Improve artifact comparison delta results

tycho-artifactcomparator/src/main/java/org/eclipse/tycho/artifactcomparator/ArtifactDelta.java

@@ -12,6 +12,9 @@
  *******************************************************************************/
 package org.eclipse.tycho.artifactcomparator;
 
+import java.io.File;
+import java.io.IOException;
+
 import org.eclipse.tycho.zipcomparator.internal.SimpleArtifactDelta;
 
 /**
@@ -49,4 +52,12 @@ public interface ArtifactDelta {
      */
     public String getDetailedMessage();
 
+    /**
+     * Writes some details about this delta to the given destination
+     * 
+     * @param destination
+     * @throws IOException
+     */
+    void writeDetails(File destination) throws IOException;
+
 }

tycho-artifactcomparator/src/main/java/org/eclipse/tycho/zipcomparator/internal/ClassfileComparator.java

@@ -12,6 +12,7 @@
  *******************************************************************************/
 package org.eclipse.tycho.zipcomparator.internal;
 
+import java.io.File;
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.io.StringWriter;
@@ -47,7 +48,7 @@ public ArtifactDelta getDelta(ComparatorInputStream baseline, ComparatorInputStr
             if (baselineDisassemble.equals(reactorDisassemble)) {
                 return ArtifactDelta.NO_DIFFERENCE;
             }
-            return new SimpleArtifactDelta("different", baselineDisassemble, reactorDisassemble);
+            return new ClassfileArtifactDelta(baselineDisassemble, reactorDisassemble, baseline, reactor);
         } catch (RuntimeException e) {
             return baseline.compare(reactor);
         }
@@ -79,4 +80,26 @@ private String disassemble(byte[] bytes) {
     public boolean matches(String extension) {
         return TYPE.equalsIgnoreCase(extension);
     }
+
+    private static final class ClassfileArtifactDelta extends SimpleArtifactDelta {
+
+        private ComparatorInputStream baselineStream;
+        private ComparatorInputStream reactorStream;
+
+        public ClassfileArtifactDelta(String baseline, String reactor, ComparatorInputStream baselineStream,
+                ComparatorInputStream reactorStream) {
+            super("different", baseline, reactor);
+            this.baselineStream = baselineStream;
+            this.reactorStream = reactorStream;
+        }
+
+        @Override
+        public void writeDetails(File destination) throws IOException {
+            super.writeDetails(destination);
+            File basedir = destination.getParentFile();
+            writeFile(basedir, destination.getName() + "-baseline.class", baselineStream);
+            writeFile(basedir, destination.getName() + "-build.class", reactorStream);
+        }
+
+    }
 }

tycho-artifactcomparator/src/main/java/org/eclipse/tycho/zipcomparator/internal/CompoundArtifactDelta.java

@@ -14,7 +14,6 @@
 
 import java.io.File;
 import java.io.IOException;
-import java.nio.file.Files;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -62,26 +61,12 @@ private void indent(StringBuilder message, int indent) {
         }
     }
 
+    @Override
     public void writeDetails(File basedir) throws IOException {
         for (Map.Entry<String, ArtifactDelta> member : members.entrySet()) {
             ArtifactDelta memberDelta = member.getValue();
-            if (memberDelta instanceof CompoundArtifactDelta compoundDelta) {
-                compoundDelta.writeDetails(new File(basedir, member.getKey()));
-            } else if (memberDelta instanceof SimpleArtifactDelta delta) {
-                if (delta.getBaseline() != null) {
-                    writeFile(basedir, member.getKey() + "-baseline", delta.getBaseline());
-                }
-                if (delta.getReactor() != null) {
-                    writeFile(basedir, member.getKey() + "-build", delta.getReactor());
-                }
-            }
+            memberDelta.writeDetails(new File(basedir, member.getKey()));
         }
     }
 
-    private void writeFile(File basedir, String path, String data) throws IOException {
-        File file = new File(basedir, path).getAbsoluteFile();
-        file.getParentFile().mkdirs();
-        Files.writeString(file.toPath(), data);
-    }
-
 }

tycho-artifactcomparator/src/main/java/org/eclipse/tycho/zipcomparator/internal/SimpleArtifactDelta.java

