[
https://issues.apache.org/jira/browse/MNG-6732?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Tomo Suzuki updated MNG-6732:
-----------------------------
Description:
h1. Problem
Sometimes [Linkage Checker enforcer
rule|https://github.com/GoogleCloudPlatform/cloud-opensource-java/tree/master/enforcer-rules]
does not receive resolved artifact list because of a missing artifact even
when the missing artifact is unused after Maven's dependency mediation.
h1. Background
The enforcer rule fails to retrieve artifact list through
{{DefaultProjectDependenciesResolver.resolve}} when applied to
[grpc-java-by-example/chat-example/chat-vaadin-client|https://github.com/saturnism/grpc-java-by-example/tree/master/chat-example/chat-vaadin-client]
because of the missing {{xerces:xerces-impl:2.6.2}}, even though the artifact
does not appear in the final dependency graph. The artifact does not appear in
the graph because of Maven's dependency mediation.
Artifact xerces:xerces-impl:2.6.2 is not published in Maven Central.
In contrast, the enforcer rule can retrieve artifact list when applied to
[https://github.com/suztomo/spring-cloud-gcp/tree/v1.1.2-linkage-checker]
project even though it outputs "[WARNING] The POM for
xerces:xerces-impl:jar:2.6.2 is missing, no dependency information available".
The missing artifact does not appear in final dependency graph.
[https://github.com/GoogleCloudPlatform/cloud-opensource-java/issues/834]
h1. Diagnosis
Currently {{DefaultArtifactDescriptorReader.loadPom}} method checks
"ArtifactDescriptorPolicy.IGNORE_MISSING" policy upon
ArtifactNotFoundException. This allows
{{DefaultProjectDependenciesResolver.resolve}} calls
{{repoSystem.resolveDependencies}} to obtain partially resolved artifact list,
rather than failing entirely, when there is a missing artifact (such as
{{xerces:xerces-impl:2.6.2}})
However, when a retired Maven repository is involved (such as
[http://repository.codehaus.org/] ),
{{DefaultArtifactDescriptorReader.loadPom}} gets an ArtifactTransferException
and throws ArtifactDescriptorException without checking
"ArtifactDescriptorPolicy.IGNORE_MISSING" policy (excerpt below), and thus
{{DefaultProjectDependenciesResolver.resolve}} does not return partially
resolved artifact list.
{code:java}
catch ( ArtifactResolutionException e )
{
if ( e.getCause() instanceof ArtifactNotFoundException )
{
missingDescriptor( session, trace, a, (Exception)
e.getCause() );
if ( ( getPolicy( session, a, request ) &
ArtifactDescriptorPolicy.IGNORE_MISSING ) != 0 )
{
return null;
}
}
result.addException( e );
throw new ArtifactDescriptorException( result );
}
{code}
from
[DefaultArtifactDescriptorReader.java|https://github.com/apache/maven/blob/d3ace78/maven-resolver-provider/src/main/java/org/apache/maven/repository/internal/DefaultArtifactDescriptorReader.java#L255]
ArtifactNotFoundException is a special case of
[ArtifactTransferException|https://maven.apache.org/resolver/apidocs/org/eclipse/aether/transfer/ArtifactTransferException.html].
h1. Example Project
Example project to demonstrate the diagnosis:
[https://github.com/suztomo/maven-missing-artifact] . In this example, even
though module-b and module-c have the same dependency section, module-c fails
to run Maven because of a repository section containing a retired repository
URL.
was:
h1. Problem
Sometimes my Maven enforcer rule does not receive resolved artifact list
because of missing artifact even when the missing artifact does not appear in
the final dependency graph.
h1. Background
Artifact xerces:xerces-impl:2.6.2 is not published in Maven Central.
My enforcer rule can retrieve artifact list through
DefaultProjectDependenciesResolver.resolve when applied to
[https://github.com/suztomo/spring-cloud-gcp/tree/v1.1.2-linkage-checker]
project even though it outputs "[WARNING] The POM for
xerces:xerces-impl:jar:2.6.2 is missing, no dependency information available".
The missing artifact does not appear in final dependency graph.
On the other hand, the enforcer rule fails to retrieve artifact list when
applied to
[grpc-java-by-example/chat-example/chat-vaadin-client|https://github.com/saturnism/grpc-java-by-example/tree/master/chat-example/chat-vaadin-client]
because of the missing xerces:xerces-impl:2.6.2, even though the artifact
should not appear in the final dependency graph.
[https://github.com/GoogleCloudPlatform/cloud-opensource-java/issues/834]
h1. Diagnosis
Currently DefaultArtifactDescriptorReader.loadPom method checks
"ArtifactDescriptorPolicy.IGNORE_MISSING" policy upon
ArtifactNotFoundException. This allows
DefaultProjectDependenciesResolver.resolve calls repoSystem.resolveDependencies
to obtain partially resolved artifact list even when there is a missing
artifact (such as xerces:xerces-impl:2.6.2)
However, when there is a retired Maven repository is involved (such as
[http://repository.codehaus.org/] ), DefaultArtifactDescriptorReader.loadPom
method gets an ArtifactTransferException and throws ArtifactDescriptorException
without checking "ArtifactDescriptorPolicy.IGNORE_MISSING" policy (excerpt
below), and thus DefaultProjectDependenciesResolver.resolve does not return
partially resolved artifact list.
