[fix] Merge comments attached to the compilation unit

src/main/java/se/kth/spork/cli/Cli.java

@@ -56,8 +56,13 @@ public static String prettyPrint(CtModule spoonRoot) {
                 .collect(Collectors.toList());
         new PrinterPreprocessor(importNames, activePackage.getQualifiedName()).scan(spoonRoot);
 
-
         StringBuilder sb = new StringBuilder();
+
+        String cuComment = (String) spoonRoot.getMetadata(Parser.COMPILATION_UNIT_COMMENT);
+        if (!cuComment.isEmpty()) {
+            sb.append(cuComment).append("\n");
+        }
+
         if (!activePackage.isUnnamedPackage()) {
             sb.append("package ").append(activePackage.getQualifiedName()).append(";").append("\n\n");
         }

src/main/java/se/kth/spork/spoon/Parser.java

@@ -7,6 +7,7 @@
 import spoon.Launcher;
 import spoon.compiler.Environment;
 import spoon.reflect.CtModel;
+import spoon.reflect.code.CtComment;
 import spoon.reflect.declaration.*;
 import spoon.support.compiler.FileSystemFile;
 import spoon.support.compiler.VirtualFile;
@@ -24,6 +25,7 @@
  */
 public class Parser {
     public static final String IMPORT_STATEMENTS = "spork_import_statements";
+    public static final String COMPILATION_UNIT_COMMENT = "spork_cu_comment";
 
     private static final LazyLogger LOGGER = new LazyLogger(Parser.class);
 
@@ -87,6 +89,11 @@ private static CtModule parse(Consumer<Launcher> addResource) {
 
         CtModule module = model.getUnnamedModule();
 
+        // FIXME This is an ugly workaround for merging compliation unit comments
+        List<CtComment> cuComments = module.getFactory().CompilationUnit().getMap().values().iterator().next().getComments();
+        String cuComment = cuComments.isEmpty() ? "" : cuComments.get(0).getRawContent();
+        module.putMetadata(COMPILATION_UNIT_COMMENT, cuComment);
+
         // TODO preserve order of import statements
         List<CtImport> imports = new ArrayList<>(parseImportStatements(model));
         imports.sort(Comparator.comparing(CtElement::prettyprint));

src/main/java/se/kth/spork/spoon/Spoon3dmMerge.java

@@ -12,6 +12,7 @@
 import se.kth.spork.spoon.wrappers.RoledValues;
 import se.kth.spork.spoon.wrappers.SpoonNode;
 import se.kth.spork.util.LazyLogger;
+import se.kth.spork.util.LineBasedMerge;
 import se.kth.spork.util.Pair;
 import spoon.reflect.declaration.*;
 
@@ -129,9 +130,31 @@ public static <T extends CtElement> Pair<T, Integer> merge(T base, T left, T rig
         List<CtImport> mergedImports = mergeImportStatements(base, left, right);
         mergeTree.putMetadata(Parser.IMPORT_STATEMENTS, mergedImports);
 
+        LOGGER.info(() -> "Merging compilation unit comments");
+        Pair<String, Integer> cuCommentMerge = mergeCuComments(base, left, right);
+        int cuCommentConflicts = cuCommentMerge.second;
+        mergeTree.putMetadata(Parser.COMPILATION_UNIT_COMMENT, cuCommentMerge.first);
+
         LOGGER.info(() -> "Merged in " + (double) (System.nanoTime() - start) / 1e9 + " seconds");
 
-        return Pair.of(mergeTree, numConflicts);
+        return Pair.of(mergeTree, numConflicts + cuCommentConflicts);
+    }
+
+    /**
+     * Perform a line-based merge of the compilation unit comments.
+     *
+     * @return A pair with the merge and the amount of conflicts.
+     */
+    private static Pair<String, Integer> mergeCuComments(CtElement base, CtElement left, CtElement right) {
+        String baseComment = getCuComment(base);
+        String leftComment = getCuComment(left);
+        String rightComment = getCuComment(right);
+        return LineBasedMerge.merge(baseComment, leftComment, rightComment);
+    }
+
+    private static String getCuComment(CtElement mod) {
+        String comment = (String) mod.getMetadata(Parser.COMPILATION_UNIT_COMMENT);
+        return comment == null ? "" : comment;
     }
 
     /**

src/test/java/se/kth/spork/spoon/Spoon3dmMergeTest.java

@@ -52,19 +52,24 @@ void merge_shouldThrow_onUnhandledInconsistencies(Util.TestSources sources) {
     private static void runTestMerge(Util.TestSources sources) {
         CtModule expected = Parser.parse(sources.expected);
         Object expectedImports = expected.getMetadata(Parser.IMPORT_STATEMENTS);
+        Object expectedCuComment = expected.getMetadata(Parser.COMPILATION_UNIT_COMMENT);
         assert expectedImports != null;
+        assert expectedCuComment != null;
 
         Pair<CtModule, Integer> merged = Spoon3dmMerge.merge(sources.base, sources.left, sources.right);
         CtModule mergeTree = merged.first;
         Object mergedImports = mergeTree.getMetadata(Parser.IMPORT_STATEMENTS);
+        Object mergedCuComment = mergeTree.getMetadata(Parser.COMPILATION_UNIT_COMMENT);
 
         // this assert is just to give a better overview of obvious errors, but it relies on the pretty printer's
         // correctness
         // assertEquals(Cli.prettyPrint(expected), Cli.prettyPrint(mergeTree));
+        System.out.println(Cli.prettyPrint(mergeTree));
 
         // these asserts are what actually matters
         assertEquals(expected, mergeTree);
         assertEquals(expectedImports, mergedImports);
+        assertEquals(expectedCuComment, mergedCuComment);
     }
 }