[MRESOLVER-338] Drop FileTransform API (#337)

To streamline logic all way down to transport and remove OOM prone code.

Note: japicmp config was added, as we did a mistake, we deprecated types, but not related methods, so without these japicm would fail the build due breakages.

---

https://issues.apache.org/jira/browse/MRESOLVER-338

maven-resolver-api/src/main/java/org/eclipse/aether/AbstractForwardingRepositorySystemSession.java

@@ -35,7 +35,6 @@
 import org.eclipse.aether.resolution.ArtifactDescriptorPolicy;
 import org.eclipse.aether.resolution.ResolutionErrorPolicy;
 import org.eclipse.aether.transfer.TransferListener;
-import org.eclipse.aether.transform.FileTransformerManager;
 
 /**
  * A special repository system session to enable decorating or proxying another session. To do so, clients have to
@@ -186,9 +185,4 @@ public SessionData getData() {
     public RepositoryCache getCache() {
         return getSession().getCache();
     }
-
-    @Override
-    public FileTransformerManager getFileTransformerManager() {
-        return getSession().getFileTransformerManager();
-    }
 }

maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositorySystemSession.java

@@ -18,12 +18,10 @@
  */
 package org.eclipse.aether;
 
-import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
-import org.eclipse.aether.artifact.Artifact;
 import org.eclipse.aether.artifact.ArtifactType;
 import org.eclipse.aether.artifact.ArtifactTypeRegistry;
 import org.eclipse.aether.collection.DependencyGraphTransformer;
@@ -44,8 +42,6 @@
 import org.eclipse.aether.resolution.ArtifactDescriptorPolicy;
 import org.eclipse.aether.resolution.ResolutionErrorPolicy;
 import org.eclipse.aether.transfer.TransferListener;
-import org.eclipse.aether.transform.FileTransformer;
-import org.eclipse.aether.transform.FileTransformerManager;
 
 import static java.util.Objects.requireNonNull;
 
@@ -77,8 +73,6 @@ public final class DefaultRepositorySystemSession implements RepositorySystemSes
 
     private LocalRepositoryManager localRepositoryManager;
 
-    private FileTransformerManager fileTransformerManager;
-
     private WorkspaceReader workspaceReader;
 
     private RepositoryListener repositoryListener;
@@ -135,7 +129,6 @@ public DefaultRepositorySystemSession() {
         proxySelector = NullProxySelector.INSTANCE;
         authenticationSelector = NullAuthenticationSelector.INSTANCE;
         artifactTypeRegistry = NullArtifactTypeRegistry.INSTANCE;
-        fileTransformerManager = NullFileTransformerManager.INSTANCE;
         data = new DefaultSessionData();
     }
 
@@ -173,7 +166,6 @@ public DefaultRepositorySystemSession(RepositorySystemSession session) {
         setDependencySelector(session.getDependencySelector());
         setVersionFilter(session.getVersionFilter());
         setDependencyGraphTransformer(session.getDependencyGraphTransformer());
-        setFileTransformerManager(session.getFileTransformerManager());
         setData(session.getData());
         setCache(session.getCache());
     }
@@ -341,20 +333,6 @@ public DefaultRepositorySystemSession setLocalRepositoryManager(LocalRepositoryM
         return this;
     }
 
-    @Override
-    public FileTransformerManager getFileTransformerManager() {
-        return fileTransformerManager;
-    }
-
-    public DefaultRepositorySystemSession setFileTransformerManager(FileTransformerManager fileTransformerManager) {
-        verifyStateForMutation();
-        this.fileTransformerManager = fileTransformerManager;
-        if (this.fileTransformerManager == null) {
-            this.fileTransformerManager = NullFileTransformerManager.INSTANCE;
-        }
-        return this;
-    }
-
     @Override
     public WorkspaceReader getWorkspaceReader() {
         return workspaceReader;
@@ -814,13 +792,4 @@ public ArtifactType get(String typeId) {
             return null;
         }
     }
-
-    static final class NullFileTransformerManager implements FileTransformerManager {
-        public static final FileTransformerManager INSTANCE = new NullFileTransformerManager();
-
-        @Override
-        public Collection<FileTransformer> getTransformersForArtifact(Artifact artifact) {
-            return Collections.emptyList();
-        }
-    }
 }

maven-resolver-api/src/main/java/org/eclipse/aether/RepositorySystemSession.java

@@ -36,7 +36,6 @@
 import org.eclipse.aether.resolution.ArtifactDescriptorPolicy;
 import org.eclipse.aether.resolution.ResolutionErrorPolicy;
 import org.eclipse.aether.transfer.TransferListener;
-import org.eclipse.aether.transform.FileTransformerManager;
 
