WIP

pom.xml

@@ -74,7 +74,8 @@
         <dependency>
             <groupId>org.eclipse.jgit</groupId>
             <artifactId>org.eclipse.jgit</artifactId>
-            <version>6.3.0.202209071007-r</version>
+            <!-- <version>6.9.0.202403050737-r</version> -->
+            <version>6.10.0-SNAPSHOT</version>
         </dependency>
         <dependency>
             <groupId>org.jetbrains.kotlin</groupId>

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

@@ -57,7 +57,7 @@ public static String prettyPrint(CtModule spoonRoot) {
                         .map(Object::toString)
                         .map(impStmt -> impStmt.substring("import ".length(), impStmt.length() - 1))
                         .collect(Collectors.toList());
-        new PrinterPreprocessor(importNames, activePackage.getQualifiedName()).scan(spoonRoot);
+        new PrinterPreprocessor(importNames, activePackage.getQualifiedName(), Spoon3dmMerge.INSTANCE.getDiff3()).scan(spoonRoot);
 
         StringBuilder sb = new StringBuilder();
 
@@ -172,7 +172,7 @@ public Integer call() throws IOException {
                 rightPath.toFile().deleteOnExit();
             }
 
-            Pair<String, Integer> merged = merge(basePath, leftPath, rightPath, exitOnError);
+            Pair<String, Integer> merged = merge(basePath, leftPath, rightPath, exitOnError, diff3);
             String pretty = merged.getFirst();
             int numConflicts = merged.getSecond();
 
@@ -205,10 +205,11 @@ public Integer call() throws IOException {
      * @param right Path to right revision.
      * @param exitOnError Disallow the use of line-based fallback if the structured merge encounters
      *     an error.
+     * @param diff3 whether to use the diff3 style one or the default one
      * @return A pair on the form (prettyPrint, numConflicts)
      */
     public static Pair<String, Integer> merge(
-            Path base, Path left, Path right, boolean exitOnError) {
+            Path base, Path left, Path right, boolean exitOnError, boolean diff3) {
         try {
             LOGGER.info(() -> "Parsing input files");
             CtModule baseModule = Parser.INSTANCE.parse(base);
@@ -231,7 +232,7 @@ public static Pair<String, Integer> merge(
                 LOGGER.warn(
                         () ->
                                 "Merge contains no types (i.e. classes, interfaces, etc), reverting to line-based merge");
-                return lineBasedMerge(base, left, right);
+                return lineBasedMerge(base, left, right, diff3);
             }
         } catch (Exception e) {
             if (exitOnError) {
@@ -244,16 +245,16 @@ public static Pair<String, Integer> merge(
                 LOGGER.info(
                         () ->
                                 "Spork encountered an error in structured merge. Falling back to line-based merge");
-                return lineBasedMerge(base, left, right);
+                return lineBasedMerge(base, left, right, diff3);
             }
         }
     }
 
-    private static Pair<String, Integer> lineBasedMerge(Path base, Path left, Path right) {
+    private static Pair<String, Integer> lineBasedMerge(Path base, Path left, Path right, boolean diff3) {
         String baseStr = Parser.INSTANCE.read(base);
         String leftStr = Parser.INSTANCE.read(left);
         String rightStr = Parser.INSTANCE.read(right);
-        return LineBasedMergeKt.lineBasedMerge(baseStr, leftStr, rightStr);
+        return LineBasedMergeKt.lineBasedMerge(baseStr, leftStr, rightStr, diff3);
     }
 
     /**

src/main/java/se/kth/spork/spoon/printer/PrinterPreprocessor.java

@@ -33,6 +33,7 @@ public class PrinterPreprocessor extends CtScanner {
     private final String activePackage;
 
     private final Map<String, Set<CtPackageReference>> refToPack;
+    private final boolean diff3;
 
     private int currentConflictId;
 
@@ -41,12 +42,13 @@ public class PrinterPreprocessor extends CtScanner {
     // TODO improve the pretty-printer such that this hack is redundant
     private final Map<String, Triple<String, String, String>> globalContentConflicts;
 
-    public PrinterPreprocessor(List<String> importStatements, String activePackage) {
+    public PrinterPreprocessor(List<String> importStatements, String activePackage, boolean diff3) {
         this.importStatements = importStatements;
         this.activePackage = activePackage;
         refToPack = new HashMap<>();
         currentConflictId = 0;
         globalContentConflicts = new HashMap<>();
+        this.diff3 = diff3;
     }
 
