Merge changes from topic "project-cache-get-optional"

* changes:
  Remove ProjectCache#strictGet(NameKey, boolean)
  Make ProjectCache#get return an Optional<ProjectState>

java/com/google/gerrit/elasticsearch/ElasticProjectIndex.java

@@ -32,12 +32,14 @@ import com.google.gerrit.index.query.QueryParseException;
 import com.google.gerrit.server.config.SitePaths;
 import com.google.gerrit.server.index.IndexUtils;
 import com.google.gerrit.server.project.ProjectCache;
+import com.google.gerrit.server.project.ProjectState;
 import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import com.google.inject.assistedinject.Assisted;
+import java.util.Optional;
 import java.util.Set;
 import org.apache.http.HttpStatus;
 import org.elasticsearch.client.Response;
@@ -119,6 +121,10 @@ public class ElasticProjectIndex extends AbstractElasticIndex<Project.NameKey, P
 
     Project.NameKey nameKey =
         Project.nameKey(source.getAsJsonObject().get(ProjectField.NAME.getName()).getAsString());
-    return projectCache.get().get(nameKey).toProjectData();
+    Optional<ProjectState> state = projectCache.get().get(nameKey);
+    if (!state.isPresent()) {
+      return null;
+    }
+    return state.get().toProjectData();
   }
 }

java/com/google/gerrit/gpg/SignedPushModule.java

@@ -14,6 +14,8 @@
 
 package com.google.gerrit.gpg;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
+
 import com.google.common.base.Strings;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.entities.BooleanProjectConfig;
@@ -87,7 +89,7 @@ class SignedPushModule extends AbstractModule {
 
     @Override
     public void init(Project.NameKey project, ReceivePack rp) {
-      ProjectState ps = projectCache.get(project);
+      ProjectState ps = projectCache.get(project).orElseThrow(illegalState(project));
       if (!ps.is(BooleanProjectConfig.ENABLE_SIGNED_PUSH)) {
         rp.setSignedPushConfig(null);
         return;

java/com/google/gerrit/lucene/LuceneProjectIndex.java

@@ -142,7 +142,6 @@ public class LuceneProjectIndex extends AbstractLuceneIndex<Project.NameKey, Pro
   @Override
   protected ProjectData fromDocument(Document doc) {
     Project.NameKey nameKey = Project.nameKey(doc.getField(NAME.getName()).stringValue());
-    ProjectState projectState = projectCache.get().get(nameKey);
+    return projectCache.get().get(nameKey).map(ProjectState::toProjectData).orElse(null);
-    return projectState == null ? null : projectState.toProjectData();
   }
 }

java/com/google/gerrit/server/change/RevisionJson.java

@@ -27,6 +27,7 @@ import static com.google.gerrit.extensions.client.ListChangesOption.DOWNLOAD_COM
 import static com.google.gerrit.extensions.client.ListChangesOption.PUSH_CERTIFICATES;
 import static com.google.gerrit.extensions.client.ListChangesOption.WEB_LINKS;
 import static com.google.gerrit.server.CommonConverters.toGitPerson;
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
@@ -306,7 +307,7 @@ public class RevisionJson {
         }
         out.commitWithFooters =
             mergeUtilFactory
-                .create(projectCache.get(project))
+                .create(projectCache.get(project).orElseThrow(illegalState(project)))
                 .createCommitMessageOnSubmit(commit, mergeTip, cd.notes(), in.id());
       }
     }

java/com/google/gerrit/server/config/PluginConfigFactory.java

@@ -14,6 +14,8 @@
 
 package com.google.gerrit.server.config;
 
+import static com.google.gerrit.server.project.ProjectCache.noSuchProject;
+
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.server.plugins.Plugin;
@@ -129,10 +131,8 @@ public class PluginConfigFactory implements ReloadPluginListener {
    */
   public PluginConfig getFromProjectConfig(Project.NameKey projectName, String pluginName)
       throws NoSuchProjectException {
-    ProjectState projectState = projectCache.get(projectName);
+    ProjectState projectState =
-    if (projectState == null) {
+        projectCache.get(projectName).orElseThrow(noSuchProject(projectName));
-      throw new NoSuchProjectException(projectName);
-    }
     return getFromProjectConfig(projectState, pluginName);
   }
 
@@ -363,10 +363,8 @@ public class PluginConfigFactory implements ReloadPluginListener {
 
   private ProjectLevelConfig getPluginConfig(Project.NameKey projectName, String pluginName)
       throws NoSuchProjectException {
-    ProjectState projectState = projectCache.get(projectName);
+    ProjectState projectState =
-    if (projectState == null) {
+        projectCache.get(projectName).orElseThrow(noSuchProject(projectName));
-      throw new NoSuchProjectException(projectName);
-    }
     return projectState.getConfig(pluginName + EXTENSION);
   }
 

java/com/google/gerrit/server/events/EventBroker.java

@@ -37,6 +37,7 @@ import com.google.gerrit.server.project.ProjectState;
 import com.google.gson.Gson;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
+import java.util.Optional;
 
 /** Distributes Events to listeners if they are allowed to see them */
 @Singleton
@@ -146,8 +147,8 @@ public class EventBroker implements EventDispatcher {
 
   protected boolean isVisibleTo(Project.NameKey project, CurrentUser user) {
     try {
-      ProjectState state = projectCache.get(project);
+      Optional<ProjectState> state = projectCache.get(project);
-      if (state == null || !state.statePermitsRead()) {
+      if (!state.isPresent() || !state.get().statePermitsRead()) {
         return false;
       }
 
@@ -162,8 +163,8 @@ public class EventBroker implements EventDispatcher {
     if (change == null) {
       return false;
     }
-    ProjectState pe = projectCache.get(change.getProject());
+    Optional<ProjectState> pe = projectCache.get(change.getProject());
-    if (pe == null || !pe.statePermitsRead()) {
+    if (!pe.isPresent() || !pe.get().statePermitsRead()) {
       return false;
     }
     try {
@@ -179,8 +180,8 @@ public class EventBroker implements EventDispatcher {
 
   protected boolean isVisibleTo(BranchNameKey branchName, CurrentUser user)
       throws PermissionBackendException {
-    ProjectState pe = projectCache.get(branchName.project());
+    Optional<ProjectState> pe = projectCache.get(branchName.project());
-    if (pe == null || !pe.statePermitsRead()) {
+    if (!pe.isPresent() || !pe.get().statePermitsRead()) {
       return false;
     }
 

java/com/google/gerrit/server/events/StreamEventsApiListener.java

@@ -14,6 +14,8 @@
 
 package com.google.gerrit.server.events;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
+
 import com.google.common.base.Supplier;
 import com.google.common.base.Suppliers;
 import com.google.common.collect.Sets;
@@ -24,6 +26,7 @@ import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.BranchNameKey;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.PatchSet;
+import com.google.gerrit.entities.Project;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.extensions.common.AccountInfo;
 import com.google.gerrit.extensions.common.ApprovalInfo;
@@ -215,7 +218,9 @@ public class StreamEventsApiListener
     final Map<String, Short> approvals = convertApprovalsMap(newApprovals);
     return Suppliers.memoize(
         () -> {
-          LabelTypes labelTypes = projectCache.get(change.getProject()).getLabelTypes();
+          Project.NameKey nameKey = change.getProject();
+          LabelTypes labelTypes =
+              projectCache.get(nameKey).orElseThrow(illegalState(nameKey)).getLabelTypes();
           if (approvals.size() > 0) {
             ApprovalAttribute[] r = new ApprovalAttribute[approvals.size()];
             int i = 0;