 /**
  * Defines settings and components that control the repository system. Once initialized, the session object itself is
@@ -270,14 +269,4 @@ public interface RepositorySystemSession {
      * @return The repository cache or {@code null} if none.
      */
     RepositoryCache getCache();
-
-    /**
-     * Get the file transformer manager
-     *
-     * @return the manager, never {@code null}
-     * @deprecated Without any direct replacement for now. This API is OOM-prone, and also lacks a lot of context about
-     * transforming.
-     */
-    @Deprecated
-    FileTransformerManager getFileTransformerManager();
 }

maven-resolver-connector-basic/src/main/java/org/eclipse/aether/connector/basic/BasicRepositoryConnector.java

@@ -18,10 +18,8 @@
  */
 package org.eclipse.aether.connector.basic;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
-import java.io.InputStream;
 import java.io.UncheckedIOException;
 import java.net.URI;
 import java.util.ArrayList;
@@ -61,7 +59,6 @@
 import org.eclipse.aether.transfer.NoTransporterException;
 import org.eclipse.aether.transfer.TransferEvent;
 import org.eclipse.aether.transfer.TransferResource;
-import org.eclipse.aether.transform.FileTransformer;
 import org.eclipse.aether.util.ConfigUtils;
 import org.eclipse.aether.util.FileUtils;
 import org.eclipse.aether.util.concurrency.ExecutorUtils;
@@ -291,8 +288,7 @@ public void put(
             List<RepositoryLayout.ChecksumLocation> checksumLocations =
                     layout.getChecksumLocations(transfer.getArtifact(), true, location);
 
-            Runnable task = new PutTaskRunner(
-                    location, transfer.getFile(), transfer.getFileTransformer(), checksumLocations, listener);
+            Runnable task = new PutTaskRunner(location, transfer.getFile(), checksumLocations, listener);
             if (first) {
                 task.run();
                 first = false;
@@ -509,61 +505,23 @@ class PutTaskRunner extends TaskRunner {
 
         private final File file;
 
-        private final FileTransformer fileTransformer;
-
         private final Collection<RepositoryLayout.ChecksumLocation> checksumLocations;
 
         PutTaskRunner(
                 URI path,
                 File file,
                 List<RepositoryLayout.ChecksumLocation> checksumLocations,
                 TransferTransportListener<?> listener) {
-            this(path, file, null, checksumLocations, listener);
-        }
-
-        /**
-         * <strong>IMPORTANT</strong> When using a fileTransformer, the content of the file is stored in memory to
-         * ensure that file content and checksums stay in sync!
-         *
-         * @param path
-         * @param file
-         * @param fileTransformer
-         * @param checksumLocations
-         * @param listener
-         */
-        PutTaskRunner(
-                URI path,
-                File file,
-                FileTransformer fileTransformer,
-                List<RepositoryLayout.ChecksumLocation> checksumLocations,
-                TransferTransportListener<?> listener) {
             super(path, listener);
             this.file = requireNonNull(file, "source file cannot be null");
-            this.fileTransformer = fileTransformer;
             this.checksumLocations = safe(checksumLocations);
         }
 
         @SuppressWarnings("checkstyle:innerassignment")
         @Override
         protected void runTask() throws Exception {
-            if (fileTransformer != null) {
-                // transform data once to byte array, ensure constant data for checksum
-                ByteArrayOutputStream baos = new ByteArrayOutputStream();
-                byte[] buffer = new byte[1024];
-
-                try (InputStream transformData = fileTransformer.transformData(file)) {
-                    for (int read; (read = transformData.read(buffer, 0, buffer.length)) != -1; ) {
-                        baos.write(buffer, 0, read);
-                    }
-                }
-
-                byte[] bytes = baos.toByteArray();
-                transporter.put(new PutTask(path).setDataBytes(bytes).setListener(listener));
-                uploadChecksums(file, bytes);
-            } else {
-                transporter.put(new PutTask(path).setDataFile(file).setListener(listener));
-                uploadChecksums(file, null);
-            }
+            transporter.put(new PutTask(path).setDataFile(file).setListener(listener));
+            uploadChecksums(file, null);
         }
 
         /**