     @Override
@@ -143,13 +145,13 @@ private void processConflict(ContentConflict conflict, CtElement element) {
                 String rawRight =
                         (String) conflict.getRight().getMetadata(RoledValue.Key.RAW_CONTENT);
                 String rawBase =
-                        conflict.getBase() == null
+                        conflict.getBase() != null
                                 ? (String)
                                         conflict.getBase().getMetadata(RoledValue.Key.RAW_CONTENT)
                                 : "";
 
                 Pair<String, Integer> rawConflict =
-                        LineBasedMergeKt.lineBasedMerge(rawBase, rawLeft, rawRight);
+                        LineBasedMergeKt.lineBasedMerge(rawBase, rawLeft, rawRight, diff3);
                 assert rawConflict.getSecond() > 0
                         : "Comments without conflict should already have been merged";
 

src/main/kotlin/se/kth/spork/spoon/Spoon3dmMerge.kt

@@ -318,7 +318,7 @@ object Spoon3dmMerge {
         val baseComment = getCuComment(base)
         val leftComment = getCuComment(left)
         val rightComment = getCuComment(right)
-        return lineBasedMerge(baseComment, leftComment, rightComment)
+        return lineBasedMerge(baseComment, leftComment, rightComment, diff3)
     }
 
     private fun getCuComment(mod: CtElement): String = mod.getMetadata(Parser.COMPILATION_UNIT_COMMENT) as String

src/main/kotlin/se/kth/spork/spoon/conflict/CommentContentHandler.kt

@@ -20,12 +20,13 @@ class CommentContentHandler : ContentConflictHandler {
         baseElem: CtElement?,
         leftElem: CtElement,
         rightElem: CtElement,
+        diff3: Boolean,
     ): Pair<Any?, Boolean> {
-        return Pair(mergeComments(baseVal ?: "", leftVal, rightVal), false)
+        return Pair(mergeComments(baseVal ?: "", leftVal, rightVal, diff3), false)
     }
 
-    private fun mergeComments(base: Any, left: Any, right: Any): Any? {
-        val merge = lineBasedMerge(base.toString(), left.toString(), right.toString())
+    private fun mergeComments(base: Any, left: Any, right: Any, diff3: Boolean): Any? {
+        val merge = lineBasedMerge(base.toString(), left.toString(), right.toString(), diff3)
         return if (merge.second > 0) {
             null
         } else {

src/main/kotlin/se/kth/spork/spoon/conflict/ContentConflictHandler.kt

@@ -39,6 +39,7 @@ interface ContentConflictHandler {
         baseElem: CtElement?,
         leftElem: CtElement,
         rightElem: CtElement,
+        diff3: Boolean,
     ): Pair<Any?, Boolean>
 
     /** @return The role that this conflict handler deals with.

src/main/kotlin/se/kth/spork/spoon/conflict/ContentMerger.kt

@@ -24,6 +24,7 @@ class ContentMerger(conflictHandlers: List<ContentConflictHandler>) {
      */
     fun mergedContent(
         nodeContents: Set<Content<SpoonNode, RoledValues>>,
+        diff3: Boolean,
     ): Pair<RoledValues?, List<ContentConflict>> {
         if (nodeContents.size == 1) {
             return Pair(nodeContents.iterator().next().value, emptyList())
@@ -85,6 +86,7 @@ class ContentMerger(conflictHandlers: List<ContentConflictHandler>) {
                         baseRoledValues?.element,
                         leftRoledValues.element,
                         rightRoledValues.element,
+                        diff3,
                     )
                     merged = result.first
                     conflictPresent = result.second

src/main/kotlin/se/kth/spork/spoon/conflict/IsImplicitHandler.kt

@@ -20,6 +20,7 @@ class IsImplicitHandler : ContentConflictHandler {
         baseElem: CtElement?,
         leftElem: CtElement,
         rightElem: CtElement,
+        diff3: Boolean,
     ): Pair<Any?, Boolean> {
         val mergedValue = if (baseVal != null) {
             // as there are only two possible values for a boolean, left and right disagreeing must

src/main/kotlin/se/kth/spork/spoon/conflict/IsUpperHandler.kt

@@ -22,6 +22,7 @@ class IsUpperHandler : ContentConflictHandler {
         baseElem: CtElement?,
         leftElem: CtElement,
         rightElem: CtElement,
+        diff3: Boolean,
     ): Pair<Any?, Boolean> {
         return Pair(mergeIsUpper(baseElem, leftElem, rightElem), false)
     }

src/main/kotlin/se/kth/spork/spoon/conflict/ModifierHandler.kt

@@ -25,6 +25,7 @@ class ModifierHandler : ContentConflictHandler {
         baseElem: CtElement?,
         leftElem: CtElement,
         rightElem: CtElement,
+        diff3: Boolean,
     ): Pair<Any?, Boolean> {
         return mergeModifierKinds(
             (baseVal ?: setOf<ModifierKind>()) as Set<ModifierKind>,