java/com/google/gerrit/server/git/receive/ReceiveCommits.java

@@ -30,6 +30,7 @@ import static com.google.gerrit.server.git.receive.ReceiveConstants.PUSH_OPTION_
 import static com.google.gerrit.server.git.receive.ReceiveConstants.SAME_CHANGE_ID_IN_MULTIPLE_CHANGES;
 import static com.google.gerrit.server.git.validators.CommitValidators.NEW_PATCHSET_PATTERN;
 import static com.google.gerrit.server.mail.MailUtil.getRecipientsFromFooters;
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.util.Objects.requireNonNull;
 import static java.util.stream.Collectors.joining;
@@ -1204,7 +1205,7 @@ class ReceiveCommits {
                 }
               }
 
-              if (projectCache.get(newParent) == null) {
+              if (!projectCache.get(newParent).isPresent()) {
                 reject(cmd, "invalid project configuration: parent does not exist");
                 return;
               }
@@ -1810,7 +1811,10 @@ class ReceiveCommits {
       }
 
       boolean privateByDefault =
-          projectCache.get(project.getNameKey()).is(BooleanProjectConfig.PRIVATE_BY_DEFAULT);
+          projectCache
+              .get(project.getNameKey())
+              .orElseThrow(illegalState(project.getNameKey()))
+              .is(BooleanProjectConfig.PRIVATE_BY_DEFAULT);
       setChangeAsPrivate =
           magicBranch.isPrivate || (privateByDefault && !magicBranch.removePrivate);
 
@@ -2088,6 +2092,7 @@ class ReceiveCommits {
             start.getParentCount() == 1
                 && projectCache
                     .get(project.getNameKey())
+                    .orElseThrow(illegalState(project.getNameKey()))
                     .is(BooleanProjectConfig.REJECT_IMPLICIT_MERGES)
                 // Don't worry about implicit merges when creating changes for
                 // already-merged commits; they're already in history, so it's too
@@ -3091,7 +3096,8 @@ class ReceiveCommits {
           logger.atWarning().withCause(e).log(
               "Cannot evict from project cache, name key: %s", project.getName());
         }
-        ProjectState ps = projectCache.get(project.getNameKey());
+        ProjectState ps =
+            projectCache.get(project.getNameKey()).orElseThrow(illegalState(project.getNameKey()));
         try {
           logger.atFine().log("Updating project description");
           repo.setGitwebDescription(ps.getProject().getDescription());

java/com/google/gerrit/server/git/validators/MergeValidators.java

@@ -216,7 +216,7 @@ public class MergeValidators {
                     String.format(
                         " %s must inherit from %s", allUsersName.get(), allProjectsName.get()));
               }
-              if (projectCache.get(newParent) == null) {
+              if (!projectCache.get(newParent).isPresent()) {
                 throw new MergeValidationException(PARENT_NOT_FOUND);
               }
             }

java/com/google/gerrit/server/group/db/RenameGroupOp.java

@@ -14,6 +14,8 @@
 
 package com.google.gerrit.server.group.db;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
+
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.data.GroupReference;
 import com.google.gerrit.entities.AccountGroup;
@@ -85,7 +87,8 @@ class RenameGroupOp extends DefaultQueueOp {
   public void run() {
     Iterable<Project.NameKey> names = tryingAgain ? retryOn : projectCache.all();
     for (Project.NameKey projectName : names) {
-      ProjectConfig config = projectCache.get(projectName).getConfig();
+      ProjectConfig config =
+          projectCache.get(projectName).orElseThrow(illegalState(projectName)).getConfig();
       GroupReference ref = config.getGroup(uuid);
       if (ref == null || newName.equals(ref.getName())) {
         continue;

java/com/google/gerrit/server/index/project/AllProjectsIndexer.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.server.index.project;
 
 import static com.google.gerrit.server.git.QueueProvider.QueueType.BATCH;
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 
 import com.google.common.base.Stopwatch;
 import com.google.common.flogger.FluentLogger;
@@ -78,7 +79,8 @@ public class AllProjectsIndexer extends SiteIndexer<Project.NameKey, ProjectData
               () -> {
                 try {
                   projectCache.evict(name);
-                  index.replace(projectCache.get(name).toProjectData());
+                  index.replace(
+                      projectCache.get(name).orElseThrow(illegalState(name)).toProjectData());
                   verboseWriter.println("Reindexed " + desc);
                   done.incrementAndGet();
                 } catch (Exception e) {

java/com/google/gerrit/server/index/project/ProjectIndexerImpl.java

@@ -34,6 +34,7 @@ import com.google.inject.assistedinject.Assisted;
 import com.google.inject.assistedinject.AssistedInject;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Optional;
 
 /**
  * Implementation for indexing a Gerrit-managed repository (project). The project will be loaded
@@ -77,10 +78,10 @@ public class ProjectIndexerImpl implements ProjectIndexer {
 
   @Override
   public void index(Project.NameKey nameKey) {
-    ProjectState projectState = projectCache.get(nameKey);
+    Optional<ProjectState> projectState = projectCache.get(nameKey);
-    if (projectState != null) {
+    if (projectState.isPresent()) {
       logger.atFine().log("Replace project %s in index", nameKey.get());
-      ProjectData projectData = projectState.toProjectData();
+      ProjectData projectData = projectState.get().toProjectData();
       for (ProjectIndex i : getWriteIndexes()) {
         try (TraceTimer traceTimer =
             TraceContext.newTimer(

java/com/google/gerrit/server/index/project/StalenessChecker.java

@@ -14,6 +14,8 @@
 
 package com.google.gerrit.server.index.project;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
+
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.MultimapBuilder;
 import com.google.common.collect.SetMultimap;
@@ -57,7 +59,8 @@ public class StalenessChecker {
    * provided {@link com.google.gerrit.entities.Project.NameKey}.
    */
   public StalenessCheckResult check(Project.NameKey project) {
-    ProjectData projectData = projectCache.get(project).toProjectData();
+    ProjectData projectData =
+        projectCache.get(project).orElseThrow(illegalState(project)).toProjectData();
     ProjectIndex i = indexes.getSearchIndex();
     if (i == null) {
       return StalenessCheckResult

java/com/google/gerrit/server/mail/send/ChangeEmail.java

@@ -142,7 +142,7 @@ public abstract class ChangeEmail extends NotificationEmail {
   @Override
   protected void init() throws EmailException {
     if (args.projectCache != null) {
-      projectState = args.projectCache.get(change.getProject());
+      projectState = args.projectCache.get(change.getProject()).orElse(null);
     } else {
       projectState = null;
     }