{code:java}
catch ( ArtifactResolutionException e )
{
if ( e.getCause() instanceof ArtifactNotFoundException )
{
missingDescriptor( session, trace, a, (Exception)
e.getCause() );
if ( ( getPolicy( session, a, request ) &
ArtifactDescriptorPolicy.IGNORE_MISSING ) != 0 )
{
return null;
}
}
result.addException( e );
throw new ArtifactDescriptorException( result );
}
{code}
from
[DefaultArtifactDescriptorReader.java|https://github.com/apache/maven/blob/d3ace78/maven-resolver-provider/src/main/java/org/apache/maven/repository/internal/DefaultArtifactDescriptorReader.java#L255]
ArtifactNotFoundException is a special case of
[ArtifactTransferException|https://maven.apache.org/resolver/apidocs/org/eclipse/aether/transfer/ArtifactTransferException.html].
h1. Example Project
Example project to demonstrate the diagnosis:
[https://github.com/suztomo/maven-missing-artifact] . In this example, even
though module-b and module-c have the same dependency section, module-c fails
to run Maven because of a repository section containing a retired repository
URL.
> DefaultArtifactDescriptorReader.loadPom to check IGNORE_MISSING policy upon
> ArtifactTransferException
> -----------------------------------------------------------------------------------------------------
>
> Key: MNG-6732
> URL: https://issues.apache.org/jira/browse/MNG-6732
> Project: Maven
> Issue Type: Improvement
> Components: core
> Affects Versions: 3.6.1
> Reporter: Tomo Suzuki
> Priority: Major
> Attachments: 62884438-89260580-bd04-11e9-8c4a-897d4b736dc7.png
>
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> h1. Problem
> Sometimes [Linkage Checker enforcer
> rule|https://github.com/GoogleCloudPlatform/cloud-opensource-java/tree/master/enforcer-rules]
> does not receive resolved artifact list because of a missing artifact even
> when the missing artifact is unused after Maven's dependency mediation.
> h1. Background
> The enforcer rule fails to retrieve artifact list through
> {{DefaultProjectDependenciesResolver.resolve}} when applied to
> [grpc-java-by-example/chat-example/chat-vaadin-client|https://github.com/saturnism/grpc-java-by-example/tree/master/chat-example/chat-vaadin-client]
> because of the missing {{xerces:xerces-impl:2.6.2}}, even though the
> artifact does not appear in the final dependency graph. The artifact does not
> appear in the graph because of Maven's dependency mediation.
> Artifact xerces:xerces-impl:2.6.2 is not published in Maven Central.
> In contrast, the enforcer rule can retrieve artifact list when applied to
> [https://github.com/suztomo/spring-cloud-gcp/tree/v1.1.2-linkage-checker]
> project even though it outputs "[WARNING] The POM for
> xerces:xerces-impl:jar:2.6.2 is missing, no dependency information
> available". The missing artifact does not appear in final dependency graph.
> [https://github.com/GoogleCloudPlatform/cloud-opensource-java/issues/834]
> h1. Diagnosis
> Currently {{DefaultArtifactDescriptorReader.loadPom}} method checks
> "ArtifactDescriptorPolicy.IGNORE_MISSING" policy upon
> ArtifactNotFoundException. This allows
> {{DefaultProjectDependenciesResolver.resolve}} calls
> {{repoSystem.resolveDependencies}} to obtain partially resolved artifact
> list, rather than failing entirely, when there is a missing artifact (such as
> {{xerces:xerces-impl:2.6.2}})
> However, when a retired Maven repository is involved (such as
> [http://repository.codehaus.org/] ),
> {{DefaultArtifactDescriptorReader.loadPom}} gets an ArtifactTransferException
> and throws ArtifactDescriptorException without checking
> "ArtifactDescriptorPolicy.IGNORE_MISSING" policy (excerpt below), and thus
> {{DefaultProjectDependenciesResolver.resolve}} does not return partially
> resolved artifact list.
> {code:java}
> catch ( ArtifactResolutionException e )
> {
> if ( e.getCause() instanceof ArtifactNotFoundException )
> {
> missingDescriptor( session, trace, a, (Exception)
> e.getCause() );
> if ( ( getPolicy( session, a, request ) &
> ArtifactDescriptorPolicy.IGNORE_MISSING ) != 0 )
> {
> return null;
> }
> }
> result.addException( e );
> throw new ArtifactDescriptorException( result );
> }
> {code}
> from
> [DefaultArtifactDescriptorReader.java|https://github.com/apache/maven/blob/d3ace78/maven-resolver-provider/src/main/java/org/apache/maven/repository/internal/DefaultArtifactDescriptorReader.java#L255]
> ArtifactNotFoundException is a special case of
> [ArtifactTransferException|https://maven.apache.org/resolver/apidocs/org/eclipse/aether/transfer/ArtifactTransferException.html].
> h1. Example Project
> Example project to demonstrate the diagnosis:
> [https://github.com/suztomo/maven-missing-artifact] . In this example, even
> though module-b and module-c have the same dependency section, module-c fails
> to run Maven because of a repository section containing a retired repository
> URL.
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