Maven parsing fails for managed dependency entries without version tag

Parsing a (surprisingly valid) pom like the below (with assertions enabled) causes the parser to throw an exception.

<?xml version="1.0" encoding="UTF-8"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <modelVersion>4.0.0</modelVersion>
  <groupId>test</groupId>
  <artifactId>test</artifactId>
  <version>1.0-SNAPSHOT</version>
  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>com.fasterxml.jackson</groupId>
        <artifactId>jackson-bom</artifactId>
        <version>2.11.1</version>
        <scope>import</scope>
        <type>pom</type>
      </dependency>

      <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <!-- no version! -->
      </dependency>
    </dependencies>
  </dependencyManagement>
</project>

java.lang.AssertionError
	at org.openrewrite.maven.internal.RawMavenResolver.processDependencyManagement(RawMavenResolver.java:158)
	at org.openrewrite.maven.internal.RawMavenResolver.processTask(RawMavenResolver.java:131)
	at org.openrewrite.maven.internal.RawMavenResolver.resolve(RawMavenResolver.java:114)
	at org.openrewrite.maven.internal.RawMavenResolver.resolve(RawMavenResolver.java:99)
	at org.openrewrite.maven.internal.RawMavenResolver.resolve(RawMavenResolver.java:77)
	at org.openrewrite.maven.MavenParser.parseInputs(MavenParser.java:90)
	at org.openrewrite.Parser.parse(Parser.java:39)

[jkschneider]

Hi @danielnorberg. Thanks for the report and all the explanation. I’ve removed the assert and a couple later checks as well that assumed that there would be a version. In addition, wrote a cleanup recipe for Maven that does what I suppose you want to do as well, which is to remove these dependencyManagement dependencies which have no versions.

It is available to run as org.openrewrite.maven.cleanup.DependencyManagementDependencyRequiresVersion.

Thanks again!

[danielnorberg]

I have yet to spot a valid use of this maven behavior in the wild. In our case we encountered pom files written like this (likely due to mistakes, probably not intentional) in internal repositories and I wanted to make our automated pom refactoring tool (built using openrewrite, operating daily on thousands of repositories) fix these pom files by removing dependency management entries without version tags.

In fact I only noticed that openrewrite asserts that version tag is present when adding automated tests (that run with assertions enabled) to our refactoring tool to cover this use case. With assertions disabled parsing seems to complete successfully (although I haven’t verified that the result is “correct”).