From 5bbcb72f2f120930c5b831036f4ab77719ad50a9 Mon Sep 17 00:00:00 2001
From: Tanner Clary <tannerclary@google.com>
Date: Thu, 15 Feb 2024 17:14:55 -0800
Subject: [PATCH] Revert "[CALCITE-6006] RelToSqlConverter loses charset
 information"

This reverts commit 485a5d0ae3274a83a36788290b3bdc4d973387b4.
---
 .../calcite/rel/rel2sql/SqlImplementor.java      | 16 +---------------
 .../rel/rel2sql/RelToSqlConverterTest.java       | 12 ------------
 2 files changed, 1 insertion(+), 27 deletions(-)

diff --git a/core/src/main/java/org/apache/calcite/rel/rel2sql/SqlImplementor.java b/core/src/main/java/org/apache/calcite/rel/rel2sql/SqlImplementor.java
index ffdbbafba6d..ad8b160835f 100644
--- a/core/src/main/java/org/apache/calcite/rel/rel2sql/SqlImplementor.java
+++ b/core/src/main/java/org/apache/calcite/rel/rel2sql/SqlImplementor.java
@@ -16,7 +16,6 @@
  */
 package org.apache.calcite.rel.rel2sql;
 
-import org.apache.calcite.config.CalciteSystemProperty;
 import org.apache.calcite.linq4j.Ord;
 import org.apache.calcite.linq4j.tree.Expressions;
 import org.apache.calcite.plan.RelOptUtil;
@@ -94,7 +93,6 @@
 import org.apache.calcite.sql.validate.SqlValidatorUtil;
 import org.apache.calcite.util.DateString;
 import org.apache.calcite.util.ImmutableBitSet;
-import org.apache.calcite.util.NlsString;
 import org.apache.calcite.util.Pair;
 import org.apache.calcite.util.RangeSets;
 import org.apache.calcite.util.Sarg;
@@ -1425,20 +1423,8 @@ public static SqlNode toSql(RexLiteral literal) {
             () -> "literal " + literal
                 + " has null SqlTypeFamily, and is SqlTypeName is " + typeName);
     switch (family) {
-    case CHARACTER: {
-      final NlsString value = literal.getValueAs(NlsString.class);
-      if (value != null) {
-        final String defaultCharset = CalciteSystemProperty.DEFAULT_CHARSET.value();
-        final String charsetName = value.getCharsetName();
-        if (!defaultCharset.equals(charsetName)) {
-          // Set the charset only if it is not the same as the default charset
-          return SqlLiteral.createCharString(
-              castNonNull(value).getValue(), charsetName, POS);
-        }
-      }
-      // Create a string without specifying a charset
+    case CHARACTER:
       return SqlLiteral.createCharString((String) castNonNull(literal.getValue2()), POS);
-    }
     case NUMERIC:
     case EXACT_NUMERIC: {
       if (SqlTypeName.APPROX_TYPES.contains(typeName)) {
diff --git a/core/src/test/java/org/apache/calcite/rel/rel2sql/RelToSqlConverterTest.java b/core/src/test/java/org/apache/calcite/rel/rel2sql/RelToSqlConverterTest.java
index cb3910e38b3..e85f1eef362 100644
--- a/core/src/test/java/org/apache/calcite/rel/rel2sql/RelToSqlConverterTest.java
+++ b/core/src/test/java/org/apache/calcite/rel/rel2sql/RelToSqlConverterTest.java
@@ -83,7 +83,6 @@
 import org.apache.calcite.tools.RelBuilder;
 import org.apache.calcite.tools.RuleSet;
 import org.apache.calcite.tools.RuleSets;
-import org.apache.calcite.util.ConversionUtil;
 import org.apache.calcite.util.ImmutableBitSet;
 import org.apache.calcite.util.TestUtil;
 import org.apache.calcite.util.Util;
@@ -289,17 +288,6 @@ private static String toSql(RelNode root, SqlDialect dialect,
     sql(query).ok(expected);
   }
 
-  /** Test case for <a href="https://issues.apache.org/jira/browse/CALCITE-6006">[CALCITE-6006]</a>
-   * RelToSqlConverter loses charset information. */
-  @Test void testCharset() {
-    sql("select _UTF8'\u4F60\u597D'")
-        .withMysql() // produces a simpler output query
-        .ok("SELECT _UTF-8'\u4F60\u597D'");
-    sql("select _UTF16'" + ConversionUtil.TEST_UNICODE_STRING + "'")
-        .withMysql()
-        .ok("SELECT _UTF-16LE'" + ConversionUtil.TEST_UNICODE_STRING + "'");
-  }
-
   /** Test case for
    * <a href="https://issues.apache.org/jira/browse/CALCITE-4321">[CALCITE-4321]
    * JDBC adapter omits FILTER (WHERE ...) expressions when generating SQL</a>