java/com/google/gerrit/server/notedb/ChangeUpdate.java

@@ -41,6 +41,7 @@ import static com.google.gerrit.server.notedb.ChangeNoteUtil.FOOTER_TAG;
 import static com.google.gerrit.server.notedb.ChangeNoteUtil.FOOTER_TOPIC;
 import static com.google.gerrit.server.notedb.ChangeNoteUtil.FOOTER_WORK_IN_PROGRESS;
 import static com.google.gerrit.server.notedb.NoteDbUtil.sanitizeFooter;
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.util.Comparator.naturalOrder;
 import static java.util.Objects.requireNonNull;
 import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
@@ -169,7 +170,11 @@ public class ChangeUpdate extends AbstractChangeUpdate {
         notes,
         user,
         when,
-        projectCache.get(notes.getProjectName()).getLabelTypes().nameComparator(),
+        projectCache
+            .get(notes.getProjectName())
+            .orElseThrow(illegalState(notes.getProjectName()))
+            .getLabelTypes()
+            .nameComparator(),
         noteUtil);
   }
 

java/com/google/gerrit/server/project/ChildProjects.java

@@ -65,7 +65,16 @@ public class ChildProjects {
   private Map<Project.NameKey, Project> readAllReadableProjects() {
     Map<Project.NameKey, Project> projects = new HashMap<>();
     for (Project.NameKey name : projectCache.all()) {
-      ProjectState c = projectCache.get(name);
+
+      ProjectState c =
+          projectCache
+              .get(name)
+              .orElseThrow(
+                  () ->
+                      new IllegalStateException(
+                          "race while traversing projects. got "
+                              + name
+                              + " when loading all projects, but can't load it now"));
       if (c != null && c.statePermitsRead()) {
         projects.put(c.getNameKey(), c.getProject());
       }

java/com/google/gerrit/server/project/ProjectCache.java

@@ -20,10 +20,28 @@ import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.exceptions.StorageException;
 import java.io.IOException;
+import java.util.Optional;
 import java.util.Set;
+import java.util.function.Supplier;
 
 /** Cache of project information, including access rights. */
 public interface ProjectCache {
+  /**
+   * Returns a supplier to be used as a short-hand when unwrapping an {@link Optional} returned from
+   * this cache.
+   */
+  static Supplier<IllegalStateException> illegalState(Project.NameKey nameKey) {
+    return () -> new IllegalStateException("unable to find project " + nameKey);
+  }
+
+  /**
+   * Returns a supplier to be used as a short-hand when unwrapping an {@link Optional} returned from
+   * this cache.
+   */
+  static Supplier<NoSuchProjectException> noSuchProject(Project.NameKey nameKey) {
+    return () -> new NoSuchProjectException(nameKey);
+  }
+
   /** @return the parent state for all projects on this server. */
   ProjectState getAllProjects();
 
@@ -34,11 +52,12 @@ public interface ProjectCache {
    * Get the cached data for a project by its unique name.
    *
    * @param projectName name of the project.
-   * @return the cached data; null if no such project exists or the projectName is null
+   * @return an {@link Optional} wrapping the the cached data; {@code absent} if no such project
+   *     exists or the projectName is null
    * @throws StorageException when there was an error.
    * @see #checkedGet(com.google.gerrit.entities.Project.NameKey)
    */
-  ProjectState get(@Nullable Project.NameKey projectName) throws StorageException;
+  Optional<ProjectState> get(@Nullable Project.NameKey projectName) throws StorageException;
 
   /**
    * Get the cached data for a project by its unique name.
@@ -51,19 +70,6 @@ public interface ProjectCache {
   @Deprecated
   ProjectState checkedGet(@Nullable Project.NameKey projectName) throws IOException;
 
-  /**
-   * Get the cached data for a project by its unique name.
-   *
-   * @param projectName name of the project.
-   * @param strict true when any error generates an exception
-   * @throws Exception in case of any error (strict = true) or only for I/O or other internal
-   *     errors.
-   * @return the cached data or null when strict = false
-   * @deprecated use {@link #get(Project.NameKey)} instead.
-   */
-  @Deprecated
-  ProjectState checkedGet(Project.NameKey projectName, boolean strict) throws Exception;
-
   /**
    * Invalidate the cached information about the given project, and triggers reindexing for it
    *

java/com/google/gerrit/server/project/ProjectCacheImpl.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.project;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.util.stream.Collectors.toSet;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -48,6 +49,7 @@ import com.google.inject.TypeLiteral;
 import com.google.inject.name.Named;
 import java.io.IOException;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.locks.Lock;
@@ -125,29 +127,18 @@ public class ProjectCacheImpl implements ProjectCache {
 
   @Override
   public ProjectState getAllProjects() {
-    ProjectState state = get(allProjectsName);
+    return get(allProjectsName).orElseThrow(illegalState(allProjectsName));
-    if (state == null) {
-      // This should never occur, the server must have this
-      // project to process anything.
-      throw new IllegalStateException("Missing project " + allProjectsName);
-    }
-    return state;
   }
 
   @Override
   public ProjectState getAllUsers() {
-    ProjectState state = get(allUsersName);
+    return get(allUsersName).orElseThrow(illegalState(allUsersName));
-    if (state == null) {
-      // This should never occur.
-      throw new IllegalStateException("Missing project " + allUsersName);
-    }
-    return state;
   }
 
   @Override
-  public ProjectState get(Project.NameKey projectName) {
+  public Optional<ProjectState> get(Project.NameKey projectName) {
     try {
-      return checkedGet(projectName);
+      return Optional.ofNullable(checkedGet(projectName));
     } catch (IOException e) {
       throw new StorageException("project state not available", e);
     }
@@ -173,11 +164,6 @@ public class ProjectCacheImpl implements ProjectCache {
     }
   }
 
-  @Override
-  public ProjectState checkedGet(Project.NameKey projectName, boolean strict) throws Exception {
-    return strict ? strictCheckedGet(projectName) : checkedGet(projectName);
-  }
-
   private ProjectState strictCheckedGet(Project.NameKey projectName) throws Exception {
     ProjectState state = byName.get(projectName.get());
     if (state != null && state.needsRefresh(clock.read())) {

java/com/google/gerrit/server/project/ProjectCacheWarmer.java

@@ -53,7 +53,16 @@ public class ProjectCacheWarmer implements LifecycleListener {
           new Thread(
               () -> {
                 for (Project.NameKey name : cache.all()) {
-                  pool.execute(() -> cache.get(name));
+                  pool.execute(
+                      () ->
+                          cache
+                              .get(name)
+                              .orElseThrow(
+                                  () ->
+                                      new IllegalStateException(
+                                          "race while traversing projects. got "
+                                              + name
+                                              + " when loading all projects, but can't load it now")));
                 }
                 pool.shutdown();
                 try {

java/com/google/gerrit/server/project/ProjectCreator.java

@@ -14,6 +14,8 @@
 
 package com.google.gerrit.server.project;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
+
 import com.google.common.base.MoreObjects;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.data.AccessSection;
@@ -124,7 +126,7 @@ public class ProjectCreator {
 
         fire(nameKey, head);
 
