Don't NPE when nomulus tool is run without a subcommand (#564)

* Don't NPE when nomulus tool is run without a subcommand

This occurred when an environment was specified but without a subcommand. Now,
the list of valid subcommands is outputted instead of seeing a generic NPE.

This also makes some formatting changes in other files that were causing the
incremental format check to fail.

* Try AppEngineRule

core/src/main/java/google/registry/persistence/converter/VKeyConverter.java

@@ -18,9 +18,7 @@ import google.registry.persistence.VKey;
 import javax.annotation.Nullable;
 import javax.persistence.AttributeConverter;
 
-/**
- * Converts VKey to a string column.
- */
+/** Converts VKey to a string column. */
 public abstract class VKeyConverter<T> implements AttributeConverter<VKey<T>, String> {
   @Override
   @Nullable
@@ -34,8 +32,6 @@ public abstract class VKeyConverter<T> implements AttributeConverter<VKey<T>, St
     return dbData == null ? null : VKey.createSql(getAttributeClass(), dbData);
   }
 
-  /**
-   * Returns the class of the attribute.
-   */
+  /** Returns the class of the attribute. */
   protected abstract Class<T> getAttributeClass();
 }

core/src/main/java/google/registry/tools/DomainLockUtils.java

@@ -153,8 +153,8 @@ public final class DomainLockUtils {
   /**
    * Creates and applies a lock in one step.
    *
-   * <p>This should only be used for admin actions, e.g. Nomulus tool commands or relocks.
-   * Note: in the case of relocks, isAdmin is determined by the previous lock.
+   * <p>This should only be used for admin actions, e.g. Nomulus tool commands or relocks. Note: in
+   * the case of relocks, isAdmin is determined by the previous lock.
    */
   public RegistryLock administrativelyApplyLock(
       String domainName, String registrarId, @Nullable String registrarPocId, boolean isAdmin) {
@@ -175,7 +175,7 @@ public final class DomainLockUtils {
 
   /**
    * Creates and applies an unlock in one step.
-   * 
+   *
    * <p>This should only be used for admin actions, e.g. Nomulus tool commands.
    */
   public RegistryLock administrativelyApplyUnlock(

core/src/main/java/google/registry/tools/RegistryCli.java

@@ -132,10 +132,8 @@ final class RegistryCli implements AutoCloseable, CommandRunner {
       jcommander.parse(args);
     } catch (ParameterException e) {
       // If we failed to fully parse the command but at least found a valid command name, show only
-      // the usage for that command. Otherwise, show full usage. Either way, rethrow the error.
-      if (jcommander.getParsedCommand() == null) {
-        jcommander.usage();
-      } else {
+      // the usage for that command.
+      if (jcommander.getParsedCommand() != null) {
         jcommander.usage(jcommander.getParsedCommand());
       }
       // Don't rethrow if we said: nomulus command --help
@@ -144,8 +142,13 @@ final class RegistryCli implements AutoCloseable, CommandRunner {
       }
       throw e;
     }
-
-    if (showAllCommands) {
+    String parsedCommand = jcommander.getParsedCommand();
+    // Show the list of all commands either if requested or if no subcommand name was specified
+    // (which does not throw a ParameterException parse error above).
+    if (showAllCommands || parsedCommand == null) {
+      if (parsedCommand == null) {
+        System.out.println("The list of available subcommands is:");
+      }
       commands.keySet().forEach(System.out::println);
       return;
     }
@@ -161,8 +164,7 @@ final class RegistryCli implements AutoCloseable, CommandRunner {
     // retrieving the first (and, by virtue of our usage, only) object from it.
     Command command =
         (Command)
-            Iterables.getOnlyElement(
-                jcommander.getCommands().get(jcommander.getParsedCommand()).getObjects());
+            Iterables.getOnlyElement(jcommander.getCommands().get(parsedCommand).getObjects());
     loggingParams.configureLogging();  // Must be called after parameters are parsed.
 
     try {

core/src/main/java/google/registry/ui/server/RegistrarFormFields.java

@@ -186,9 +186,7 @@ public final class RegistrarFormFields {
           .build();
 
   public static final FormField<String, String> REGISTRY_LOCK_EMAIL_ADDRESS_FIELD =
-      FormFields.EMAIL
-          .asBuilderNamed("registryLockEmailAddress")
-          .build();
+      FormFields.EMAIL.asBuilderNamed("registryLockEmailAddress").build();
 
   public static final FormField<Boolean, Boolean> CONTACT_VISIBLE_IN_WHOIS_AS_ADMIN_FIELD =
       FormField.named("visibleInWhoisAsAdmin", Boolean.class)