Get rid of maven-compat use Resolver API

animal-sniffer-maven-plugin/pom.xml

@@ -66,12 +66,6 @@
       <version>${maven.version}</version>
       <scope>provided</scope>
     </dependency>
-    <dependency>
-      <groupId>org.apache.maven</groupId>
-      <artifactId>maven-compat</artifactId>
-      <version>${maven.version}</version>
-      <scope>provided</scope>
-    </dependency>
     <dependency>
       <groupId>org.apache.maven</groupId>
       <artifactId>maven-artifact</artifactId>

animal-sniffer-maven-plugin/src/it/issue-24/verify.groovy

@@ -1,3 +1,3 @@
 File log = new File(basedir, 'build.log')
 assert log.exists()
-assert log.text.contains( 'For artifact {org.codehaus.mojo.signature:java14:null:signature}: The version cannot be empty.' )
+assert log.text.contains( 'For artifact {org.codehaus.mojo.signature:java14:signature:}: The version cannot be empty' )

animal-sniffer-maven-plugin/src/main/java/org/codehaus/mojo/animal_sniffer/maven/CheckSignatureMojo.java

@@ -26,10 +26,6 @@
  */
 
 import org.apache.maven.artifact.Artifact;
-import org.apache.maven.artifact.factory.ArtifactFactory;
-import org.apache.maven.artifact.repository.ArtifactRepository;
-import org.apache.maven.artifact.resolver.AbstractArtifactResolutionException;
-import org.apache.maven.artifact.resolver.ArtifactResolver;
 import org.apache.maven.model.Dependency;
 import org.apache.maven.plugin.AbstractMojo;
 import org.apache.maven.plugin.MojoExecutionException;
@@ -47,11 +43,15 @@
 import org.codehaus.mojo.animal_sniffer.Clazz;
 import org.codehaus.mojo.animal_sniffer.SignatureChecker;
 import org.codehaus.plexus.util.StringUtils;
+import org.eclipse.aether.RepositorySystem;
+import org.eclipse.aether.RepositorySystemSession;
+import org.eclipse.aether.resolution.ArtifactRequest;
+import org.eclipse.aether.resolution.ArtifactResolutionException;
+import org.eclipse.aether.resolution.ArtifactResult;
 
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
-import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
@@ -187,25 +187,16 @@ public void setSignature( String signatureId ) {
     @Parameter( defaultValue = "true", property = "animal.sniffer.failOnError" )
     protected boolean failOnError;
 
-    /**
-     */
-    @Component
-    protected ArtifactResolver resolver;
-
     /**
      */
     @Parameter( defaultValue = "${project}", readonly = true )
     protected MavenProject project;
 
-    /**
-     */
-    @Parameter( defaultValue = "${localRepository}", readonly=true )
-    protected ArtifactRepository localRepository;
+    @Parameter( defaultValue = "${repositorySystemSession}", readonly = true )
+    private RepositorySystemSession repositorySystemSession;
 
-    /**
-     */
     @Component
-    protected ArtifactFactory artifactFactory;
+    private RepositorySystem repositorySystem;
 
     static Map<File, Map<String, Clazz>> classes = new ConcurrentHashMap<>();
 
@@ -249,9 +240,8 @@ public void execute()
 
             getLog().info( "Checking unresolved references to " + signature );
 
-            Artifact a = signature.createArtifact( artifactFactory );
+            File signatureFile = resolveFileForArtifact( signature.createArtifact() );
 
-            resolver.resolve( a, project.getRemoteArtifactRepositories(), localRepository );
             // just check code from this module
             final Set<String> ignoredPackages = buildPackageList();
 
@@ -268,7 +258,7 @@ public void execute()
             }
 
             final SignatureChecker signatureChecker =
-                new SignatureChecker( loadClasses( a.getFile() ), ignoredPackages,
+                new SignatureChecker( loadClasses( signatureFile ), ignoredPackages,
                                       new MavenLogger( getLog() ) );
             signatureChecker.setCheckJars( false ); // don't want to decend into jar files that have been copied to
                                                     // the output directory as resources.
@@ -309,12 +299,24 @@ public void execute()
         {
             throw new MojoExecutionException( "Failed to check signatures", e );
         }
-        catch ( AbstractArtifactResolutionException e )
+        catch ( ArtifactResolutionException e )
         {
             throw new MojoExecutionException( "Failed to obtain signature: " + signature, e );
         }
     }
 
+    private File resolveFileForArtifact(org.eclipse.aether.artifact.Artifact artifact )
+            throws ArtifactResolutionException, MojoExecutionException {
+
+        if ( StringUtils.isBlank( artifact.getVersion() ) ) {
+            throw new MojoExecutionException( "For artifact {" + artifact + "}: The version cannot be empty." );
+        }
+
+        ArtifactRequest request = new ArtifactRequest( artifact, project.getRemotePluginRepositories(), null );
+        ArtifactResult result = repositorySystem.resolveArtifact( repositorySystemSession, request );
+        return result.getArtifact().getFile();
+    }
+
     private static Map<String, Clazz> loadClasses( File f ) throws IOException
     {
         Map<String, Clazz> classes = CheckSignatureMojo.classes.get( f );

animal-sniffer-maven-plugin/src/main/java/org/codehaus/mojo/animal_sniffer/maven/Signature.java

@@ -25,8 +25,8 @@
  *
  */
 
-import org.apache.maven.artifact.Artifact;
-import org.apache.maven.artifact.factory.ArtifactFactory;
+import org.eclipse.aether.artifact.Artifact;
+import org.eclipse.aether.artifact.DefaultArtifact;
 
 /**
  * Represents artifact in Maven POM.
@@ -72,9 +72,9 @@ public void setVersion( String version )
         this.version = version;
     }
 
-    public Artifact createArtifact( ArtifactFactory factory )
+    public Artifact createArtifact()
     {
-        return factory.createArtifact( groupId, artifactId, version, null, "signature" );
+        return new DefaultArtifact( groupId, artifactId, "signature", version);
     }
 
     public String toString()