#335: Uses Locale.ROOT for converting strings to upper/lower case

doc/changes/changes_18.0.3.md

@@ -0,0 +1,11 @@
+# Common Module of Exasol Virtual Schemas Adapters 18.0.3, released 2026-06-08
+
+Code name: Fix locale-dependent request serialization
+
+## Summary
+
+This release consistently uses `Locale.ROOT` for converting strings to upper/lower case. This avoids locale dependent bugs.
+
+## Bugfixes
+
+* #335: Fixed incomplete `Locale.ROOT` hardening in request parsing and rendering. Locale-sensitive casing is now avoided when parsing table metadata and `IS JSON` constraints, and when rendering pushdown JSON for node types, data types, character sets, and join types.

pom.xml

@@ -2,7 +2,7 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <artifactId>virtual-schema-common-java</artifactId>
-    <version>18.0.2</version>
+    <version>18.0.3</version>
     <name>Common module of Exasol Virtual Schemas Adapters</name>
     <description>This is one of the modules of Virtual Schemas Adapters. The libraries provided by this project are the
         foundation of the adapter development, i.e. adapters must be implemented on top of them.</description>
@@ -93,7 +93,7 @@
     <parent>
         <artifactId>virtual-schema-common-java-generated-parent</artifactId>
         <groupId>com.exasol</groupId>
-        <version>18.0.2</version>
+        <version>18.0.3</version>
         <relativePath>pk_generated_parent.pom</relativePath>
     </parent>
 </project>

src/main/java/com/exasol/adapter/request/parser/TablesMetadataParser.java

@@ -2,8 +2,7 @@
 
 import static com.exasol.adapter.request.parser.RequestParserConstants.*;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.*;
 
 import com.exasol.adapter.metadata.*;
 import com.exasol.adapter.metadata.converter.SchemaMetadataJsonConverter;
@@ -222,7 +221,7 @@ private static DataType.IntervalType intervalTypeFromString(final String interva
     }
 
     private DataType getDataType(final JsonObject dataType, final String columnDescription) {
-        final String typeName = requireString(dataType, "type", columnDescription + " data type").toUpperCase();
+        final String typeName = requireString(dataType, "type", columnDescription + " data type").toUpperCase(Locale.ROOT);
         switch (typeName) {
             case "DECIMAL":
                 return getDecimalDataType(dataType);

src/main/java/com/exasol/adapter/request/renderer/PushdownSqlRenderer.java

@@ -3,6 +3,7 @@
 import static com.exasol.adapter.request.RequestJsonKeys.*;
 
 import java.util.List;
+import java.util.Locale;
 import java.util.Optional;
 
 import com.exasol.adapter.AdapterException;
@@ -58,7 +59,7 @@ public JsonObject visit(final SqlStatementSelect select) throws AdapterException
         }
 
         private JsonObjectBuilder createObjectBuilderFor(final SqlNode type) {
-            return JSON.createObjectBuilder().add(TYPE, type.getType().name().toLowerCase());
+            return JSON.createObjectBuilder().add(TYPE, type.getType().name().toLowerCase(Locale.ROOT));
         }
 
         private void addIfPresent(final SqlNode node, final String key, final JsonObjectBuilder builder)
@@ -159,15 +160,15 @@ public JsonObject visit(final SqlFunctionScalarCast function) throws AdapterExce
         private JsonObject render(final DataType dataType) {
             final JsonObjectBuilder builder = JSON.createObjectBuilder();
             final DataType.ExaDataType type = dataType.getExaDataType();
-            builder.add(TYPE, type.name().toUpperCase());
+            builder.add(TYPE, type.name().toUpperCase(Locale.ROOT));
             switch (type) {
                 case DECIMAL:
                     builder.add(PRECISION, dataType.getPrecision());
                     builder.add(SCALE, dataType.getScale());
                     break;
                 case VARCHAR:
                 case CHAR:
-                    builder.add(CHARACTER_SET, dataType.getCharset().name().toLowerCase());
+                    builder.add(CHARACTER_SET, dataType.getCharset().name().toLowerCase(Locale.ROOT));
                     builder.add(SIZE, dataType.getSize());
                     break;
                 case TIMESTAMP:
@@ -462,7 +463,7 @@ public JsonObject visit(final SqlJoin sqlJoin) throws AdapterException {
             builder.add(LEFT, sqlJoin.getLeft().accept(this));
             builder.add(RIGHT, sqlJoin.getRight().accept(this));
             builder.add(CONDITION, sqlJoin.getCondition().accept(this));
-            builder.add(JOIN_TYPE, sqlJoin.getJoinType().name().toLowerCase());
+            builder.add(JOIN_TYPE, sqlJoin.getJoinType().name().toLowerCase(Locale.ROOT));
             return builder.build();
         }
 