-        return projectCache.get(nameKey);
+        return projectCache.get(nameKey).orElseThrow(illegalState(nameKey));
       }
     } catch (RepositoryCaseMismatchException e) {
       throw new ResourceConflictException(

java/com/google/gerrit/server/project/ProjectHierarchyIterator.java

@@ -23,6 +23,7 @@ import com.google.gerrit.server.config.AllProjectsName;
 import java.util.Iterator;
 import java.util.List;
 import java.util.NoSuchElementException;
+import java.util.Optional;
 import java.util.Set;
 
 /**
@@ -65,16 +66,16 @@ class ProjectHierarchyIterator implements Iterator<ProjectState> {
   private ProjectState computeNext(ProjectState n) {
     Project.NameKey parentName = n.getProject().getParent();
     if (parentName != null && visit(parentName)) {
-      ProjectState p = cache.get(parentName);
+      Optional<ProjectState> p = cache.get(parentName);
-      if (p != null) {
+      if (p.isPresent()) {
-        return p;
+        return p.get();
       }
     }
 
     // Parent does not exist or was already visited.
     // Fall back to visit All-Projects exactly once.
     if (seen.add(allProjectsName)) {
-      return cache.get(allProjectsName);
+      return cache.getAllProjects();
     }
     return null;
   }

java/com/google/gerrit/server/project/SubmitRuleEvaluator.java

@@ -14,6 +14,8 @@
 
 package com.google.gerrit.server.project;
 
+import static com.google.gerrit.server.project.ProjectCache.noSuchProject;
+
 import com.google.common.collect.Streams;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.data.SubmitRecord;
@@ -108,17 +110,13 @@ public class SubmitRuleEvaluator {
   public List<SubmitRecord> evaluate(ChangeData cd) {
     try (Timer0.Context ignored = submitRuleEvaluationLatency.start()) {
       Change change;
-      ProjectState projectState;
       try {
         change = cd.change();
         if (change == null) {
           throw new StorageException("Change not found");
         }
 
-        projectState = projectCache.get(cd.project());
+        projectCache.get(cd.project()).orElseThrow(noSuchProject(cd.project()));
-        if (projectState == null) {
-          throw new NoSuchProjectException(cd.project());
-        }
       } catch (StorageException | NoSuchProjectException e) {
         return Collections.singletonList(ruleError("Error looking up change " + cd.getId(), e));
       }
@@ -154,10 +152,7 @@ public class SubmitRuleEvaluator {
     try (Timer0.Context ignored = submitTypeEvaluationLatency.start()) {
       ProjectState projectState;
       try {
-        projectState = projectCache.get(cd.project());
+        projectState = projectCache.get(cd.project()).orElseThrow(noSuchProject(cd.project()));
-        if (projectState == null) {
-          throw new NoSuchProjectException(cd.project());
-        }
       } catch (NoSuchProjectException e) {
         return typeError("Error looking up change " + cd.getId(), e);
       }

java/com/google/gerrit/server/project/SuggestParentCandidates.java

@@ -25,6 +25,7 @@ import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 
 @Singleton
@@ -51,9 +52,9 @@ public class SuggestParentCandidates {
   private Set<Project.NameKey> readableParents() {
     Set<Project.NameKey> parents = new HashSet<>();
     for (Project.NameKey p : projectCache.all()) {
-      ProjectState ps = projectCache.get(p);
+      Optional<ProjectState> ps = projectCache.get(p);
-      if (ps != null && ps.statePermitsRead()) {
+      if (ps.isPresent() && ps.get().statePermitsRead()) {
-        Project.NameKey parent = ps.getProject().getParent();
+        Project.NameKey parent = ps.get().getProject().getParent();
         if (parent != null) {
           parents.add(parent);
         }

java/com/google/gerrit/server/query/change/ChangeData.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.query.change;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.util.Objects.requireNonNull;
 import static java.util.stream.Collectors.toList;
 import static java.util.stream.Collectors.toMap;
@@ -915,7 +916,9 @@ public class ChangeData {
             return false;
           }
           String mergeStrategy =
-              mergeUtilFactory.create(projectCache.get(project())).mergeStrategyName();
+              mergeUtilFactory
+                  .create(projectCache.get(project()).orElseThrow(illegalState(project())))
+                  .mergeStrategyName();
           mergeable =
               mergeabilityCache.get(ps.commitId(), ref, str.type, mergeStrategy, c.getDest(), repo);
         } catch (IOException e) {

java/com/google/gerrit/server/query/change/ConflictsPredicate.java

@@ -16,6 +16,7 @@ package com.google.gerrit.server.query.change;
 
 import static com.google.common.base.MoreObjects.firstNonNull;
 import static com.google.common.flogger.LazyArgs.lazy;
+import static com.google.gerrit.server.project.ProjectCache.noSuchProject;
 import static java.util.concurrent.TimeUnit.MINUTES;
 
 import com.google.common.flogger.FluentLogger;
@@ -218,10 +219,7 @@ public class ConflictsPredicate {
 
     ProjectState getProjectState() throws NoSuchProjectException {
       if (projectState == null) {
-        projectState = projectCache.get(cd.project());
+        projectState = projectCache.get(cd.project()).orElseThrow(noSuchProject(cd.project()));
-        if (projectState == null) {
-          throw new NoSuchProjectException(cd.project());
-        }
       }
       return projectState;
     }

java/com/google/gerrit/server/query/change/EqualsLabelPredicate.java

@@ -29,6 +29,7 @@ import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.project.ProjectState;
 import java.io.IOException;
+import java.util.Optional;
 
 public class EqualsLabelPredicate extends ChangeIndexPredicate {
   protected final ProjectCache projectCache;
@@ -60,14 +61,14 @@ public class EqualsLabelPredicate extends ChangeIndexPredicate {
       return false;
     }
 
-    ProjectState project = projectCache.get(c.getDest().project());
+    Optional<ProjectState> project = projectCache.get(c.getDest().project());
-    if (project == null) {
+    if (!project.isPresent()) {
       // The project has disappeared.
       //
       return false;
     }
 
-    LabelType labelType = type(project.getLabelTypes(), label);
+    LabelType labelType = type(project.get().getLabelTypes(), label);
     if (labelType == null) {
       return false; // Label is not defined by this project.
     }

java/com/google/gerrit/server/query/change/ParentProjectPredicate.java

@@ -26,6 +26,7 @@ import com.google.gerrit.server.project.ProjectState;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 
 public class ParentProjectPredicate extends OrPredicate<ChangeData> {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
@@ -40,15 +41,15 @@ public class ParentProjectPredicate extends OrPredicate<ChangeData> {
 
   protected static List<Predicate<ChangeData>> predicates(
       ProjectCache projectCache, ChildProjects childProjects, String value) {
-    ProjectState projectState = projectCache.get(Project.nameKey(value));
+    Optional<ProjectState> projectState = projectCache.get(Project.nameKey(value));
-    if (projectState == null) {
+    if (!projectState.isPresent()) {
       return Collections.emptyList();
     }
 
