ESQL: Add ser/deser to functions tests

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/tree/Source.java

@@ -105,6 +105,10 @@ public String toString() {
         return text + location;
     }
 
+    /**
+     * @deprecated Sources created by this can't be correctly deserialized. For use in tests only.
+     */
+    @Deprecated
     public static Source synthetic(String text) {
         return new Source(Location.EMPTY, text);
     }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/AbstractFunctionTestCase.java

@@ -64,6 +64,7 @@
 import org.elasticsearch.xpack.esql.expression.predicate.operator.comparison.LessThan;
 import org.elasticsearch.xpack.esql.expression.predicate.operator.comparison.LessThanOrEqual;
 import org.elasticsearch.xpack.esql.expression.predicate.operator.comparison.NotEquals;
+import org.elasticsearch.xpack.esql.io.stream.PlanStreamOutput;
 import org.elasticsearch.xpack.esql.optimizer.rules.logical.FoldNull;
 import org.elasticsearch.xpack.esql.parser.ExpressionBuilder;
 import org.elasticsearch.xpack.esql.planner.Layout;
@@ -102,6 +103,7 @@
 import static org.elasticsearch.xpack.esql.EsqlTestUtils.randomLiteral;
 import static org.elasticsearch.xpack.esql.EsqlTestUtils.unboundLogicalOptimizerContext;
 import static org.elasticsearch.xpack.esql.SerializationTestUtils.assertSerialization;
+import static org.elasticsearch.xpack.esql.SerializationTestUtils.serializeDeserialize;
 import static org.elasticsearch.xpack.esql.expression.function.EsqlFunctionRegistry.mapParam;
 import static org.elasticsearch.xpack.esql.expression.function.EsqlFunctionRegistry.param;
 import static org.elasticsearch.xpack.esql.expression.function.EsqlFunctionRegistry.paramWithoutAnnotation;
@@ -331,7 +333,7 @@ protected static String typeErrorMessage(
         String ordinal = includeOrdinal ? TypeResolutions.ParamOrdinal.fromIndex(badArgPosition).name().toLowerCase(Locale.ROOT) + " " : "";
         String expectedTypeString = expectedTypeSupplier.apply(validPerPosition.get(badArgPosition), badArgPosition);
         String name = types.get(badArgPosition).typeName();
-        return ordinal + "argument of [] must be [" + expectedTypeString + "], found value [" + name + "] type [" + name + "]";
+        return ordinal + "argument of [source] must be [" + expectedTypeString + "], found value [" + name + "] type [" + name + "]";
     }
 
     @FunctionalInterface
@@ -522,7 +524,7 @@ public static Expression deepCopyOfField(String name, DataType type) {
      * <strong>except</strong> those that have been marked with {@link TestCaseSupplier.TypedData#forceLiteral()}.
      */
     protected final Expression buildFieldExpression(TestCaseSupplier.TestCase testCase) {
-        return build(testCase.getSource(), testCase.getDataAsFields());
+        return randomSerializeDeserialize(build(testCase.getSource(), testCase.getDataAsFields()));
     }
 
     /**
@@ -531,12 +533,47 @@ protected final Expression buildFieldExpression(TestCaseSupplier.TestCase testCa
      * those that have been marked with {@link TestCaseSupplier.TypedData#forceLiteral()}.
      */
     protected final Expression buildDeepCopyOfFieldExpression(TestCaseSupplier.TestCase testCase) {
+        // We don't use `randomSerializeDeserialize()` here as the deep copied fields aren't deserializable right now
         return build(testCase.getSource(), testCase.getDataAsDeepCopiedFields());
     }
 