src/main/java/com/exasol/adapter/sql/AbstractSqlPredicateJson.java

@@ -1,7 +1,6 @@
 package com.exasol.adapter.sql;
 
-import java.util.Arrays;
-import java.util.List;
+import java.util.*;
 
 /**
  * This class contains a common behavior for the {@link SqlNodeType#PREDICATE_IS_JSON} and
@@ -15,11 +14,11 @@ public abstract class AbstractSqlPredicateJson extends SqlPredicate {
     /**
      * The Type constraint.
      */
-    protected final SqlPredicateIsJson.TypeConstraints typeConstraint;
+    protected final TypeConstraints typeConstraint;
     /**
      * The Key uniqueness constraint.
      */
-    protected final SqlPredicateIsJson.KeyUniquenessConstraint keyUniquenessConstraint;
+    protected final KeyUniquenessConstraint keyUniquenessConstraint;
 
     /**
      * Instantiates a new Abstract sql predicate json.
@@ -29,9 +28,8 @@ public abstract class AbstractSqlPredicateJson extends SqlPredicate {
      * @param typeConstraint          the type constraint
      * @param keyUniquenessConstraint the key uniqueness constraint
      */
-    public AbstractSqlPredicateJson(final Predicate predicate, final SqlNode expression,
-            final SqlPredicateIsJson.TypeConstraints typeConstraint,
-            final SqlPredicateIsJson.KeyUniquenessConstraint keyUniquenessConstraint) {
+    protected AbstractSqlPredicateJson(final Predicate predicate, final SqlNode expression, final TypeConstraints typeConstraint,
+            final KeyUniquenessConstraint keyUniquenessConstraint) {
         super(predicate);
         this.expression = expression;
         this.typeConstraint = typeConstraint;
@@ -117,12 +115,14 @@ public String toString() {
          * @param value the value
          * @return the sql predicate is json . key uniqueness constraint
          */
-        public static SqlPredicateIsJson.KeyUniquenessConstraint of(final String value) {
-            final String formattedValue = String.join("_", value.split(" ")).toUpperCase();
-            return SqlPredicateIsJson.KeyUniquenessConstraint.valueOf(formattedValue);
+        public static KeyUniquenessConstraint of(final String value) {
+            final String formattedValue = String.join("_", value.split(" ")).toUpperCase(Locale.ROOT);
+            return KeyUniquenessConstraint.valueOf(formattedValue);
         }
     }
 
     @Override
-    public List<SqlNode> getChildren() { return Arrays.asList(this.expression); }
+    public List<SqlNode> getChildren() {
+        return Arrays.asList(this.expression);
+    }
 }

src/test/java/com/exasol/adapter/request/parser/PushDownSqlParserTest.java

@@ -25,6 +25,7 @@
 
 import com.exasol.adapter.metadata.*;
 import com.exasol.adapter.sql.*;
+import com.exasol.test.locale.WithLocale;
 
 import jakarta.json.*;
 