     List<Predicate<ChangeData>> r = new ArrayList<>();
-    r.add(new ProjectPredicate(projectState.getName()));
+    r.add(new ProjectPredicate(projectState.get().getName()));
     try {
-      for (ProjectInfo p : childProjects.list(projectState.getNameKey())) {
+      for (ProjectInfo p : childProjects.list(projectState.get().getNameKey())) {
         r.add(new ProjectPredicate(p.name));
       }
     } catch (PermissionBackendException e) {

java/com/google/gerrit/server/restapi/change/GetDiff.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.restapi.change;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static com.google.gerrit.util.cli.Localizable.localizable;
 
 import com.google.common.base.MoreObjects;
@@ -146,7 +147,7 @@ public class GetDiff implements RestReadView<FileResource> {
       psf.setLoadComments(context != DiffPreferencesInfo.WHOLE_FILE_CONTEXT);
       PatchScript ps = psf.call();
       Project.NameKey projectName = resource.getRevision().getChange().getProject();
-      ProjectState state = projectCache.get(projectName);
+      ProjectState state = projectCache.get(projectName).orElseThrow(illegalState(projectName));
       DiffSide sideA =
           DiffSide.create(
               ps.getFileInfoA(),

java/com/google/gerrit/server/restapi/change/GetFixPreview.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.restapi.change;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.util.stream.Collectors.groupingBy;
 
 import com.google.common.base.MoreObjects;
@@ -78,7 +79,8 @@ public class GetFixPreview implements RestReadView<FixResource> {
     PatchSet patchSet = resource.getRevisionResource().getPatchSet();
     ChangeNotes notes = resource.getRevisionResource().getNotes();
     Change change = notes.getChange();
-    ProjectState state = projectCache.get(change.getProject());
+    ProjectState state =
+        projectCache.get(change.getProject()).orElseThrow(illegalState(change.getProject()));
     Map<String, List<FixReplacement>> fixReplacementsPerFilePath =
         resource.getFixReplacements().stream()
             .collect(groupingBy(fixReplacement -> fixReplacement.path));

java/com/google/gerrit/server/restapi/change/Mergeable.java

@@ -14,6 +14,8 @@
 
 package com.google.gerrit.server.restapi.change;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
+
 import com.google.gerrit.common.data.SubmitTypeRecord;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.PatchSet;
@@ -105,7 +107,8 @@ public class Mergeable implements RestReadView<RevisionResource> {
     try (Repository git = gitManager.openRepository(change.getProject())) {
       ObjectId commit = ps.commitId();
       Ref ref = git.getRefDatabase().exactRef(change.getDest().branch());
-      ProjectState projectState = projectCache.get(change.getProject());
+      ProjectState projectState =
+          projectCache.get(change.getProject()).orElseThrow(illegalState(change.getProject()));
       String strategy = mergeUtilFactory.create(projectState).mergeStrategyName();
       result.strategy = strategy;
       result.mergeable = isMergable(git, change, commit, ref, result.submitType, strategy);

java/com/google/gerrit/server/restapi/change/TestSubmitRule.java

@@ -75,10 +75,10 @@ public class TestSubmitRule implements RestModifyView<RevisionResource, TestSubm
     }
     input.filters = MoreObjects.firstNonNull(input.filters, filters);
 
-    ProjectState projectState = projectCache.get(rsrc.getProject());
+    ProjectState projectState =
-    if (projectState == null) {
+        projectCache
-      throw new BadRequestException("project not found");
+            .get(rsrc.getProject())
-    }
+            .orElseThrow(() -> new BadRequestException("project not found " + rsrc.getProject()));
     ChangeData cd = changeDataFactory.create(rsrc.getNotes());
     SubmitRecord record =
         prologRule.evaluate(

java/com/google/gerrit/server/restapi/config/ListTasks.java

@@ -41,6 +41,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 
 @Singleton
@@ -85,8 +86,8 @@ public class ListTasks implements RestReadView<ConfigResource> {
         Boolean visible = visibilityCache.get(task.projectName);
         if (visible == null) {
           Project.NameKey nameKey = Project.nameKey(task.projectName);
-          ProjectState state = projectCache.get(nameKey);
+          Optional<ProjectState> state = projectCache.get(nameKey);
-          if (state == null || !state.statePermitsRead()) {
+          if (!state.isPresent() || !state.get().statePermitsRead()) {
             visible = false;
           } else {
             try {

java/com/google/gerrit/server/restapi/config/TasksCollection.java

@@ -37,6 +37,7 @@ import com.google.gerrit.server.project.ProjectState;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
+import java.util.Optional;
 
 @Singleton
 public class TasksCollection implements ChildCollection<ConfigResource, TaskResource> {
@@ -87,12 +88,12 @@ public class TasksCollection implements ChildCollection<ConfigResource, TaskReso
     Task<?> task = workQueue.getTask(taskId);
     if (task instanceof ProjectTask) {
       Project.NameKey nameKey = ((ProjectTask<?>) task).getProjectNameKey();
-      ProjectState state = projectCache.get(nameKey);
+      Optional<ProjectState> state = projectCache.get(nameKey);
-      if (state == null) {
+      if (!state.isPresent()) {
         throw new ResourceNotFoundException(String.format("project %s not found", nameKey));
       }
 
-      state.checkStatePermitsRead();
+      state.get().checkStatePermitsRead();
 
       try {
         permissionBackend.user(user).project(nameKey).check(ProjectPermission.ACCESS);

java/com/google/gerrit/server/restapi/project/ListProjects.java

@@ -75,7 +75,6 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
-import java.util.Objects;
 import java.util.Optional;
 import java.util.SortedMap;
 import java.util.SortedSet;
@@ -610,7 +609,8 @@ public class ListProjects implements RestReadView<TopLevelResource> {
   private Stream<ProjectState> filter(PermissionBackend.WithUser perm) throws BadRequestException {
     return StreamSupport.stream(scan().spliterator(), false)
         .map(projectCache::get)
-        .filter(Objects::nonNull)
+        .filter(Optional::isPresent)
+        .map(Optional::get)
         .filter(p -> permissionCheck(p, perm));
   }
 

java/com/google/gerrit/server/restapi/project/SetParent.java

@@ -156,10 +156,14 @@ public class SetParent
 
     newParent = Strings.emptyToNull(newParent);
     if (newParent != null) {
-      ProjectState parent = cache.get(Project.nameKey(newParent));
+      Project.NameKey newParentNameKey = Project.nameKey(newParent);
-      if (parent == null) {
+      ProjectState parent =
-        throw new UnprocessableEntityException("parent project " + newParent + " not found");
+          cache
-      }
+              .get(newParentNameKey)
+              .orElseThrow(
+                  () ->
+                      new UnprocessableEntityException(
+                          "parent project " + newParentNameKey + " not found"));
 
       if (parent.getName().equals(project.get())) {
         throw new ResourceConflictException("cannot set parent to self");

java/com/google/gerrit/server/rules/DefaultSubmitRule.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.server.rules;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.data.LabelFunction;
@@ -63,11 +64,12 @@ public final class DefaultSubmitRule implements SubmitRule {
 
