Regression in MavenPomDownloader from 8.42.0

[BoykoAlex]

Consider this unit test:

(The test merely attempts to resolve dependencies and check if compile scope has proper number of dependencies)

    @Test
    void resolveDependencies() throws MavenDownloadingExceptions {
        Xml.Document doc = (Xml.Document) MavenParser.builder().build().parse("""
                  <project>
                      <parent>
                          <groupId>org.springframework.boot</groupId>
                          <artifactId>spring-boot-starter-parent</artifactId>
                          <version>3.2.0</version>
                          <relativePath/>
                      </parent>
                      <groupId>com.example</groupId>
                      <artifactId>demo</artifactId>
                      <version>0.0.1-SNAPSHOT</version>
                      <name>demo</name>
                      <dependencies>
                          <dependency>
                              <groupId>org.springframework.boot</groupId>
                              <artifactId>spring-boot-starter-web</artifactId>
                          </dependency>
                      </dependencies>
                  </project>
        """).toList().get(0);
        MavenResolutionResult resolutionResult = doc.getMarkers().findFirst(MavenResolutionResult.class).orElseThrow();
        resolutionResult = resolutionResult.resolveDependencies(new MavenPomDownloader(Collections.emptyMap(), new InMemoryExecutionContext(), null, null), new InMemoryExecutionContext());
        List<ResolvedDependency> deps = resolutionResult.getDependencies().get(Scope.Compile);
        assertThat(deps).hasSize(34);
    }

With version 8.42.0 and above the number of dependencies is 0. It is 0 because of this (change)[https://github.com//pull/4738/files#diff-80e53987f9ebb9e28874fed7053378def4769cef75b303770ccc8ee085fac098]

What happens is that for local maven repo if the JAR is around we wouldn't attempt to download the POM using another maven repo. I'm not sure how to correct this yet... probably if we've tried all repos and find a JAR for one of them then we can probably return the artificial POM based on the GAV only...

[BoykoAlex]

I've attached the PR but perhaps it is best to revert the change that caused the regression... If we are downloading the POM and failed to so why not throw exception regardless of the JAR presence?

[BoykoAlex]

@MBoegers and @sambsnyd could you please have a look at this issue? :-)