@@ -537,24 +538,19 @@ void testParsePredicateIsNull() {
     }
 
     @Test
+    @WithLocale("tr")
     void testParsePredicateIsNullUsesLocaleIndependentUppercaseConversion() {
-        final Locale defaultLocale = Locale.getDefault();
-        try {
-            Locale.setDefault(Locale.forLanguageTag("tr"));
-            final String sqlAsJson = "{" //
-                    + "   \"type\" : \"predicate_is_null\", " //
-                    + "   \"expression\" : { " //
-                    + "        \"type\" : \"literal_double\", " //
-                    + "        \"value\" : \"0.0\" " //
-                    + "   } " //
-                    + "}";
-            final JsonObject jsonObject = createJsonObjectFromString(sqlAsJson);
-            final SqlPredicateIsNull sqlPredicateIsNull = (SqlPredicateIsNull) this.defaultParser
-                    .parseExpression(jsonObject);
-            assertThat(sqlPredicateIsNull.getType(), equalTo(PREDICATE_IS_NULL));
-        } finally {
-            Locale.setDefault(defaultLocale);
-        }
+        final String sqlAsJson = "{" //
+                + "   \"type\" : \"predicate_is_null\", " //
+                + "   \"expression\" : { " //
+                + "        \"type\" : \"literal_double\", " //
+                + "        \"value\" : \"0.0\" " //
+                + "   } " //
+                + "}";
+        final JsonObject jsonObject = createJsonObjectFromString(sqlAsJson);
+        final SqlPredicateIsNull sqlPredicateIsNull = (SqlPredicateIsNull) this.defaultParser
+                .parseExpression(jsonObject);
+        assertThat(sqlPredicateIsNull.getType(), equalTo(PREDICATE_IS_NULL));
     }
 
     @Test
@@ -665,47 +661,47 @@ void testParseFunctionScalarCastToTimestamp() {
 
     @Test
     void testGetDataTypeDecimal() {
-        assertThat(getDataType("{" 
-                + "   \"type\" : \"DECIMAL\", " 
-                + "   \"precision\" : 31, " 
-                + "   \"scale\" : 41 " 
+        assertThat(getDataType("{"
+                + "   \"type\" : \"DECIMAL\", "
+                + "   \"precision\" : 31, "
+                + "   \"scale\" : 41 "
                 + "}"), equalTo(createDecimal(31, 41)));
     }
 
     @Test
     void testGetDataTypeDouble() {
-        assertThat(getDataType("{" 
-                + "   \"type\" : \"DOUBLE\" " 
+        assertThat(getDataType("{"
+                + "   \"type\" : \"DOUBLE\" "
                 + "}"), equalTo(DataType.createDouble()));
     }
 
     @Test
     void testGetDataTypeChar() {
-        assertThat(getDataType("{" 
-                + "   \"type\" : \"CHAR\", " 
-                + "   \"size\" : 22 " 
+        assertThat(getDataType("{"
+                + "   \"type\" : \"CHAR\", "
+                + "   \"size\" : 22 "
                 + "}"), equalTo(DataType.createChar(22, UTF8)));
     }
 
     @Test
     void testGetDataTypeBoolean() {
-        assertThat(getDataType("{" 
-                + "   \"type\" : \"BOOLEAN\" " 
+        assertThat(getDataType("{"
+                + "   \"type\" : \"BOOLEAN\" "
                 + "}"), equalTo(DataType.createBool()));
     }
 
     @Test
     void testGetDataTypeDate() {
-        assertThat(getDataType("{" 
-                + "   \"type\" : \"DATE\" " 
+        assertThat(getDataType("{"
+                + "   \"type\" : \"DATE\" "
                 + "}"), equalTo(DataType.createDate()));
     }
 
     @Test
     void testGetDataTypeGeometry() {
-        assertThat(getDataType("{" 
-                + "   \"type\" : \"GEOMETRY\", " 
-                + "   \"srid\" : 42 " 
+        assertThat(getDataType("{"
+                + "   \"type\" : \"GEOMETRY\", "
+                + "   \"srid\" : 42 "
                 + "}"), equalTo(DataType.createGeometry(42)));
     }
 

src/test/java/com/exasol/adapter/request/parser/TablesMetadataParserTest.java

@@ -19,6 +19,7 @@
 import org.junit.jupiter.params.provider.MethodSource;
 
 import com.exasol.adapter.metadata.*;
+import com.exasol.test.locale.WithLocale;
 
 import jakarta.json.*;
 
@@ -191,6 +192,26 @@ void testParseMetadataReadsAdapterNotes() {
                         .identity(false).defaultValue("").comment("").build()));
     }
 