   @Override
   public Optional<SubmitRecord> evaluate(ChangeData cd) {
-    ProjectState projectState = projectCache.get(cd.project());
+    ProjectState projectState =
+        projectCache.get(cd.project()).orElseThrow(illegalState(cd.project()));
 
     // In case at least one project has a rules.pl file, we let Prolog handle it.
     // The Prolog rules engine will also handle the labels for us.
-    if (projectState == null || projectState.hasPrologRules()) {
+    if (projectState.hasPrologRules()) {
       return Optional.empty();
     }
 

java/com/google/gerrit/server/rules/PrologRule.java

@@ -14,6 +14,8 @@
 
 package com.google.gerrit.server.rules;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
+
 import com.google.gerrit.common.data.SubmitRecord;
 import com.google.gerrit.common.data.SubmitTypeRecord;
 import com.google.gerrit.server.project.ProjectCache;
@@ -36,9 +38,10 @@ public class PrologRule implements SubmitRule {
 
   @Override
   public Optional<SubmitRecord> evaluate(ChangeData cd) {
-    ProjectState projectState = projectCache.get(cd.project());
+    ProjectState projectState =
+        projectCache.get(cd.project()).orElseThrow(illegalState(cd.project()));
     // We only want to run the Prolog engine if we have at least one rules.pl file to use.
-    if ((projectState == null || !projectState.hasPrologRules())) {
+    if (!projectState.hasPrologRules()) {
       return Optional.empty();
     }
 

java/com/google/gerrit/server/rules/PrologRuleEvaluator.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.server.rules;
 
 import static com.google.common.base.Preconditions.checkState;
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static com.google.gerrit.server.project.SubmitRuleEvaluator.createRuleError;
 import static com.google.gerrit.server.project.SubmitRuleEvaluator.defaultRuleError;
 import static com.google.gerrit.server.project.SubmitRuleEvaluator.defaultTypeError;
@@ -115,7 +116,7 @@ public class PrologRuleEvaluator {
     this.cd = cd;
     this.opts = options;
 
-    this.projectState = projectCache.get(cd.project());
+    this.projectState = projectCache.get(cd.project()).orElseThrow(illegalState(cd.project()));
   }
 
   private static Term toListTerm(List<Term> terms) {

java/com/google/gerrit/server/submit/MergeOpRepoManager.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.server.submit;
 
 import static com.google.common.base.Preconditions.checkState;
+import static com.google.gerrit.server.project.ProjectCache.noSuchProject;
 import static java.util.Objects.requireNonNull;
 
 import com.google.common.collect.Maps;
@@ -185,10 +186,7 @@ public class MergeOpRepoManager implements AutoCloseable {
       return openRepos.get(project);
     }
 
-    ProjectState projectState = projectCache.get(project);
+    ProjectState projectState = projectCache.get(project).orElseThrow(noSuchProject(project));
-    if (projectState == null) {
-      throw new NoSuchProjectException(project);
-    }
     try {
       OpenRepo or = new OpenRepo(repoManager.openRepository(project), projectState);
       openRepos.put(project, or);

java/com/google/gerrit/server/submit/SubmitDryRun.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.submit;
 
+import static com.google.gerrit.server.project.ProjectCache.noSuchProject;
 import static java.util.stream.Collectors.toSet;
 
 import com.google.common.collect.ImmutableSet;
@@ -156,10 +157,6 @@ public class SubmitDryRun {
   }
 
   private ProjectState getProject(BranchNameKey branch) throws NoSuchProjectException {
-    ProjectState p = projectCache.get(branch.project());
+    return projectCache.get(branch.project()).orElseThrow(noSuchProject(branch.project()));
-    if (p == null) {
-      throw new NoSuchProjectException(branch.project());
-    }
-    return p;
   }
 }

java/com/google/gerrit/server/submit/SubmitStrategy.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.server.submit;
 
 import static com.google.common.collect.ImmutableMap.toImmutableMap;
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.util.Objects.requireNonNull;
 
 import com.google.common.collect.ImmutableMap;
@@ -200,9 +201,7 @@ public abstract class SubmitStrategy {
       this.dryrun = dryrun;
 
       this.project =
-          requireNonNull(
+          projectCache.get(destBranch.project()).orElseThrow(illegalState(destBranch.project()));
-              projectCache.get(destBranch.project()),
-              () -> String.format("project not found: %s", destBranch.project()));
       this.mergeSorter =
           new MergeSorter(caller, rw, alreadyAccepted, canMergeFlag, queryProvider, incoming);
       this.rebaseSorter =

java/com/google/gerrit/server/submit/SubmitStrategyOp.java

@@ -17,6 +17,7 @@ package com.google.gerrit.server.submit;
 import static com.google.common.base.MoreObjects.firstNonNull;
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.gerrit.server.notedb.ReviewerStateInternal.REVIEWER;
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.util.Comparator.comparing;
 import static java.util.Objects.requireNonNull;
 
@@ -486,7 +487,8 @@ abstract class SubmitStrategyOp implements BatchUpdateOp {
       // per project even if multiple changes to refs/meta/config are submitted.
       if (RefNames.REFS_CONFIG.equals(getDest().branch())) {
         args.projectCache.evict(getProject());
-        ProjectState p = args.projectCache.get(getProject());
+        ProjectState p =
+            args.projectCache.get(getProject()).orElseThrow(illegalState(getProject()));
         try (Repository git = args.repoManager.openRepository(getProject())) {
           git.setGitwebDescription(p.getProject().getDescription());
         } catch (IOException e) {

java/com/google/gerrit/server/submit/SubmoduleOp.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.submit;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.util.Comparator.comparing;
 import static java.util.stream.Collectors.toList;
 
@@ -362,7 +363,11 @@ public class SubmoduleOp {
     logger.atFine().log("Calculating possible superprojects for %s", srcBranch);
     Collection<SubmoduleSubscription> ret = new ArrayList<>();
     Project.NameKey srcProject = srcBranch.project();
-    for (SubscribeSection s : projectCache.get(srcProject).getSubscribeSections(srcBranch)) {
+    for (SubscribeSection s :
+        projectCache
+            .get(srcProject)
+            .orElseThrow(illegalState(srcProject))
+            .getSubscribeSections(srcBranch)) {
       logger.atFine().log("Checking subscribe section %s", s);
       Collection<BranchNameKey> branches = getDestinationBranches(srcBranch, s);
       for (BranchNameKey targetBranch : branches) {

java/com/google/gerrit/sshd/commands/SetParentCommand.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.sshd.commands;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.util.stream.Collectors.toList;
 
 import com.google.gerrit.entities.Project;
@@ -37,6 +38,7 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 import org.kohsuke.args4j.Argument;
 import org.kohsuke.args4j.Option;
@@ -117,7 +119,7 @@ final class SetParentCommand extends SshCommand {
 
     for (Project.NameKey nameKey : childProjects) {
       final String name = nameKey.get();
-      ProjectState project = projectCache.get(nameKey);
+      ProjectState project = projectCache.get(nameKey).orElseThrow(illegalState(nameKey));
       try {
         setParent.apply(new ProjectResource(project, user), parentInput(newParentKey.get()));
       } catch (AuthException e) {
@@ -177,10 +179,10 @@ final class SetParentCommand extends SshCommand {
   }
 
