DATAMONGO-2545 - Fix full Query Document binding resulting from SpEL.

We reenabled annotated queries using a SpEL expression resulting in the actual query document.

Original pull request: #864.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/util/json/ParameterBindingDocumentCodec.java

@@ -38,6 +38,7 @@ import org.bson.Document;
 import org.bson.Transformer;
 import org.bson.codecs.*;
 import org.bson.codecs.configuration.CodecRegistry;
+import org.bson.json.JsonParseException;
 import org.springframework.data.spel.EvaluationContextProvider;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.lang.Nullable;
@@ -190,9 +191,26 @@ public class ParameterBindingDocumentCodec implements CollectibleCodec<Document>
 
 		Document document = new Document();
 		reader.readStartDocument();
-		while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
-			String fieldName = reader.readName();
-			document.put(fieldName, readValue(reader, decoderContext));
+
+		try {
+
+			while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
+				String fieldName = reader.readName();
+				Object value = readValue(reader, decoderContext);
+				document.put(fieldName, value);
+			}
+		} catch (JsonParseException e) {
+			try {
+
+				Object value = readValue(reader, decoderContext);
+				if (value instanceof Map) {
+					if (!((Map) value).isEmpty()) {
+						return new Document((Map) value);
+					}
+				}
+			} catch (Exception ex) {
+				throw e;
+			}
 		}
 
 		reader.readEndDocument();

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/util/json/ParameterBindingJsonReader.java

@@ -25,6 +25,7 @@ import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.Locale;
+import java.util.Map;
 import java.util.TimeZone;
 import java.util.function.Supplier;
 import java.util.regex.Matcher;
@@ -495,6 +496,9 @@ public class ParameterBindingJsonReader extends AbstractBsonReader {
 		if (ClassUtils.isAssignable(Iterable.class, type)) {
 			return BsonType.ARRAY;
 		}
+		if (ClassUtils.isAssignable(Map.class, type)) {
+			return BsonType.DOCUMENT;
+		}
 
 		return BsonType.UNDEFINED;
 	}

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/util/json/ParameterBindingJsonReaderUnitTests.java

@@ -17,6 +17,9 @@ package org.springframework.data.mongodb.util.json;
 
 import static org.assertj.core.api.Assertions.*;
 
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Collections;
@@ -310,6 +313,26 @@ public class ParameterBindingJsonReaderUnitTests {
 		assertThat(target).isEqualTo(new Document("isBatman", "nooo"));
 	}
 
+	@Test // DATAMONGO-2545
+	void evaluatesSpelExpressionDefiningEntireQuery() {
+
+		Object[] args = new Object[] {};
+		StandardEvaluationContext evaluationContext = (StandardEvaluationContext) EvaluationContextProvider.DEFAULT
+				.getEvaluationContext(args);
+		evaluationContext.setRootObject(new DummySecurityObject(new DummyWithId("wonderwoman")));
+
+		String json = "?#{  T(" + this.getClass().getName()
+				+ ").isBatman() ? {'_class': { '$eq' : 'region' }} : { '$and' : { {'_class': { '$eq' : 'region' } }, {'user.superviser':  principal.id } } } }";
+
+		ParameterBindingJsonReader reader = new ParameterBindingJsonReader(json,
+				new ParameterBindingContext((index) -> args[index], new SpelExpressionParser(), evaluationContext));
+		Document target = new ParameterBindingDocumentCodec().decode(reader, DecoderContext.builder().build());
+
+		assertThat(target)
+				.isEqualTo(new Document("$and", Arrays.asList(new Document("_class", new Document("$eq", "region")),
+						new Document("user.superviser", "wonderwoman"))));
+	}
+
 	private static Document parse(String json, Object... args) {
 
 		ParameterBindingJsonReader reader = new ParameterBindingJsonReader(json, args);
@@ -321,4 +344,16 @@ public class ParameterBindingJsonReaderUnitTests {
 		return false;
 	}
 
+	@Data
+	@AllArgsConstructor
+	public static class DummySecurityObject {
+		DummyWithId principal;
+	}
+
+	@Data
+	@AllArgsConstructor
+	public static class DummyWithId {
+		String id;
+	}
+
 }