Check preconditions when setting parent project through REST

Only update the parent project if the new parent project exists and if
setting this parent doesn't introduce a cycle in the line of projects.
Never set a parent project for the All-Projects root project.

Change-Id: I9caec6921d46f8205febdacb31f52bd6c21f28c8
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/rest/project/SetParentIT.java

@@ -24,6 +24,8 @@ import com.google.gerrit.acceptance.RestResponse;
 import com.google.gerrit.acceptance.RestSession;
 import com.google.gerrit.acceptance.SshSession;
 import com.google.gerrit.acceptance.TestAccount;
+import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.server.config.AllProjectsNameProvider;
 import com.google.gson.Gson;
 import com.google.gson.reflect.TypeToken;
 import com.google.inject.Inject;
@@ -42,6 +44,9 @@ public class SetParentIT extends AbstractDaemonTest {
   @Inject
   private AccountCreator accounts;
 
+  @Inject
+  private AllProjectsNameProvider allProjects;
+
   private RestSession adminSession;
   private RestSession userSession;
   private SshSession sshSession;
@@ -98,6 +103,47 @@ public class SetParentIT extends AbstractDaemonTest {
     r.consume();
   }
 
+  @Test
+  public void setParentForAllProjects_Conflict() throws IOException {
+    RestResponse r =
+        adminSession.put("/projects/" + allProjects.get() + "/parent",
+            new ParentInput(project));
+    assertEquals(HttpStatus.SC_CONFLICT, r.getStatusCode());
+    r.consume();
+  }
+
+  @Test
+  public void setInvalidParent_Conflict() throws IOException, JSchException {
+    RestResponse r =
+        adminSession.put("/projects/" + project + "/parent",
+            new ParentInput(project));
+    assertEquals(HttpStatus.SC_CONFLICT, r.getStatusCode());
+    r.consume();
+
+    String child = "child";
+    createProject(sshSession, child, new Project.NameKey(project), true);
+    r = adminSession.put("/projects/" + project + "/parent",
+           new ParentInput(child));
+    assertEquals(HttpStatus.SC_CONFLICT, r.getStatusCode());
+    r.consume();
+
+    String grandchild = "grandchild";
+    createProject(sshSession, grandchild, new Project.NameKey(child), true);
+    r = adminSession.put("/projects/" + project + "/parent",
+           new ParentInput(grandchild));
+    assertEquals(HttpStatus.SC_CONFLICT, r.getStatusCode());
+    r.consume();
+  }
+
+  @Test
+  public void setNonExistingParent_UnprocessibleEntity() throws IOException {
+    RestResponse r =
+        adminSession.put("/projects/" + project + "/parent",
+            new ParentInput("non-existing"));
+    assertEquals(HttpStatus.SC_UNPROCESSABLE_ENTITY, r.getStatusCode());
+    r.consume();
+  }
+
   @SuppressWarnings("unused")
   private static class ParentInput {
     String parent;

gerrit-server/src/main/java/com/google/gerrit/server/project/SetParent.java

@@ -15,13 +15,16 @@
 package com.google.gerrit.server.project;
 
 import com.google.common.base.Objects;
+import com.google.common.base.Predicate;
 import com.google.common.base.Strings;
+import com.google.common.collect.Iterables;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.DefaultInput;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestModifyView;
+import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.config.AllProjectsName;
@@ -33,6 +36,8 @@ import com.google.inject.Inject;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.errors.RepositoryNotFoundException;
 
+import java.io.IOException;
+
 class SetParent implements RestModifyView<ProjectResource, Input> {
   static class Input {
     @DefaultInput
@@ -54,21 +59,45 @@ class SetParent implements RestModifyView<ProjectResource, Input> {
   }
 
   @Override
-  public String apply(ProjectResource resource, Input input)
+  public String apply(final ProjectResource rsrc, Input input) throws AuthException,
-      throws AuthException, BadRequestException, ResourceConflictException,
+      BadRequestException, ResourceConflictException,
-      Exception {
+      ResourceNotFoundException, UnprocessableEntityException, IOException {
-    ProjectControl ctl = resource.getControl();
+    ProjectControl ctl = rsrc.getControl();
     IdentifiedUser user = (IdentifiedUser) ctl.getCurrentUser();
     if (!user.getCapabilities().canAdministrateServer()) {
       throw new AuthException("not administrator");
     }
 
+    if (rsrc.getNameKey().equals(allProjects)) {
+      throw new ResourceConflictException("cannot set parent of "
+          + allProjects.get());
+    }
+
+    input.parent = Strings.emptyToNull(input.parent);
+    if (input.parent != null) {
+      ProjectState parent = cache.get(new Project.NameKey(input.parent));
+      if (parent == null) {
+        throw new UnprocessableEntityException("parent project " + input.parent
+            + " not found");
+      }
+
+      if (Iterables.tryFind(parent.tree(), new Predicate<ProjectState>() {
+        @Override
+        public boolean apply(ProjectState input) {
+          return input.getProject().getNameKey().equals(rsrc.getNameKey());
+        }
+      }).isPresent()) {
+        throw new ResourceConflictException("cycle exists between "
+            + rsrc.getName() + " and " + parent.getProject().getName());
+      }
+    }
+
     try {
-      MetaDataUpdate md = updateFactory.create(resource.getNameKey());
+      MetaDataUpdate md = updateFactory.create(rsrc.getNameKey());
       try {
         ProjectConfig config = ProjectConfig.read(md);
         Project project = config.getProject();
-        project.setParentName(Strings.emptyToNull(input.parent));
+        project.setParentName(input.parent);
 
         String msg = Strings.emptyToNull(input.commitMessage);
         if (msg == null) {
@@ -89,7 +118,7 @@ class SetParent implements RestModifyView<ProjectResource, Input> {
         md.close();
       }
     } catch (RepositoryNotFoundException notFound) {
-      throw new ResourceNotFoundException(resource.getName());
+      throw new ResourceNotFoundException(rsrc.getName());
     } catch (ConfigInvalidException e) {
       throw new ResourceConflictException(String.format(
           "invalid project.config: %s", e.getMessage()));