How to inject not null @RepositoryRestResource into @RestController

Question

In my GCP Endpoints project @RepositoryRestResource gets injected into the @RestController as null. As a result I get a NullPointer of course. How to inject the properly initiated repository into controller?

Repository class, controller, application and pom follow.

The repository:

package com.katamlek.gcp_crystalloids;

@RepositoryRestResource
public interface PostRepository extends DatastoreRepository<Post, Long> {
}

The controller.

package com.katamlek.gcp_crystalloids;

@Api
@RestController
public class PostController{

    @Autowired
    private PostRepository postRepository;

    // dummy
    @ApiMethod(path = "/hello", httpMethod = ApiMethod.HttpMethod.GET)
    public DummyClass hello() {
        return new DummyClass();
    }

    @ApiMethod(path = "/add", httpMethod = ApiMethod.HttpMethod.POST)
    public Post post(@RequestBody Post post) {
        return postRepository.save(post);
    }

...

And the pom.xml.

<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.katamlek</groupId>
    <artifactId>gcp_crystalloids</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>gcp_crystalloids</name>
    <description>Demo project for Crystalloids</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Hoxton.SR8</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-rest</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-gcp-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-gcp-starter-storage</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-gcp-data-datastore</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-gcp-starter-data-datastore</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>com.google.endpoints</groupId>
            <artifactId>endpoints-framework-all</artifactId>
            <version>2.2.1</version>
        </dependency>
        <dependency>
            <groupId>com.google.endpoints</groupId>
            <artifactId>endpoints-management-control-appengine-all</artifactId>
            <version>1.0.13</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>provided</scope>
        </dependency>
<!--        <dependency>-->
<!--            <groupId>javax.servlet</groupId>-->
<!--            <artifactId>javax.servlet-api</artifactId>-->
<!--            <version>3.1.0</version>-->
<!--            <type>jar</type>-->
<!--            <scope>provided</scope>-->
<!--        </dependency>-->
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>com.google.cloud.tools</groupId>
                <artifactId>endpoints-framework-maven-plugin</artifactId>
                <version>1.0.2</version>
                <configuration>
                    <!-- plugin configuration -->
                    <hostname>gcpcrystalloids.appspot.com</hostname>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

The application:

package com.katamlek.gcp_crystalloids;

@SpringBootApplication(scanBasePackages = {"com.katamlek"})
@EntityScan(basePackages = {"com.katamlek"})
@EnableDatastoreRepositories(basePackages = {"com.katamlek"})
public class GcpCrystalloidsApplication {

    public static void main(String[] args) {
        SpringApplication.run(GcpCrystalloidsApplication.class, args);
    }

}