DATAMONGO-2571 - Fix regular expression parameter binding for String-based queries.

Original pull request: #873.

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

@@ -229,7 +229,7 @@ public class ParameterBindingJsonReader extends AbstractBsonReader {
 			case REGULAR_EXPRESSION:
 
 				setCurrentBsonType(BsonType.REGULAR_EXPRESSION);
-				currentValue = bindableValueFor(token).getValue().toString();
+				currentValue = bindableValueFor(token).getValue();
 				break;
 			case STRING:
 
@@ -365,8 +365,11 @@ public class ParameterBindingJsonReader extends AbstractBsonReader {
 			return null;
 		}
 
+		boolean isRegularExpression = token.getType().equals(JsonTokenType.REGULAR_EXPRESSION);
+
 		BindableValue bindableValue = new BindableValue();
-		String tokenValue = String.class.cast(token.getValue());
+		String tokenValue = isRegularExpression ? token.getValue(BsonRegularExpression.class).getPattern()
+				: String.class.cast(token.getValue());
 		Matcher matcher = PARAMETER_BINDING_PATTERN.matcher(tokenValue);
 
 		if (token.getType().equals(JsonTokenType.UNQUOTED_STRING)) {
@@ -406,8 +409,6 @@ public class ParameterBindingJsonReader extends AbstractBsonReader {
 
 		String computedValue = tokenValue;
 
-
-
 		Matcher regexMatcher = EXPRESSION_BINDING_PATTERN.matcher(computedValue);
 
 		while (regexMatcher.find()) {
@@ -437,9 +438,15 @@ public class ParameterBindingJsonReader extends AbstractBsonReader {
 			computedValue = computedValue.replace(group, nullSafeToString(getBindableValueForIndex(index)));
 		}
 
-		bindableValue.setValue(computedValue);
-		bindableValue.setType(BsonType.STRING);
+		if (isRegularExpression) {
 
+			bindableValue.setValue(new BsonRegularExpression(computedValue));
+			bindableValue.setType(BsonType.REGULAR_EXPRESSION);
+		} else {
+
+			bindableValue.setValue(computedValue);
+			bindableValue.setType(BsonType.STRING);
+		}
 		return bindableValue;
 	}
 

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

@@ -333,6 +333,22 @@ class ParameterBindingJsonReaderUnitTests {
 						new Document("user.supervisor", "wonderwoman"))));
 	}
 
+	@Test // DATAMONGO-2571
+	public void shouldParseRegexCorrectly() {
+
+		Document target = parse("{ $and: [{'fieldA': {$in: [/ABC.*/, /CDE.*F/]}}, {'fieldB': {$ne: null}}]}");
+		assertThat(target)
+				.isEqualTo(Document.parse("{ $and: [{'fieldA': {$in: [/ABC.*/, /CDE.*F/]}}, {'fieldB': {$ne: null}}]}"));
+	}
+
+	@Test // DATAMONGO-2571
+	public void shouldParseRegexWithPlaceholderCorrectly() {
+
+		Document target = parse("{ $and: [{'fieldA': {$in: [/?0.*/, /CDE.*F/]}}, {'fieldB': {$ne: null}}]}", "ABC");
+		assertThat(target)
+				.isEqualTo(Document.parse("{ $and: [{'fieldA': {$in: [/ABC.*/, /CDE.*F/]}}, {'fieldB': {$ne: null}}]}"));
+	}
+
 	private static Document parse(String json, Object... args) {
 
 		ParameterBindingJsonReader reader = new ParameterBindingJsonReader(json, args);