@@ -12,6 +12,11 @@
  *******************************************************************************/
 package org.eclipse.tycho.zipcomparator.internal;
 
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+
 import org.eclipse.tycho.artifactcomparator.ArtifactDelta;
 
 public class SimpleArtifactDelta implements ArtifactDelta {
@@ -56,4 +61,26 @@ public String getBaseline() {
     public String getReactor() {
         return reactor;
     }
+
+    @Override
+    public void writeDetails(File destination) throws IOException {
+        if (getBaseline() != null) {
+            writeFile(destination.getParentFile(), destination.getName() + "-baseline", getBaseline());
+        }
+        if (getReactor() != null) {
+            writeFile(destination.getParentFile(), destination.getName() + "-build", getReactor());
+        }
+    }
+
+    protected static void writeFile(File basedir, String path, String data) throws IOException {
+        File file = new File(basedir, path).getAbsoluteFile();
+        file.getParentFile().mkdirs();
+        Files.writeString(file.toPath(), data);
+    }
+
+    protected static void writeFile(File basedir, String path, InputStream data) throws IOException {
+        File file = new File(basedir, path).getAbsoluteFile();
+        file.getParentFile().mkdirs();
+        Files.copy(data, file.toPath());
+    }
 }

tycho-artifactcomparator/src/main/java/org/eclipse/tycho/zipcomparator/internal/ZipComparatorImpl.java

@@ -16,6 +16,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.file.Files;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashSet;
@@ -82,7 +83,27 @@ public ArtifactDelta getDelta(File baseline, File reactor, ComparisonData data)
             }
             return ArtifactDelta.DEFAULT;
         }
-        return !result.isEmpty() ? new CompoundArtifactDelta("different", result) : null;
+        return !result.isEmpty() ? new ZipArtifactDelta(result, baseline, reactor) : null;
+    }
+
+    private static final class ZipArtifactDelta extends CompoundArtifactDelta {
+
+        private File baseline;
+        private File reactor;
+
+        public ZipArtifactDelta(Map<String, ? extends ArtifactDelta> members, File baseline, File reactor) {
+            super("different", members);
+            this.baseline = baseline;
+            this.reactor = reactor;
+        }
+
+        @Override
+        public void writeDetails(File basedir) throws IOException {
+            super.writeDetails(basedir);
+            Files.copy(baseline.toPath(), basedir.toPath().resolve("baseline-" + baseline.getName()));
+            Files.copy(reactor.toPath(), basedir.toPath().resolve("build-" + reactor.getName()));
+        }
+
     }
 
     private ArtifactDelta getDelta(String name, Map<String, ZipEntry> baselineMap, Map<String, ZipEntry> reactorMap,

tycho-p2-plugin/src/main/java/org/eclipse/tycho/plugins/p2/BaselineValidator.java

@@ -60,6 +60,11 @@ public String getMessage() {
         public String getDetailedMessage() {
             return getMessage();
         }
+
+        @Override
+        public void writeDetails(File destination) throws IOException {
+
+        }
     }
 
     @Requirement
@@ -97,9 +102,7 @@ public Map<String, IP2Artifact> validateAndReplace(MavenProject project, Compari
                         File logdir = new File(project.getBuild().getDirectory(), "artifactcomparison");
                         log.info("Artifact comparison detailed log directory " + logdir.getAbsolutePath());
                         for (Map.Entry<String, ArtifactDelta> classifier : delta.getMembers().entrySet()) {
-                            if (classifier.getValue() instanceof CompoundArtifactDelta compoundDelta) {
-                                compoundDelta.writeDetails(new File(logdir, classifier.getKey()));
-                            }
+                            classifier.getValue().writeDetails(new File(logdir, classifier.getKey()));
                         }
                     }
                     if (baselineMode == fail || (baselineMode == failCommon && !isMissingOnlyDelta(delta))) {