Create error response for concurrent modifications

scm-core/src/main/java/sonia/scm/ConcurrentModificationException.java

@@ -1,4 +1,34 @@
 package sonia.scm;
 
-public class ConcurrentModificationException extends Exception {
+import java.util.Collections;
+import java.util.List;
+
+import static java.util.Collections.unmodifiableList;
+import static java.util.stream.Collectors.joining;
+
+public class ConcurrentModificationException extends RuntimeException {
+  private final List<ContextEntry> context;
+
+  public ConcurrentModificationException(Class type, String id) {
+    this(Collections.singletonList(new ContextEntry(type, id)));
+  }
+
+  public ConcurrentModificationException(String type, String id) {
+    this(Collections.singletonList(new ContextEntry(type, id)));
+  }
+
+  private ConcurrentModificationException(List<ContextEntry> context) {
+    super(createMessage(context));
+    this.context = context;
+  }
+
+  public List<ContextEntry> getContext() {
+    return unmodifiableList(context);
+  }
+
+  private static String createMessage(List<ContextEntry> context) {
+    return context.stream()
+      .map(c -> c.getType().toLowerCase() + " with id " + c.getId())
+      .collect(joining(" in ", "", " has been modified concurrently"));
+  }
 }

scm-core/src/main/java/sonia/scm/NotFoundException.java

@@ -15,14 +15,15 @@ public class NotFoundException extends RuntimeException {
   private final List<ContextEntry> context;
 
   public NotFoundException(Class type, String id) {
-    this.context = Collections.singletonList(new ContextEntry(type, id));
+    this(Collections.singletonList(new ContextEntry(type, id)));
   }
 
   public NotFoundException(String type, String id) {
-    this.context = Collections.singletonList(new ContextEntry(type, id));
+    this(Collections.singletonList(new ContextEntry(type, id)));
   }
 
   private NotFoundException(List<ContextEntry> context) {
+    super(createMessage(context));
     this.context = context;
   }
 
@@ -46,8 +47,7 @@ public class NotFoundException extends RuntimeException {
     return unmodifiableList(context);
   }
 
-  @Override
+  private static String createMessage(List<ContextEntry> context) {
-  public String getMessage() {
     return context.stream()
       .map(c -> c.getType().toLowerCase() + " with id " + c.getId())
       .collect(joining(" in ", "could not find ", ""));

scm-test/src/main/java/sonia/scm/user/UserManagerTestBase.java

@@ -97,7 +97,7 @@ public abstract class UserManagerTestBase extends ManagerTestBase<User> {
   }
 
   @Test(expected = NotFoundException.class)
-  public void testDeleteNotFound() throws Exception {
+  public void testDeleteNotFound() {
     manager.delete(UserTestData.createDent());
   }
 
@@ -181,7 +181,7 @@ public abstract class UserManagerTestBase extends ManagerTestBase<User> {
   }
 
   @Test
-  public void testModify() throws AlreadyExistsException, NotFoundException, ConcurrentModificationException {
+  public void testModify() throws AlreadyExistsException {
     User zaphod = UserTestData.createZaphod();
 
     manager.create(zaphod);
@@ -238,7 +238,7 @@ public abstract class UserManagerTestBase extends ManagerTestBase<User> {
   }
 
   @Test
-  public void testRefresh() throws AlreadyExistsException, NotFoundException {
+  public void testRefresh() throws AlreadyExistsException {
     User zaphod = UserTestData.createZaphod();
 
     manager.create(zaphod);
@@ -299,7 +299,7 @@ public abstract class UserManagerTestBase extends ManagerTestBase<User> {
       return user;
     }
 
-    private void modifyAndDeleteUser(User user) throws IOException, NotFoundException, ConcurrentModificationException {
+    private void modifyAndDeleteUser(User user) {
       String name = user.getName();
       String nd = name.concat(" new displayname");
 

scm-webapp/src/main/java/sonia/scm/api/rest/ConcurrentModificationExceptionMapper.java

@@ -1,6 +1,8 @@
 package sonia.scm.api.rest;
 
 import sonia.scm.ConcurrentModificationException;
+import sonia.scm.api.v2.resources.ErrorDto;
+import sonia.scm.web.VndMediaType;
 
 import javax.ws.rs.core.Response;
 import javax.ws.rs.ext.ExceptionMapper;
@@ -10,6 +12,6 @@ import javax.ws.rs.ext.Provider;
 public class ConcurrentModificationExceptionMapper implements ExceptionMapper<ConcurrentModificationException> {
   @Override
   public Response toResponse(ConcurrentModificationException exception) {
-    return Response.status(Response.Status.CONFLICT).build();
+    return Response.status(Response.Status.CONFLICT).entity(ErrorDto.from(exception)).type(VndMediaType.ERROR_TYPE).build();
   }
 }

scm-webapp/src/main/java/sonia/scm/api/v2/resources/ErrorDto.java

@@ -3,6 +3,7 @@ package sonia.scm.api.v2.resources;
 import com.fasterxml.jackson.annotation.JsonInclude;
 import lombok.Getter;
 import org.slf4j.MDC;
+import sonia.scm.ConcurrentModificationException;
 import sonia.scm.ContextEntry;
 import sonia.scm.NotFoundException;
 
