[I] maven-shade-plugin dependency-reduced-pom.xml causes parent cycle error in Maven 4 [maven]

["gnodet (via GitHub)" <gi...@apache.org>]

gnodet opened a new issue, #12074:
URL: https://github.com/apache/maven/issues/12074

   ## Summary
   
   The `maven-shade-plugin` generates a `dependency-reduced-pom.xml` that Maven 4's stricter model validator detects as a parent cycle. This works fine in Maven 3.
   
   ## Reproduction
   
   Build any project using `maven-shade-plugin` with a parent POM, e.g., [apache/maven-doxia-converter](https://github.com/apache/maven-doxia-converter):
   
   ```
   mvn package -DskipTests
   ```
   
   ### Expected
   Build succeeds (as it does with Maven 3).
   
   ### Actual
   ```
   [ERROR] Failed to execute goal org.apache.maven.plugins:maven-shade-plugin:3.6.0:shade (default) 
     on project doxia-converter: Error creating shaded jar: 1 problem was for [inherited]:doxia-converter:jar:1.4-SNAPSHOT
       - [FATAL] The parents form a cycle: org.apache.maven.doxia:doxia-tools:43 -> 
         /home/runner/work/maven4-testing/maven4-testing/project/pom.xml -> 
         org.apache.maven.doxia:doxia-tools:43 
         for project [inherited]:doxia-converter:jar:1.4-SNAPSHOT 
         at /home/runner/work/maven4-testing/maven4-testing/project/dependency-reduced-pom.xml
   ```
   
   ## Root Cause
   
   The shade plugin writes `dependency-reduced-pom.xml` which references the parent POM by file path. Maven 4's model builder resolves this path and detects a cycle: the parent POM resolves back to the project itself. Maven 3 was lenient about this during the shade plugin's internal POM re-reading.
   
   ## Affected projects
   
   From maven4-testing across ~960 Apache repositories:
   - maven-doxia-converter (shade 3.6.0)
   - sling-launchpad-comparator (shade 3.6.0)
   - sling-org-apache-sling-models-impl (shade 3.6.1)
   
   All use recent shade plugin versions (3.6.x), so this is not about outdated plugins.
   
   ## Environment
   
   - Maven: 4.0.0-SNAPSHOT (branch `maven-4.0.x-test-fixes`)
   - maven-shade-plugin: 3.6.0 / 3.6.1
   - Java: 17.0.18 (Eclipse Adoptium)
   
   Test results: https://github.com/gnodet/maven4-testing/issues/9934
   
   _Claude Code on behalf of Guillaume Nodet_


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Re: [I] maven-shade-plugin dependency-reduced-pom.xml causes parent cycle error in Maven 4 [maven]

["gnodet (via GitHub)" <gi...@apache.org>]

gnodet closed issue #12074: maven-shade-plugin dependency-reduced-pom.xml causes parent cycle error in Maven 4
URL: https://github.com/apache/maven/issues/12074


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