ascheman opened a new issue, #1286: URL: https://github.com/apache/maven-site-plugin/issues/1286
### Description Since the site descriptor 2.0.0 no longer supplies a default skin, a project whose `src/site/site.xml` (using the `SITE/2.0.0` namespace) declares no `<skin>` fails the site build with a bare `NullPointerException` instead of an actionable message. ### Steps to reproduce Self-contained, no parent POM needed. maven-site-plugin 3.22.0, Maven 4.0.0-rc-5, JDK 21. `pom.xml`: ```xml <project xmlns="http://maven.apache.org/POM/4.0.0";> <modelVersion>4.0.0</modelVersion> <groupId>org.test</groupId> <artifactId>site-skin-npe-repro</artifactId> <version>1</version> <packaging>pom</packaging> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-site-plugin</artifactId> <version>3.22.0</version> </plugin> </plugins> </build> </project> ``` `src/site/site.xml` (no `<skin>`): ```xml <site xmlns="http://maven.apache.org/SITE/2.0.0"; xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; xsi:schemaLocation="http://maven.apache.org/SITE/2.0.0 https://maven.apache.org/xsd/site-2.0.0.xsd";> <body> <menu name="Overview"><item name="Introduction" href="index.html"/></menu> </body> </site> ``` `mvn site` → ``` [ERROR] Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.22.0:site (default-site) ... : skin cannot be null Caused by: java.lang.NullPointerException: skin cannot be null at java.util.Objects.requireNonNull(Objects.java:259) at org.apache.maven.doxia.tools.DefaultSiteTool.getSkinArtifactFromRepository(DefaultSiteTool.java:150) at org.apache.maven.plugins.site.render.AbstractSiteRenderingMojo.createSiteRenderingContext(AbstractSiteRenderingMojo.java:309) at org.apache.maven.plugins.site.render.SiteMojo.renderLocale(SiteMojo.java:141) at org.apache.maven.plugins.site.render.SiteMojo.execute(SiteMojo.java:125) ``` Adding an explicit `<skin>` (e.g. `maven-fluido-skin`) makes the build pass — but nothing in the error tells the user that's the fix. Also hit in the wild on apache/maven-source-plugin master (worked around in apache/maven-source-plugin#310). ### Expected behavior A clear, actionable error — e.g. *"No `<skin>` is declared in the site descriptor. Since site descriptor 2.0.0 no longer supplies a default skin, declare one explicitly (e.g. `org.apache.maven.skins:maven-fluido-skin`)."* — or restore a sensible default when none is configured. ### Notes - The NPE is the `Objects.requireNonNull(skin, "skin cannot be null")` guard in `DefaultSiteTool.getSkinArtifactFromRepository` (doxia-sitetools); `AbstractSiteRenderingMojo` passes a null skin when the descriptor has none. A fix could live here in maven-site-plugin (validate + emit a clear message before the call) and/or in doxia-sitetools (throw a `SiteToolException` with guidance, or default the skin). - Reproduces standalone; parent site descriptors aren't inherited anyway (`mvn site -X` shows `No parent level N site descriptor`, since parent POMs don't publish a site-descriptor artifact). -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