   private Set<Project.NameKey> getAllParents(Project.NameKey projectName) {
-    ProjectState ps = projectCache.get(projectName);
+    Optional<ProjectState> ps = projectCache.get(projectName);
-    if (ps == null) {
+    if (!ps.isPresent()) {
       return Collections.emptySet();
     }
-    return ps.parents().transform(ProjectState::getNameKey).toSet();
+    return ps.get().parents().transform(ProjectState::getNameKey).toSet();
   }
 }

java/com/google/gerrit/sshd/commands/UploadArchive.java

@@ -14,8 +14,8 @@
 
 package com.google.gerrit.sshd.commands;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.nio.charset.StandardCharsets.UTF_8;
-import static java.util.Objects.requireNonNull;
 
 import com.google.common.base.Splitter;
 import com.google.common.collect.ImmutableMap;
@@ -245,8 +245,8 @@ public class UploadArchive extends AbstractGitCommand {
   }
 
   private boolean canRead(ObjectId revId) throws IOException, PermissionBackendException {
-    ProjectState projectState = projectCache.get(projectName);
+    ProjectState projectState =
-    requireNonNull(projectState, () -> String.format("Failed to load project %s", projectName));
+        projectCache.get(projectName).orElseThrow(illegalState(projectName));
 
     if (!projectState.statePermitsRead()) {
       return false;

javatests/com/google/gerrit/acceptance/rest/project/CreateProjectIT.java

@@ -91,9 +91,9 @@ public class CreateProjectIT extends AbstractDaemonTest {
     // for more extensive coverage of the LabelTypeInfo.
     assertThat(p.labels).hasSize(1);
 
-    ProjectState projectState = projectCache.get(Project.nameKey(newProjectName));
+    Optional<ProjectState> projectState = projectCache.get(Project.nameKey(newProjectName));
-    assertThat(projectState).isNotNull();
+    assertThat(projectState).isPresent();
-    assertProjectInfo(projectState.getProject(), p);
+    assertProjectInfo(projectState.get().getProject(), p);
     assertHead(newProjectName, "refs/heads/master");
   }
 
@@ -167,9 +167,9 @@ public class CreateProjectIT extends AbstractDaemonTest {
     String newProjectName = name("newProject");
     ProjectInfo p = gApi.projects().create(newProjectName).get();
     assertThat(p.name).isEqualTo(newProjectName);
-    ProjectState projectState = projectCache.get(Project.nameKey(newProjectName));
+    Optional<ProjectState> projectState = projectCache.get(Project.nameKey(newProjectName));
-    assertThat(projectState).isNotNull();
+    assertThat(projectState).isPresent();
-    assertProjectInfo(projectState.getProject(), p);
+    assertProjectInfo(projectState.get().getProject(), p);
     assertHead(newProjectName, "refs/heads/master");
     assertThat(readProjectConfig(newProjectName))
         .hasValue("[access]\n\tinheritFrom = All-Projects\n[submit]\n\taction = inherit\n");
@@ -180,9 +180,9 @@ public class CreateProjectIT extends AbstractDaemonTest {
     String newProjectName = name("newProject");
     ProjectInfo p = gApi.projects().create(newProjectName + ".git").get();
     assertThat(p.name).isEqualTo(newProjectName);
-    ProjectState projectState = projectCache.get(Project.nameKey(newProjectName));
+    Optional<ProjectState> projectState = projectCache.get(Project.nameKey(newProjectName));
-    assertThat(projectState).isNotNull();
+    assertThat(projectState).isPresent();
-    assertProjectInfo(projectState.getProject(), p);
+    assertProjectInfo(projectState.get().getProject(), p);
     assertHead(newProjectName, "refs/heads/master");
   }
 
@@ -191,9 +191,9 @@ public class CreateProjectIT extends AbstractDaemonTest {
     String newProjectName = name("newProject");
     ProjectInfo p = gApi.projects().create(newProjectName + "/").get();
     assertThat(p.name).isEqualTo(newProjectName);
-    ProjectState projectState = projectCache.get(Project.nameKey(newProjectName));
+    Optional<ProjectState> projectState = projectCache.get(Project.nameKey(newProjectName));
-    assertThat(projectState).isNotNull();
+    assertThat(projectState).isPresent();
-    assertProjectInfo(projectState.getProject(), p);
+    assertProjectInfo(projectState.get().getProject(), p);
     assertHead(newProjectName, "refs/heads/master");
   }
 
@@ -202,9 +202,9 @@ public class CreateProjectIT extends AbstractDaemonTest {
     String newProjectName = name("newProject/newProject");
     ProjectInfo p = gApi.projects().create(newProjectName).get();
     assertThat(p.name).isEqualTo(newProjectName);
-    ProjectState projectState = projectCache.get(Project.nameKey(newProjectName));
+    Optional<ProjectState> projectState = projectCache.get(Project.nameKey(newProjectName));
-    assertThat(projectState).isNotNull();
+    assertThat(projectState).isPresent();
-    assertProjectInfo(projectState.getProject(), p);
+    assertProjectInfo(projectState.get().getProject(), p);
     assertHead(newProjectName, "refs/heads/master");
   }
 
@@ -221,7 +221,7 @@ public class CreateProjectIT extends AbstractDaemonTest {
     in.requireChangeId = InheritableBoolean.TRUE;
     ProjectInfo p = gApi.projects().create(in).get();
     assertThat(p.name).isEqualTo(newProjectName);
-    Project project = projectCache.get(Project.nameKey(newProjectName)).getProject();
+    Project project = projectCache.get(Project.nameKey(newProjectName)).get().getProject();
     assertProjectInfo(project, p);
     assertThat(project.getDescription()).isEqualTo(in.description);
     assertThat(project.getConfiguredSubmitType()).isEqualTo(in.submitType);
@@ -247,7 +247,7 @@ public class CreateProjectIT extends AbstractDaemonTest {
     in.name = childName;
     in.parent = parentName;
     gApi.projects().create(in);
-    Project project = projectCache.get(Project.nameKey(childName)).getProject();
+    Project project = projectCache.get(Project.nameKey(childName)).get().getProject();
     assertThat(project.getParentName()).isEqualTo(in.parent);
   }
 
@@ -275,12 +275,13 @@ public class CreateProjectIT extends AbstractDaemonTest {
                 .getId()
                 .get())); // by ID
     gApi.projects().create(in);
-    ProjectState projectState = projectCache.get(Project.nameKey(newProjectName));
+    Optional<ProjectState> projectState = projectCache.get(Project.nameKey(newProjectName));
     Set<AccountGroup.UUID> expectedOwnerIds = Sets.newHashSetWithExpectedSize(3);
     expectedOwnerIds.add(SystemGroupBackend.ANONYMOUS_USERS);
     expectedOwnerIds.add(SystemGroupBackend.REGISTERED_USERS);
     expectedOwnerIds.add(groupUuid("Administrators"));
-    assertProjectOwners(expectedOwnerIds, projectState);
+    assertThat(projectState).isPresent();
+    assertProjectOwners(expectedOwnerIds, projectState.get());
   }
 