+    private Expression randomSerializeDeserialize(Expression expression) {
+        if (randomBoolean()) {
+            return expression;
+        }
+
+        return serializeDeserializeExpression(expression);
+    }
+
+    /**
+     * Returns the expression after being serialized and deserialized.
+     * <p>
+     *     Tests randomly go through this method to ensure that the function retains the same logic after serialization and deserialization.
+     * </p>
+     * <p>
+     *     Can be overridden to provide custom serialization and deserialization logic, or disable it if needed.
+     * </p>
+    */
+    protected Expression serializeDeserializeExpression(Expression expression) {
+        Expression newExpression = serializeDeserialize(
+            expression,
+            PlanStreamOutput::writeNamedWriteable,
+            in -> in.readNamedWriteable(Expression.class),
+            testCase.getConfiguration() // The configuration query should be == to the source text of the function for this to work
+        );
+
+        // Fields use synthetic sources, which can't be serialized. So we replace with the originals instead.
+        var dummyChildren = newExpression.children()
+            .stream()
+            .<Expression>map(c -> new Literal(Source.EMPTY, "anything that won't match any test case", c.dataType()))
+            .toList();
+        // We first replace them with other unrelated expressions to force a replace, as some replaceChildren() will check for equality
+        return newExpression.replaceChildrenSameSize(dummyChildren).replaceChildrenSameSize(expression.children());
+    }
+
     protected final Expression buildLiteralExpression(TestCaseSupplier.TestCase testCase) {
         assumeTrue("Data can't be converted to literals", testCase.canGetDataAsLiterals());
-        return build(testCase.getSource(), testCase.getDataAsLiterals());
+        return randomSerializeDeserialize(build(testCase.getSource(), testCase.getDataAsLiterals()));
     }
 
     public static EvaluatorMapper.ToEvaluator toEvaluator() {
@@ -711,7 +748,7 @@ private static BytesRef randomizeBytesRefOffset(BytesRef bytesRef) {
     }
 
     public void testSerializationOfSimple() {
-        assertSerialization(buildFieldExpression(testCase));
+        assertSerialization(buildFieldExpression(testCase), testCase.getConfiguration());
     }
 
     /**

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/AbstractScalarFunctionTestCase.java

@@ -401,8 +401,8 @@ protected static TestCaseSupplier arithmeticExceptionOverflowCase(
                 evaluator + "[lhs=Attribute[channel=0], rhs=Attribute[channel=1]]",
                 dataType,
                 is(nullValue())
-            ).withWarning("Line -1:-1: evaluation of [] failed, treating result as null. Only first 20 failures recorded.")
-                .withWarning("Line -1:-1: java.lang.ArithmeticException: " + typeNameOverflow)
+            ).withWarning("Line 1:1: evaluation of [source] failed, treating result as null. Only first 20 failures recorded.")
+                .withWarning("Line 1:1: java.lang.ArithmeticException: " + typeNameOverflow)
         );
     }
 }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/TestCaseSupplier.java

@@ -16,12 +16,15 @@
 import org.elasticsearch.logging.LogManager;
 import org.elasticsearch.logging.Logger;
 import org.elasticsearch.test.ESTestCase;
+import org.elasticsearch.xpack.esql.EsqlTestUtils;
 import org.elasticsearch.xpack.esql.core.expression.Expression;
 import org.elasticsearch.xpack.esql.core.expression.Literal;
 import org.elasticsearch.xpack.esql.core.expression.MapExpression;
+import org.elasticsearch.xpack.esql.core.tree.Location;
 import org.elasticsearch.xpack.esql.core.tree.Source;
 import org.elasticsearch.xpack.esql.core.type.DataType;
 import org.elasticsearch.xpack.esql.core.util.NumericUtils;
+import org.elasticsearch.xpack.esql.session.Configuration;
 import org.elasticsearch.xpack.versionfield.Version;
 import org.hamcrest.Matcher;
 
@@ -54,6 +57,9 @@ public record TestCaseSupplier(String name, List<DataType> types, Supplier<TestC
     implements
         Supplier<TestCaseSupplier.TestCase> {
 
+    public static final Source TEST_SOURCE = new Source(new Location(1, 0), "source");
+    public static final Configuration TEST_CONFIGURATION = EsqlTestUtils.configuration(TEST_SOURCE.text());
+
     private static final Logger logger = LogManager.getLogger(TestCaseSupplier.class);
 
