Support sending review comment emails synchronously

A directExecutor is not a WorkQueue.Executor so the bound type needs
to change, but this is fine, as callers are only using submit.

Turn this on by default for tests. Don't even bother reading the
config in InMemoryModule, but still set the config option as it may
be required in the non-in-memory test path.

Change-Id: Ib48792b585971206452543173f8194a08b46875b

gerrit-server/src/main/java/com/google/gerrit/server/change/EmailReviewComments.java

@@ -24,7 +24,6 @@ import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.git.EmailReviewCommentsExecutor;
-import com.google.gerrit.server.git.WorkQueue.Executor;
 import com.google.gerrit.server.mail.CommentSender;
 import com.google.gerrit.server.patch.PatchSetInfoFactory;
 import com.google.gerrit.server.util.RequestContext;
@@ -43,6 +42,7 @@ import org.slf4j.LoggerFactory;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
+import java.util.concurrent.ExecutorService;
 
 public class EmailReviewComments implements Runnable, RequestContext {
   private static final Logger log = LoggerFactory.getLogger(EmailReviewComments.class);
@@ -57,7 +57,7 @@ public class EmailReviewComments implements Runnable, RequestContext {
         List<PatchLineComment> comments);
   }
 
-  private final Executor sendEmailsExecutor;
+  private final ExecutorService sendEmailsExecutor;
   private final PatchSetInfoFactory patchSetInfoFactory;
   private final CommentSender.Factory commentSenderFactory;
   private final SchemaFactory<ReviewDb> schemaFactory;
@@ -73,7 +73,7 @@ public class EmailReviewComments implements Runnable, RequestContext {
 
   @Inject
   EmailReviewComments (
-      @EmailReviewCommentsExecutor final Executor executor,
+      @EmailReviewCommentsExecutor ExecutorService executor,
       PatchSetInfoFactory patchSetInfoFactory,
       CommentSender.Factory commentSenderFactory,
       SchemaFactory<ReviewDb> schemaFactory,
@@ -103,8 +103,8 @@ public class EmailReviewComments implements Runnable, RequestContext {
 
   @Override
   public void run() {
+    RequestContext old = requestContext.setContext(this);
     try {
-      requestContext.setContext(this);
 
       comments = Lists.newArrayList(comments);
       Collections.sort(comments, new Comparator<PatchLineComment>() {
@@ -138,7 +138,7 @@ public class EmailReviewComments implements Runnable, RequestContext {
     } catch (Exception e) {
       log.error("Cannot email comments for " + patchSet.getId(), e);
     } finally {
-      requestContext.setContext(null);
+      requestContext.setContext(old);
       if (db != null) {
         db.close();
         db = null;

gerrit-server/src/main/java/com/google/gerrit/server/git/ReceiveCommitsExecutorModule.java

@@ -25,6 +25,7 @@ import com.google.inject.Singleton;
 import org.eclipse.jgit.lib.Config;
 
 import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 
@@ -48,9 +49,12 @@ public class ReceiveCommitsExecutorModule extends AbstractModule {
   @Provides
   @Singleton
   @EmailReviewCommentsExecutor
-  public WorkQueue.Executor createEmailReviewCommentsExecutor(
+  public ExecutorService createEmailReviewCommentsExecutor(
       @GerritServerConfig Config config, WorkQueue queues) {
     int poolSize = config.getInt("sendemail", null, "threadPoolSize", 1);
+    if (poolSize == 0) {
+      return MoreExecutors.newDirectExecutorService();
+    }
     return queues.createQueue(poolSize, "EmailReviewComments");
   }
 

gerrit-server/src/test/java/com/google/gerrit/testutil/InMemoryModule.java

@@ -44,7 +44,6 @@ import com.google.gerrit.server.git.EmailReviewCommentsExecutor;
 import com.google.gerrit.server.git.GarbageCollection;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.git.PerThreadRequestScope;
-import com.google.gerrit.server.git.WorkQueue;
 import com.google.gerrit.server.index.ChangeSchemas;
 import com.google.gerrit.server.index.IndexModule.IndexType;
 import com.google.gerrit.server.mail.SignedTokenEmailTokenVerifier;
@@ -94,6 +93,7 @@ public class InMemoryModule extends FactoryModule {
     cfg.setBoolean("index", "lucene", "testInmemory", true);
     cfg.setInt("index", "lucene", "testVersion",
         ChangeSchemas.getLatest().getVersion());
+    cfg.setInt("sendemail", null, "threadPoolSize", 0);
   }
 
   private final Config cfg;
@@ -205,10 +205,8 @@ public class InMemoryModule extends FactoryModule {
   @Provides
   @Singleton
   @EmailReviewCommentsExecutor
-  public WorkQueue.Executor createEmailReviewCommentsExecutor(
-      @GerritServerConfig Config config, WorkQueue queues) {
-    int poolSize = config.getInt("sendemail", null, "threadPoolSize", 1);
-    return queues.createQueue(poolSize, "EmailReviewComments");
+  public ExecutorService createEmailReviewCommentsExecutor() {
+    return MoreExecutors.newDirectExecutorService();
   }
 
   @Provides