ascheman commented on PR #799: URL: https://github.com/apache/maven-shade-plugin/pull/799#issuecomment-5077952077
Thanks @elharo. I dug into this because it touches the dependency-reduced-POM writer (`ShadeMojo.rewriteDependencyReducedPomIfWeHaveReduction` → `PomWriter.write(w, model, true)`), which matters for the Maven 4 direction. I think there's both a concrete bug and an underlying design question worth settling before this moves. **For today's 4.0.0 POMs this is a no-op** — with `modelVersion == 4.0.0`, master and this branch emit identical output (`xmlns=".../POM/4.0.0"` + `maven-v4_0_0.xsd`), which is why CI is green. **For a 4.1.0 build model it produces a self-contradictory POM.** The `xmlns` is hardcoded to 4.0.0, but the `schemaLocation` XSD is still derived from `modelVersion`, and the `<modelVersion>` element is untouched. Feeding `PomWriter.write(w, model, true)` a `modelVersion=4.1.0` model yields: ```xml <project xmlns="http://maven.apache.org/POM/4.0.0"; xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_1_0.xsd";> <modelVersion>4.1.0</modelVersion> </project> ``` — a 4.0.0 namespace paired with a 4.1.0 schema *and* a 4.1.0 `<modelVersion>`. (Maven's own 4.1.0 POMs use `xmlns=".../POM/4.1.0"`, cf. `apache/maven` `pom-4.1.0.xml`.) On master the three agree (`POM/4.1.0` + `maven-v4_1_0.xsd` + `4.1.0`). **The design question underneath:** should shade's dependency-reduced POM be a 4.0.0 (consumer-style) POM even when the build POM is 4.1.0? There's a real case for it — the DRP is consumed by downstream projects (shaded *libraries*), so broad 4.0.0 compatibility is desirable. But if that's the goal, it needs a genuine downgrade (`<modelVersion>4.0.0</modelVersion>` + 4.0.0 XSD + 4.0.0-compatible content), not just an `xmlns` relabel — and it likely overlaps Maven 4's own consumer-POM transformation, which already downgrades a deployed 4.1.0 POM to a 4.0.0 consumer. So the DRP may not need to do this at all. @gnodet — since you own the consumer-POM design: for a 4.1.0 build POM, should shade emit the DRP in the build model version (4.1.0) and let core's consumer-POM transform produce the 4.0.0 consumer, or should the DRP itself be a fully-downgraded 4.0.0 POM? That answer decides the right shape here. As written the change is a no-op for 4.0.0 and inconsistent for 4.1.0, so I don't think it should merge in this form. Happy to share the small probe I used. -- 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]
