Treat empty username as non-existing username

Some callers of AccountState#getUserName and
IdentifiedUser#getUserName() explicitly check that the user name is
non-empty to then treat it the same way as a non-existing user name.
Save the callers from this effort and move this check to a generic
place.

Change-Id: I65cc3403405ec702a0c30ca1f4b17555d97c1315
Signed-off-by: Edwin Kempin <ekempin@google.com>

java/com/google/gerrit/httpd/GetUserFilter.java

@@ -66,7 +66,7 @@ public class GetUserFilter implements Filter {
     CurrentUser user = userProvider.get();
     if (user != null && user.isIdentifiedUser()) {
       IdentifiedUser who = user.asIdentifiedUser();
-      if (who.getUserName() != null && !who.getUserName().isEmpty()) {
+      if (who.getUserName() != null) {
         req.setAttribute(REQ_ATTR_KEY, who.getUserName());
       } else {
         req.setAttribute(REQ_ATTR_KEY, "a/" + who.getAccountId());

java/com/google/gerrit/httpd/gitweb/GitwebServlet.java

@@ -575,7 +575,7 @@ class GitwebServlet extends HttpServlet {
       IdentifiedUser u = userProvider.get().asIdentifiedUser();
       String user = u.getUserName();
       env.set("GERRIT_USER_NAME", user);
-      if (user != null && !user.isEmpty()) {
+      if (user != null) {
         remoteUser = user;
       } else {
         remoteUser = "account-" + u.getAccountId();

java/com/google/gerrit/pgm/http/jetty/ProjectQoSFilter.java

@@ -226,7 +226,7 @@ public class ProjectQoSFilter implements Filter {
       CurrentUser who = user.get();
       if (who.isIdentifiedUser()) {
         String name = who.asIdentifiedUser().getUserName();
-        if (name != null && !name.isEmpty()) {
+        if (name != null) {
           userName = " (" + name + ")";
         }
       }

java/com/google/gerrit/server/IdentifiedUser.java

@@ -291,7 +291,10 @@ public class IdentifiedUser extends CurrentUser {
     return accountId;
   }
 
-  /** @return the user's user name; null if one has not been selected/assigned. */
+  /**
+   * @return the user's user name; null if one has not been selected/assigned or if the user name is
+   *     empty.
+   */
   @Override
   @Nullable
   public String getUserName() {
@@ -380,7 +383,7 @@ public class IdentifiedUser extends CurrentUser {
       // necessarily want to publish through Git records.
       //
       String user = getUserName();
-      if (user == null || user.isEmpty()) {
+      if (user == null) {
         user = "account-" + ua.getId().toString();
       }
 

java/com/google/gerrit/server/account/AccountManager.java

@@ -232,7 +232,7 @@ public class AccountManager {
 
     if (!realm.allowsEdit(AccountFieldName.USER_NAME)
         && who.getUserName() != null
-        && !Objects.equals(user.getUserName(), who.getUserName())) {
+        && !Objects.equals(user.getUserName(), Strings.emptyToNull(who.getUserName()))) {
       log.warn(
           String.format(
               "Not changing already set username %s to %s", user.getUserName(), who.getUserName()));

java/com/google/gerrit/server/account/AccountState.java

@@ -195,6 +195,9 @@ public class AccountState {
    * Get the username, if one has been declared for this user.
    *
    * <p>The username is the {@link ExternalId} using the scheme {@link ExternalId#SCHEME_USERNAME}.
+   *
+   * @return the username, {@link Optional#empty()} if the user has no username, or if the username
+   *     is empty
    */
   public Optional<String> getUserName() {
     return userName;

java/com/google/gerrit/server/account/externalids/ExternalId.java

@@ -62,6 +62,7 @@ public abstract class ExternalId implements Serializable {
         .stream()
         .filter(e -> e.isScheme(SCHEME_USERNAME))
         .map(e -> e.key().id())
+        .filter(u -> !Strings.isNullOrEmpty(u))
         .findFirst();
   }
 

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

@@ -204,7 +204,7 @@ final class ShowConnections extends SshCommand {
       IdentifiedUser u = user.asIdentifiedUser();
 
       if (!numeric) {
-        Optional<String> name = u.state().getUserName().filter(n -> !n.isEmpty());
+        Optional<String> name = u.state().getUserName();
         if (name.isPresent()) {
           return name.get();
         }

plugins/download-commands

@@ -1 +1 @@
-Subproject commit ddbd12781fd4b3156625608ee608950ab370b9a3
+Subproject commit 771695a0903463aa91337323db136b68535e6746