp as well
-                                regex.append("\\");
-                            // default: unnecessary escaping -- just ignore the escaping
-                        }
-                        regex.append(next);
-                    } else {
-                        // "else fallthru, lenient parsing with a trailing \" -- according to WildcardQuery#toAutomaton
-                        regex.append("\\\\");
-                    }
-                }
-                // reserved RegExp characters
-                case '"', '$', '(', ')', '+', '.', '[', ']', '^', '{', '|', '}' -> regex.append("\\").append(c);
-                // reserved optional RegExp characters
-                case '#', '&', '<', '>' -> regex.append("\\").append(c);
-                default -> regex.append(c);
-            }
-        }
-
-        return regex.toString();
-    }
-
     /**
      * Translates a like pattern to a Lucene wildcard.
      * This methods pays attention to the custom escape char which gets converted into \ (used by Lucene).