     /**
@@ -1388,6 +1394,10 @@ public static final class TestCase {
          * The {@link Source} this test case should be run with
          */
         private final Source source;
+        /**
+         * The {@link Configuration} this test case should use
+         */
+        private final Configuration configuration;
         /**
          * The parameter values and types to pass into the function for this test run
          */
@@ -1490,7 +1500,8 @@ public static TestCase typeError(List<TypedData> data, String expectedTypeError)
             Object extra,
             boolean canBuildEvaluator
         ) {
-            this.source = Source.EMPTY;
+            this.source = TEST_SOURCE;
+            this.configuration = TEST_CONFIGURATION;
             this.data = data;
             this.evaluatorToString = evaluatorToString;
             this.expectedType = expectedType == null ? null : expectedType.noText();
@@ -1510,6 +1521,10 @@ public Source getSource() {
             return source;
         }
 
+        public Configuration getConfiguration() {
+            return configuration;
+        }
+
         public List<TypedData> getData() {
             return data;
         }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/aggregate/TopTests.java

@@ -241,7 +241,7 @@ public static Iterable<Object[]> parameters() {
                             new TestCaseSupplier.TypedData(0, DataType.INTEGER, "limit").forceLiteral(),
                             new TestCaseSupplier.TypedData(new BytesRef("desc"), DataType.KEYWORD, "order").forceLiteral()
                         ),
-                        "Limit must be greater than 0 in [], found [0]"
+                        "Limit must be greater than 0 in [source], found [0]"
                     )
                 ),
                 new TestCaseSupplier(
@@ -252,7 +252,7 @@ public static Iterable<Object[]> parameters() {
                             new TestCaseSupplier.TypedData(2, DataType.INTEGER, "limit").forceLiteral(),
                             new TestCaseSupplier.TypedData(new BytesRef("wrong-order"), DataType.KEYWORD, "order").forceLiteral()
                         ),
-                        "Invalid order value in [], expected [ASC, DESC] but got [wrong-order]"
+                        "Invalid order value in [source], expected [ASC, DESC] but got [wrong-order]"
                     )
                 ),
                 new TestCaseSupplier(
@@ -263,7 +263,7 @@ public static Iterable<Object[]> parameters() {
                             new TestCaseSupplier.TypedData(null, DataType.INTEGER, "limit").forceLiteral(),
                             new TestCaseSupplier.TypedData(new BytesRef("desc"), DataType.KEYWORD, "order").forceLiteral()
                         ),
-                        "second argument of [] cannot be null, received [limit]"
+                        "second argument of [source] cannot be null, received [limit]"
                     )
                 ),
                 new TestCaseSupplier(
@@ -274,7 +274,7 @@ public static Iterable<Object[]> parameters() {
                             new TestCaseSupplier.TypedData(1, DataType.INTEGER, "limit").forceLiteral(),
                             new TestCaseSupplier.TypedData(null, DataType.KEYWORD, "order").forceLiteral()
                         ),
-                        "third argument of [] cannot be null, received [order]"
+                        "third argument of [source] cannot be null, received [order]"
                     )
                 )
             )
@@ -317,4 +317,10 @@ private static TestCaseSupplier makeSupplier(
             );
         });
     }
+
+    @Override
+    protected Expression serializeDeserializeExpression(Expression expression) {
+        // TODO: This aggregation doesn't serialize the Source, and must be fixed.
+        return expression;
+    }
 }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/fulltext/MatchTests.java

@@ -19,11 +19,13 @@
 import org.elasticsearch.xpack.esql.core.type.DataType;
 import org.elasticsearch.xpack.esql.expression.function.FunctionName;
 import org.elasticsearch.xpack.esql.expression.function.TestCaseSupplier;
+import org.elasticsearch.xpack.esql.io.stream.PlanStreamOutput;
 
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Supplier;
 
+import static org.elasticsearch.xpack.esql.SerializationTestUtils.serializeDeserialize;
 import static org.elasticsearch.xpack.esql.core.type.DataType.BOOLEAN;
 import static org.elasticsearch.xpack.esql.core.type.DataType.KEYWORD;
 import static org.elasticsearch.xpack.esql.core.type.DataType.UNSUPPORTED;
@@ -83,4 +85,19 @@ protected Expression build(Source source, List<Expression> args) {
         }
         return match;
     }
+
+    /**
+     * Copy of the overridden method that doesn't check for children size, as the {@code options} child isn't serialized in Match.
+     */
+    @Override
+    protected Expression serializeDeserializeExpression(Expression expression) {
+        Expression newExpression = serializeDeserialize(
+            expression,
+            PlanStreamOutput::writeNamedWriteable,
+            in -> in.readNamedWriteable(Expression.class),
+            testCase.getConfiguration() // The configuration query should be == to the source text of the function for this to work
+        );
+        // Fields use synthetic sources, which can't be serialized. So we use the originals instead.
+        return newExpression.replaceChildren(expression.children());
+    }
 }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/scalar/AbstractConfigurationFunctionTestCase.java

