Custom theme: common resources cause NullPointerExceptions

Extending the server
1

Hi all,

I am creating a custom theme with both login and account pages. I want to reuse resources for both types, so I created a common folder, just like in the default keycloak theme:

mytheme/
├── common/
│   └── resources/
│       └── img/
│           └── favicon.ico
└── login/
    ├── theme.properties
    └── resources/
        └── css/
            └── style.css

My theme.properties looks like this:

parent=base
styles=css/style.css
import=common/mytheme

I deploy the theme as an archive as described in the docs. This used to work fine before adding the import=common/mytheme line. However now I get a 500 server error whenever a login page is generated:

[org.keycloak.services] (default task-3) KC-SERVICES0013: Failed authentication: java.lang.NullPointerException
	at org.keycloak.keycloak-services@12.0.4//org.keycloak.theme.DefaultThemeManager$ExtendingTheme.getMessages(DefaultThemeManager.java:256)
	at org.keycloak.keycloak-services@12.0.4//org.keycloak.theme.DefaultThemeManager$ExtendingTheme.getMessages(DefaultThemeManager.java:247)
	at org.keycloak.keycloak-services@12.0.4//org.keycloak.theme.DefaultThemeManager$ExtendingTheme.getMessages(DefaultThemeManager.java:236)
	at org.keycloak.keycloak-services@12.0.4//org.keycloak.forms.login.freemarker.FreeMarkerLoginFormsProvider.handleThemeResources(FreeMarkerLoginFormsProvider.java:306)
    ...

ERROR [org.keycloak.services.error.KeycloakErrorHandler] (default task-3) Failed to create error page: java.lang.NullPointerException
	at org.keycloak.keycloak-services@12.0.4//org.keycloak.theme.DefaultThemeManager$ExtendingTheme.getMessages(DefaultThemeManager.java:256)
	at org.keycloak.keycloak-services@12.0.4//org.keycloak.theme.DefaultThemeManager$ExtendingTheme.getMessages(DefaultThemeManager.java:247)
	at org.keycloak.keycloak-services@12.0.4//org.keycloak.theme.DefaultThemeManager$ExtendingTheme.getMessages(DefaultThemeManager.java:236)
	at org.keycloak.keycloak-services@12.0.4//org.keycloak.services.error.KeycloakErrorHandler.initAttributes(KeycloakErrorHandler.java:150)
	at org.keycloak.keycloak-services@12.0.4//org.keycloak.services.error.KeycloakErrorHandler.toResponse(KeycloakErrorHandler.java:86)
    ...

Is this a bug? Can I only import a common folder within the same theme if the theme folder is copied in the server’s themes folder?