   @Test
@@ -367,7 +368,7 @@ public class CreateProjectIT extends AbstractDaemonTest {
 
   @Test
   public void createProjectWithCreateProjectCapabilityAndParentNotVisible() throws Exception {
-    Project parent = projectCache.get(allProjects).getProject();
+    Project parent = projectCache.get(allProjects).get().getProject();
     parent.setState(com.google.gerrit.extensions.client.ProjectState.HIDDEN);
     projectOperations
         .allProjectsForUpdate()

javatests/com/google/gerrit/acceptance/rest/project/GetChildProjectIT.java

@@ -49,7 +49,7 @@ public class GetChildProjectIT extends AbstractDaemonTest {
     Project.NameKey child = projectOperations.newProject().create();
     ProjectInfo childInfo = gApi.projects().name(allProjects.get()).child(child.get()).get();
 
-    assertProjectInfo(projectCache.get(child).getProject(), childInfo);
+    assertProjectInfo(projectCache.get(child).get().getProject(), childInfo);
   }
 
   @Test
@@ -67,7 +67,7 @@ public class GetChildProjectIT extends AbstractDaemonTest {
 
     ProjectInfo grandChildInfo =
         gApi.projects().name(allProjects.get()).child(grandChild.get()).get(true);
-    assertProjectInfo(projectCache.get(grandChild).getProject(), grandChildInfo);
+    assertProjectInfo(projectCache.get(grandChild).get().getProject(), grandChildInfo);
   }
 
   private void assertChildNotFound(Project.NameKey parent, String child) throws Exception {

javatests/com/google/gerrit/acceptance/rest/project/ProjectLevelConfigIT.java

@@ -50,13 +50,13 @@ public class ProjectLevelConfigIT extends AbstractDaemonTest {
             admin.newIdent(), testRepo, "Create Project Level Config", configName, cfg.toText());
     push.to(RefNames.REFS_CONFIG);
 
-    ProjectState state = projectCache.get(project);
+    ProjectState state = projectCache.get(project).get();
     assertThat(state.getConfig(configName).get().toText()).isEqualTo(cfg.toText());
   }
 
   @Test
   public void nonExistingConfig() {
-    ProjectState state = projectCache.get(project);
+    ProjectState state = projectCache.get(project).get();
     assertThat(state.getConfig("test.config").get().toText()).isEqualTo("");
   }
 
@@ -99,7 +99,7 @@ public class ProjectLevelConfigIT extends AbstractDaemonTest {
         .to(RefNames.REFS_CONFIG)
         .assertOkStatus();
 
-    ProjectState state = projectCache.get(childProject);
+    ProjectState state = projectCache.get(childProject).get();
 
     Config expectedCfg = new Config();
     expectedCfg.setString("s1", null, "k1", "childValue1");
@@ -158,7 +158,7 @@ public class ProjectLevelConfigIT extends AbstractDaemonTest {
         .to(RefNames.REFS_CONFIG)
         .assertOkStatus();
 
-    ProjectState state = projectCache.get(childProject);
+    ProjectState state = projectCache.get(childProject).get();
 
     Config expectedCfg = new Config();
     expectedCfg.setStringList("s1", null, "k1", Arrays.asList("childValue1", "parentValue1"));

javatests/com/google/gerrit/acceptance/ssh/CreateProjectIT.java

@@ -15,11 +15,13 @@
 package com.google.gerrit.acceptance.ssh;
 
 import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.Truth8.assertThat;
 
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.UseSsh;
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.server.project.ProjectState;
+import java.util.Optional;
 import org.junit.Test;
 
 @UseSsh
@@ -33,8 +35,8 @@ public class CreateProjectIT extends AbstractDaemonTest {
     adminSshSession.exec(
         "gerrit create-project --branch master --owner " + newGroupName + " " + newProjectName);
     adminSshSession.assertSuccess();
-    ProjectState projectState = projectCache.get(Project.nameKey(newProjectName));
+    Optional<ProjectState> projectState = projectCache.get(Project.nameKey(newProjectName));
-    assertThat(projectState).isNotNull();
+    assertThat(projectState).isPresent();
   }
 
   @Test
@@ -46,8 +48,8 @@ public class CreateProjectIT extends AbstractDaemonTest {
     adminSshSession.exec(
         "gerrit create-project --branch master --owner " + wrongGroupName + " " + newProjectName);
     adminSshSession.assertFailure();
-    ProjectState projectState = projectCache.get(Project.nameKey(newProjectName));
+    Optional<ProjectState> projectState = projectCache.get(Project.nameKey(newProjectName));
-    assertThat(projectState).isNull();
+    assertThat(projectState).isEmpty();
   }
 
   @Test
@@ -62,9 +64,9 @@ public class CreateProjectIT extends AbstractDaemonTest {
             + newProjectName
             + ".git");
     adminSshSession.assertSuccess();
-    ProjectState projectState = projectCache.get(Project.nameKey(newProjectName));
+    Optional<ProjectState> projectState = projectCache.get(Project.nameKey(newProjectName));
-    assertThat(projectState).isNotNull();
+    assertThat(projectState).isPresent();
-    assertThat(projectState.getName()).isEqualTo(newProjectName);
+    assertThat(projectState.get().getName()).isEqualTo(newProjectName);
   }
 
   @Test
@@ -79,8 +81,8 @@ public class CreateProjectIT extends AbstractDaemonTest {
             + newProjectName
             + "/");
     adminSshSession.assertSuccess();
-    ProjectState projectState = projectCache.get(Project.nameKey(newProjectName));
+    Optional<ProjectState> projectState = projectCache.get(Project.nameKey(newProjectName));
-    assertThat(projectState).isNotNull();
+    assertThat(projectState).isPresent();
-    assertThat(projectState.getName()).isEqualTo(newProjectName);
+    assertThat(projectState.get().getName()).isEqualTo(newProjectName);
   }
 }

javatests/com/google/gerrit/server/permissions/RefControlTest.java

@@ -33,6 +33,7 @@ import static com.google.gerrit.entities.RefNames.REFS_CONFIG;
 import static com.google.gerrit.server.group.SystemGroupBackend.ANONYMOUS_USERS;
 import static com.google.gerrit.server.group.SystemGroupBackend.CHANGE_OWNER;
 import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static com.google.gerrit.testing.GerritJUnit.assertThrows;
 
 import com.google.common.collect.Lists;
@@ -1165,7 +1166,7 @@ public class RefControlTest {
   }
 
   private ProjectState getProjectState(Project.NameKey nameKey) throws Exception {
-    return projectCache.checkedGet(nameKey, true);
+    return projectCache.get(nameKey).orElseThrow(illegalState(nameKey));
   }
 
   private ProjectControl user(Project.NameKey localKey, AccountGroup.UUID... memberOf)

javatests/com/google/gerrit/server/project/CommitsCollectionTest.java

@@ -207,7 +207,7 @@ public class CommitsCollectionTest {
   }
 
   private ProjectState readProjectState() throws Exception {
-    return projectCache.get(project);
+    return projectCache.get(project).get();
   }
 
   private void setUpPermissions() throws Exception {