@@ -8,7 +8,6 @@
 package org.elasticsearch.xpack.esql.expression.function.scalar;
 
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.xpack.esql.EsqlTestUtils;
 import org.elasticsearch.xpack.esql.core.expression.Expression;
 import org.elasticsearch.xpack.esql.core.tree.Source;
 import org.elasticsearch.xpack.esql.core.util.StringUtils;
@@ -27,10 +26,22 @@ public abstract class AbstractConfigurationFunctionTestCase extends AbstractScal
 
     @Override
     protected Expression build(Source source, List<Expression> args) {
-        return buildWithConfiguration(source, args, EsqlTestUtils.TEST_CFG);
+        return buildWithConfiguration(source, args, testCase.getConfiguration());
     }
 
-    static Configuration randomConfiguration() {
+    public void testSerializationWithConfiguration() {
+        Configuration config = randomConfiguration();
+        Expression expr = buildWithConfiguration(testCase.getSource(), testCase.getDataAsFields(), config);
+
+        assertSerialization(expr, config);
+
+        Configuration differentConfig = randomValueOtherThan(config, AbstractConfigurationFunctionTestCase::randomConfiguration);
+
+        Expression differentExpr = buildWithConfiguration(testCase.getSource(), testCase.getDataAsFields(), differentConfig);
+        assertNotEquals(expr, differentExpr);
+    }
+
+    private static Configuration randomConfiguration() {
         // TODO: Randomize the query and maybe the pragmas.
         return new Configuration(
             randomZone(),
@@ -47,19 +58,4 @@ static Configuration randomConfiguration() {
             randomBoolean()
         );
     }
-
-    public void testSerializationWithConfiguration() {
-        Configuration config = randomConfiguration();
-        Expression expr = buildWithConfiguration(testCase.getSource(), testCase.getDataAsFields(), config);
-
-        assertSerialization(expr, config);
-
-        Configuration differentConfig;
-        do {
-            differentConfig = randomConfiguration();
-        } while (config.equals(differentConfig));
-
-        Expression differentExpr = buildWithConfiguration(testCase.getSource(), testCase.getDataAsFields(), differentConfig);
-        assertFalse(expr.equals(differentExpr));
-    }
 }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/scalar/convert/FromAggregateMetricDoubleTests.java

@@ -75,4 +75,10 @@ public static Iterable<Object[]> parameters() {
             )
         );
     }
+
+    @Override
+    protected Expression serializeDeserializeExpression(Expression expression) {
+        // AggregateMetricDoubleLiteral can't be serialized when it's a literal
+        return expression;
+    }
 }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/scalar/convert/ToCartesianPointTests.java

@@ -49,8 +49,8 @@ public static Iterable<Object[]> parameters() {
             bytesRef -> {
                 var exception = expectThrows(Exception.class, () -> CARTESIAN.wktToWkb(bytesRef.utf8ToString()));
                 return List.of(
-                    "Line -1:-1: evaluation of [] failed, treating result as null. Only first 20 failures recorded.",
-                    "Line -1:-1: " + exception
+                    "Line 1:1: evaluation of [source] failed, treating result as null. Only first 20 failures recorded.",
+                    "Line 1:1: " + exception
                 );
             }
         );

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/scalar/convert/ToCartesianShapeTests.java

@@ -50,8 +50,8 @@ public static Iterable<Object[]> parameters() {
             bytesRef -> {
                 var exception = expectThrows(Exception.class, () -> CARTESIAN.wktToWkb(bytesRef.utf8ToString()));
                 return List.of(
-                    "Line -1:-1: evaluation of [] failed, treating result as null. Only first 20 failures recorded.",
-                    "Line -1:-1: " + exception
+                    "Line 1:1: evaluation of [source] failed, treating result as null. Only first 20 failures recorded.",
+                    "Line 1:1: " + exception
                 );
             }
         );