+    @Test
+    @WithLocale("tr")
+    void testParseMetadataUsesLocaleIndependentUppercaseConversion() {
+        final JsonArray tablesAsJson = arrayBuilder().add(objectBuilder()
+                .add("name", "T1")
+                .add("columns", arrayBuilder()
+                        .add(objectBuilder().add("name", "INTERVAL_COL")
+                                .add("dataType", objectBuilder().add("type", "interval").add("fromTo",
+                                        "YEAR TO MONTH")))))
+                .build();
+
+        final List<TableMetadata> tables = TablesMetadataParser.create().parse(tablesAsJson);
+
+        final List<ColumnMetadata> expectedColumns = List.of(ColumnMetadata.builder().name("INTERVAL_COL")
+                .adapterNotes("").type(DataType.createIntervalYearMonth(2)).nullable(true).identity(false)
+                .defaultValue("").comment("").build());
+
+        assertThat(tables, contains(new TableMetadata("T1", "", expectedColumns, "")));
+    }
+
     @ParameterizedTest
     @MethodSource("invalidTableMetadata")
     void testParseMetadataThrowsException(final JsonArray tablesAsJson,

src/test/java/com/exasol/adapter/request/renderer/PushdownSqlRendererTest.java

@@ -1,6 +1,7 @@
 package com.exasol.adapter.request.renderer;
 
 import static com.exasol.adapter.metadata.DataType.*;
+import static com.exasol.adapter.metadata.DataType.ExaCharset.ASCII;
 import static com.exasol.adapter.metadata.DataType.ExaCharset.UTF8;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.equalTo;
@@ -29,6 +30,7 @@
 import com.exasol.adapter.metadata.TableMetadata;
 import com.exasol.adapter.request.parser.PushdownSqlParser;
 import com.exasol.adapter.sql.*;
+import com.exasol.test.locale.WithLocale;
 
 import jakarta.json.*;
 
@@ -987,6 +989,51 @@ void testRenderDataTypeIntervalYearToMonth() {
                 () -> assertThat(rendered.getJsonObject("dataType").getString("fromTo"), equalTo("YEAR TO MONTH")));
     }
 
+    @Test
+    @WithLocale("tr")
+    void testRenderUsesLocaleIndependentLowercaseForJoinTypes() {
+        final JsonObject rendered = renderToJsonObject(new SqlJoin(new SqlTable("A", null), new SqlTable("B", null),
+                new SqlLiteralBool(true), JoinType.INNER));
+
+        assertAll(() -> assertThat(rendered.getString("type"), equalTo("join")),
+                () -> assertThat(rendered.getString("join_type"), equalTo("inner")));
+    }
+
+    @Test
+    @WithLocale("tr")
+    void testRenderUsesLocaleIndependentCharacterSetAndDataTypeNames() {
+        final JsonObject rendered = renderToJsonObject(
+                new SqlFunctionScalarCast(createVarChar(10, ASCII), new SqlLiteralString("dummy")));
+        final JsonObject dataType = rendered.getJsonObject("dataType");
+
+        assertAll(() -> assertThat(dataType.getString("type"), equalTo("VARCHAR")),
+                () -> assertThat(dataType.getString("characterSet"), equalTo("ascii")));
+    }
+
+    @Test
+    @WithLocale("tr")
+    void testRenderUsesLocaleIndependentUppercaseForDataTypeNames() {
+        final JsonObject rendered = renderToJsonObject(
+                new SqlFunctionScalarCast(createIntervalYearMonth(7), new SqlLiteralString("dummy")));
+        final JsonObject dataType = rendered.getJsonObject("dataType");
+
+        assertAll(() -> assertThat(dataType.getString("type"), equalTo("INTERVAL")),
+                () -> assertThat(dataType.getJsonNumber("precision").intValue(), equalTo(7)),
+                () -> assertThat(dataType.getString("fromTo"), equalTo("YEAR TO MONTH")));
+    }
+
+    @Test
+    @WithLocale("tr")
+    void testRenderUsesLocaleIndependentLowercaseForPredicateTypes() {
+        final JsonObject rendered = renderToJsonObject(new SqlPredicateIsJson(new SqlLiteralString("x"),
+                AbstractSqlPredicateJson.TypeConstraints.OBJECT,
+                AbstractSqlPredicateJson.KeyUniquenessConstraint.WITH_UNIQUE_KEYS));
+
+        assertAll(() -> assertThat(rendered.getString("type"), equalTo("predicate_is_json")),
+                () -> assertThat(rendered.getString("typeConstraint"), equalTo("OBJECT")),
+                () -> assertThat(rendered.getString("keyUniquenessConstraint"), equalTo("WITH UNIQUE KEYS")));
+    }
+
     private JsonObject renderToJsonObject(final SqlNode node) {
         return (JsonObject) new PushdownSqlRenderer().render(node);
     }