1.9.x - PropertyPath is not dealing with properties containing underscore

[sabinewinkler]

Having an entity with an underscore property e.g. "first_name" and a related repository method "findByFirst__name" (as documented with double underscore - http://docs.spring.io/spring-data/jpa/docs/current/reference/html/#repositories.query-methods.query-property-expressions) results in the following exception:

java.lang.IllegalStateException: Failed to load ApplicationContext
at ....
Caused by: org.springframework.data.mapping.PropertyReferenceException: No property first found for type Todo!
at org.springframework.data.mapping.PropertyPath.<init>(PropertyPath.java:75)
at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:327)
at org.springframework.data.mapping.PropertyPath.create(PropertyPath.java:307)
at org.springframework.data.mapping.PropertyPath.from(PropertyPath.java:270)
at org.springframework.data.mapping.PropertyPath.from(PropertyPath.java:241)
at org.springframework.data.repository.query.parser.Part.<init>(Part.java:76)
at org.springframework.data.repository.query.parser.PartTree$OrPart.<init>(PartTree.java:235)
at org.springframework.data.repository.query.parser.PartTree$Predicate.buildTree(PartTree.java:373)
at org.springframework.data.repository.query.parser.PartTree$Predicate.<init>(PartTree.java:353)
at org.springframework.data.repository.query.parser.PartTree.<init>(PartTree.java:87)
at org.springframework.data.jpa.repository.query.PartTreeJpaQuery.<init>(PartTreeJpaQuery.java:61)
at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$CreateQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:94)
at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$CreateIfNotFoundQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:205)
at org.springframework.data.jpa.repository.query.JpaQueryLookupStrategy$AbstractQueryLookupStrategy.resolveQuery(JpaQueryLookupStrategy.java:72)
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.<init>(RepositoryFactorySupport.java:349)
at org.springframework.data.repository.core.support.RepositoryFactorySupport.getRepository(RepositoryFactorySupport.java:187)
at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.initAndReturn(RepositoryFactoryBeanSupport.java:239)
at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.afterPropertiesSet(RepositoryFactoryBeanSupport.java:225)
at org.springframework.data.jpa.repository.support.JpaRepositoryFactoryBean.afterPropertiesSet(JpaRepositoryFactoryBean.java:92)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1633)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1570)
... 40 more

Debugging this behaviour shows that the PropertyPath#from method seems not to deal with this case:

/**
 * Extracts the {@link PropertyPath} chain from the given source {@link String} and {@link TypeInformation}.
 * 
 * @param source must not be {@literal null}.
 * @param type
 * @return
 */
public static PropertyPath from(String source, TypeInformation<?> type) {

    Assert.hasText(source, "Source must not be null or empty!");
    Assert.notNull(type, "TypeInformation must not be null or empty!");

    List<String> iteratorSource = new ArrayList<String>();
    Matcher matcher = SPLITTER.matcher("_" + source);

    while (matcher.find()) {
        iteratorSource.add(matcher.group(1));
    }

    Iterator<String> parts = iteratorSource.iterator();

    PropertyPath result = null;
    Stack<PropertyPath> current = new Stack<PropertyPath>();

    while (parts.hasNext()) {
        if (result == null) {
            result = create(parts.next(), type, current);
            current.push(result);
        } else {
            current.push(create(parts.next(), current));
        }
    }

    return result;
}

Can you please check this. Thanks in advance!

[odrotbohm]

Creating a pull request for this was an accident, right? Id' rather turn this into a request to remove the relevant section from the reference documentation as fixing this basically opens up a can of worms (what about properties with multiple underscores?). We generally recommend following standard Java naming conventions, i.e. not using underscores in variable names.

[odrotbohm]

There's an open ticket in our bug tracker, which has a few more details on why supporting this would complicate things and why we think it's not worth the effort.

[sabinewinkler]

Right, it was an accident. Sorry for that. Thanks for the ticket hint. In this case can you please remove the corresponding part from the documentation and make it clear to the user why it is not supported.

[odrotbohm]

I've updated the ticket accordingly.