@@ -32,4 +33,8 @@ public class ErrorDto {
   static ErrorDto from(NotFoundException notFoundException) {
     return new ErrorDto(MDC.get("transaction_id"), "todo", notFoundException.getContext(), notFoundException.getMessage());
   }
+
+  public static ErrorDto from(ConcurrentModificationException concurrentModificationException) {
+    return new ErrorDto(MDC.get("transaction_id"), "todo", concurrentModificationException.getContext(), concurrentModificationException.getMessage());
+  }
 }

scm-webapp/src/main/java/sonia/scm/api/v2/resources/GroupResource.java

@@ -98,7 +98,7 @@ public class GroupResource {
     @ResponseCode(code = 500, condition = "internal server error")
   })
   @TypeHint(TypeHint.NO_CONTENT.class)
-  public Response update(@PathParam("id") String name, @Valid GroupDto groupDto) throws ConcurrentModificationException {
+  public Response update(@PathParam("id") String name, @Valid GroupDto groupDto) {
     return adapter.update(name, existing -> dtoToGroupMapper.map(groupDto));
   }
 }

scm-webapp/src/main/java/sonia/scm/api/v2/resources/IdResourceManagerAdapter.java

@@ -39,7 +39,7 @@ class IdResourceManagerAdapter<MODEL_OBJECT extends ModelObject,
     return singleAdapter.get(loadBy(id), mapToDto);
   }
 
-  public Response update(String id, Function<MODEL_OBJECT, MODEL_OBJECT> applyChanges) throws ConcurrentModificationException {
+  public Response update(String id, Function<MODEL_OBJECT, MODEL_OBJECT> applyChanges) {
     return singleAdapter.update(
       loadBy(id),
       applyChanges,

scm-webapp/src/main/java/sonia/scm/api/v2/resources/RepositoryResource.java

@@ -138,7 +138,7 @@ public class RepositoryResource {
     @ResponseCode(code = 500, condition = "internal server error")
   })
   @TypeHint(TypeHint.NO_CONTENT.class)
-  public Response update(@PathParam("namespace") String namespace, @PathParam("name") String name, @Valid RepositoryDto repositoryDto) throws ConcurrentModificationException {
+  public Response update(@PathParam("namespace") String namespace, @PathParam("name") String name, @Valid RepositoryDto repositoryDto) {
     return adapter.update(
       loadBy(namespace, name),
       existing -> processUpdate(repositoryDto, existing),
@@ -204,7 +204,8 @@ public class RepositoryResource {
   }
 
   private Supplier<Repository> loadBy(String namespace, String name) {
-    return () -> Optional.ofNullable(manager.get(new NamespaceAndName(namespace, name))).orElseThrow(() -> new NotFoundException(Repository.class, namespace + "/" + name));
+    NamespaceAndName namespaceAndName = new NamespaceAndName(namespace, name);
+    return () -> Optional.ofNullable(manager.get(namespaceAndName)).orElseThrow(() -> NotFoundException.notFound(namespaceAndName).build());
   }
 
   private Predicate<Repository> nameAndNamespaceStaysTheSame(String namespace, String name) {

scm-webapp/src/main/java/sonia/scm/api/v2/resources/SingleResourceManagerAdapter.java

@@ -33,6 +33,7 @@ class SingleResourceManagerAdapter<MODEL_OBJECT extends ModelObject,
                              DTO extends HalRepresentation> extends AbstractManagerResource<MODEL_OBJECT> {
 
   private final Function<Throwable, Optional<Response>> errorHandler;
+  private final Class<MODEL_OBJECT> type;
 
   SingleResourceManagerAdapter(Manager<MODEL_OBJECT> manager, Class<MODEL_OBJECT> type) {
     this(manager, type, e -> Optional.empty());
@@ -44,6 +45,7 @@ class SingleResourceManagerAdapter<MODEL_OBJECT extends ModelObject,
     Function<Throwable, Optional<Response>> errorHandler) {
     super(manager, type);
     this.errorHandler = errorHandler;
+    this.type = type;
   }
 
   /**
@@ -58,14 +60,14 @@ class SingleResourceManagerAdapter<MODEL_OBJECT extends ModelObject,
    * Update the model object for the given id according to the given function and returns a corresponding http response.
    * This handles all corner cases, eg. no matching object for the id or missing privileges.
    */
-  Response update(Supplier<MODEL_OBJECT> reader, Function<MODEL_OBJECT, MODEL_OBJECT> applyChanges, Predicate<MODEL_OBJECT> hasSameKey) throws ConcurrentModificationException {
+  Response update(Supplier<MODEL_OBJECT> reader, Function<MODEL_OBJECT, MODEL_OBJECT> applyChanges, Predicate<MODEL_OBJECT> hasSameKey) {
     MODEL_OBJECT existingModelObject = reader.get();
     MODEL_OBJECT changedModelObject = applyChanges.apply(existingModelObject);
     if (!hasSameKey.test(changedModelObject)) {
       return Response.status(BAD_REQUEST).entity("illegal change of id").build();
     }
     else if (modelObjectWasModifiedConcurrently(existingModelObject, changedModelObject)) {
-      throw new ConcurrentModificationException();
+      throw new ConcurrentModificationException(type, existingModelObject.getId());
     }
     return update(getId(existingModelObject), changedModelObject);
   }

scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserResource.java

@@ -101,7 +101,7 @@ public class UserResource {
     @ResponseCode(code = 500, condition = "internal server error")
   })
   @TypeHint(TypeHint.NO_CONTENT.class)
-  public Response update(@PathParam("id") String name, @Valid UserDto userDto) throws ConcurrentModificationException {
+  public Response update(@PathParam("id") String name, @Valid UserDto userDto) {
     return adapter.update(name, existing -> dtoToUserMapper.map(userDto, existing.getPassword()));
   }