For #2038 - updated from 12.3.6 to 12.3.7 - NPE BeanDescriptor.findPropertyFromPath(BeanDescriptor.java:1965) (#2047)

* #2038 - lazy loading ToMany with path

* #2038 - Failing test for NPE BeanDescriptor.findPropertyFromPath(BeanDescriptor.java:1965)

* #2038 Refactor internals DbReadContext use BeanPropertyAssocMany

src/test/java/io/ebeaninternal/server/loadcontext/DLoadContextTest.java

@@ -5,6 +5,7 @@ import io.ebean.FetchConfig;
 import io.ebean.Query;
 import io.ebeaninternal.server.core.OrmQueryRequest;
 import io.ebeaninternal.server.core.OrmQueryRequestTestHelper;
+import io.ebeaninternal.server.deploy.BeanPropertyAssocMany;
 import org.tests.model.basic.Order;
 import org.junit.Test;
 
@@ -94,13 +95,14 @@ public class DLoadContextTest extends BaseTestCase {
   @Test
   public void construct_when_fetch_expect_100_100_batchSize() {
 
+    BeanPropertyAssocMany<?> many = (BeanPropertyAssocMany<?>)getBeanDescriptor(Order.class).getBeanProperty("details");
     // the fetch is converted to a query join due to the maxRows
     OrmQueryRequest<Order> queryRequest = queryRequest(query().fetch("details").setMaxRows(100));
     queryRequest.initTransIfRequired();
     queryRequest.endTransIfRequired();
 
     DLoadContext graphContext = (DLoadContext) queryRequest.getGraphContext();
-    DLoadManyContext details = graphContext.getManyContext("details");
+    DLoadManyContext details = graphContext.getManyContext("details", many);
 
     assertThat(details.firstBatchSize).isEqualTo(100);
     assertThat(details.secondaryBatchSize).isEqualTo(100);

src/test/java/org/tests/o2m/lazy/OmlBar.java

@@ -0,0 +1,37 @@
+package org.tests.o2m.lazy;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.OneToMany;
+import javax.persistence.Table;
+import java.util.ArrayList;
+import java.util.List;
+
+@Entity
+@Table(name = "oml_bar")
+public class OmlBar {
+
+  @Id
+  private Long id;
+
+  @OneToMany(mappedBy = "bar", cascade = CascadeType.ALL)
+  private List<OmlFoo> fooList = new ArrayList<OmlFoo>();
+
+  public Long getId() {
+    return id;
+  }
+
+  public void setId(Long id) {
+    this.id = id;
+  }
+
+  public List<OmlFoo> getFooList() {
+    return fooList;
+  }
+
+  public void setFooList(List<OmlFoo> fooList) {
+    this.fooList = fooList;
+  }
+
+}

src/test/java/org/tests/o2m/lazy/OmlBaz.java

@@ -0,0 +1,33 @@
+package org.tests.o2m.lazy;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.ManyToOne;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "oml_baz")
+public class OmlBaz {
+  @Id
+  private Long id;
+
+  @ManyToOne(optional = false)
+  private OmlFoo foo;
+
+  public Long getId() {
+    return id;
+  }
+
+  public void setId(Long id) {
+    this.id = id;
+  }
+
+  public OmlFoo getFoo() {
+    return foo;
+  }
+
+  public void setFoo(OmlFoo foo) {
+    this.foo = foo;
+  }
+
+}

src/test/java/org/tests/o2m/lazy/OmlFoo.java

@@ -0,0 +1,49 @@
+package org.tests.o2m.lazy;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.ManyToOne;
+import javax.persistence.OneToMany;
+import javax.persistence.Table;
+import java.util.ArrayList;
+import java.util.List;
+
+@Entity
+@Table(name = "oml_foo")
+public class OmlFoo {
+
+  @Id
+  private Long id;
+
+  @ManyToOne(optional = false)
+  private OmlBar bar;
+
+  @OneToMany(mappedBy = "foo", cascade = CascadeType.ALL)
+  private List<OmlBaz> bazList = new ArrayList<OmlBaz>();
+
+  public Long getId() {
+    return id;
+  }
+
+  public void setId(Long id) {
+    this.id = id;
+  }
+
+  public OmlBar getBar() {
+    return bar;
+  }
+
+  public void setBar(OmlBar bar) {
+    this.bar = bar;
+  }
+
+  public List<OmlBaz> getBazList() {
+    return bazList;
+  }
+
+  public void setBazList(List<OmlBaz> bazList) {
+    this.bazList = bazList;
+  }
+
+}

src/test/java/org/tests/o2m/lazy/TestLazyManyViaPath.java

@@ -0,0 +1,56 @@
+package org.tests.o2m.lazy;
+
+import io.ebean.BaseTestCase;
+import io.ebean.DB;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class TestLazyManyViaPath extends BaseTestCase {
+
+  @Test
+  public void test() {
+
+    OmlBar bar = new OmlBar();
+    List<OmlFoo> fooList = new ArrayList<>();
+    fooList.add(createNewFooWithBar(bar));
+
+    bar.setFooList(fooList);
+
+    DB.save(bar);
+
+    OmlFoo fooFromDb = DB
+      .find(OmlFoo.class)
+      .where()
+      .eq("id", bar.getFooList().get(0).getId())
+      .findOne();
+
+    // This works
+    List<OmlFoo> foosList = fooFromDb.getBar().getFooList();
+    assertThat(fooList.size()).isEqualTo(1);
+
+    OmlBaz bazFromDb = DB
+      .find(OmlBaz.class)
+      .where()
+      .eq("id", bar.getFooList().get(0).getBazList().get(0).getId())
+      .findOne();
+
+    // This does not work and gives the exception
+    List<OmlFoo> foosList1 = bazFromDb.getFoo().getBar().getFooList();
+    assertThat(foosList1.size()).isEqualTo(1);
+
+  }
+
+  private static OmlFoo createNewFooWithBar(OmlBar bar) {
+    OmlFoo foo = new OmlFoo();
+    foo.setBar(bar);
+    OmlBaz baz = new OmlBaz();
+    baz.setFoo(foo);
+    foo.getBazList().add(baz);
+    return foo;
+  }
+
+}