src/main/kotlin/se/kth/spork/spoon/pcsinterpreter/PcsInterpreter.kt

@@ -26,7 +26,7 @@ fun fromMergedPcs(
     contentConflictHandlers: List<ContentConflictHandler>,
     diff3: Boolean
 ): Pair<CtElement?, Int> {
-    val sporkTreeBuilder = SporkTreeBuilder(base, delta, baseLeft, baseRight, structuralConflictHandlers)
+    val sporkTreeBuilder = SporkTreeBuilder(base, delta, baseLeft, baseRight, structuralConflictHandlers, diff3)
     val sporkTreeRoot = sporkTreeBuilder.buildTree()
 
     // this is a bit of a hack, get any used environment such that the SpoonTreeBuilder can copy environment details

src/main/kotlin/se/kth/spork/spoon/pcsinterpreter/SpoonTreeBuilder.kt

@@ -116,7 +116,7 @@ class SpoonTreeBuilder internal constructor(
             mergeTree = originalTree.clone()
             mergeTree.putMetadata<CtElement>(SINGLE_REVISION_KEY, sporkChild.singleRevision)
         } else {
-            val mergedContent = contentMerger.mergedContent(sporkChild.content)
+            val mergedContent = contentMerger.mergedContent(sporkChild.content, diff3)
             mergeTree = shallowCopyTree(originalTree, factory)
             mergedContent
                 .first?.forEach { roledValue ->

src/main/kotlin/se/kth/spork/spoon/pcsinterpreter/SporkTreeBuilder.kt

@@ -36,6 +36,7 @@ internal class SporkTreeBuilder(
     private val baseLeft: SpoonMapping,
     private val baseRight: SpoonMapping,
     private val conflictHandlers: List<StructuralConflictHandler>,
+    private val diff3: Boolean
 ) {
     private val rootToChildren: Map<SpoonNode, Map<SpoonNode, Pcs<SpoonNode>>> = buildRootToChildren(delta.pcsSet)
     private val baseRootToChildren: Map<SpoonNode, Map<SpoonNode, Pcs<SpoonNode>>> = buildRootToChildren(base.pcsSet)
@@ -130,7 +131,7 @@ internal class SporkTreeBuilder(
     }
 
     private fun build(start: SpoonNode, tree: SporkTree, children: Map<SpoonNode, Pcs<SpoonNode>>?, baseChildren: Map<SpoonNode, Pcs<SpoonNode>>?) {
-        if (children == null || baseChildren == null) {
+        if (children == null) {
             // leaf node
             return
         }
@@ -209,6 +210,7 @@ internal class SporkTreeBuilder(
             base.element,
             left!!.element,
             right!!.element,
+            diff3
         )
         numStructuralConflicts += second
         return StructuralConflict(
@@ -224,7 +226,7 @@ internal class SporkTreeBuilder(
         conflicting: Pcs<SpoonNode>,
         baseSuccessor: Pcs<SpoonNode>?,
         children: Map<SpoonNode, Pcs<SpoonNode>>,
-        baseChildren: Map<SpoonNode, Pcs<SpoonNode>>,
+        baseChildren: Map<SpoonNode, Pcs<SpoonNode>>?,
         tree: SporkTree,
     ): SpoonNode {
         remainingInconsistencies.remove(nextPcs)

src/main/kotlin/se/kth/spork/util/LineBasedMerge.kt

@@ -19,7 +19,7 @@ import java.util.Objects
  * @param right The right revision.
  * @return A pair containing the merge and the amount of conflicts.
  */
-fun lineBasedMerge(base: String, left: String, right: String): Pair<String, Int> {
+fun lineBasedMerge(base: String, left: String, right: String, diff3: Boolean): Pair<String, Int> {
     if (base.isEmpty() && (left.isEmpty() || right.isEmpty())) {
         // For some reason, this merge implementation reports a conflict on pure additions.
         // This is an easy fix for that. See #144 for details.
@@ -31,6 +31,7 @@ fun lineBasedMerge(base: String, left: String, right: String): Pair<String, Int>
     val rightRaw = RawText(right.toByteArray())
 
     val merge = MergeAlgorithm()
+
     val res: MergeResult<RawText> = merge.merge(
         object : SequenceComparator<RawText>() {
             override fun equals(lhs: RawText, lhsIdx: Int, rhs: RawText, rhsIdx: Int) =
@@ -63,6 +64,16 @@ fun lineBasedMerge(base: String, left: String, right: String): Pair<String, Int>
                 inConflict = true
             }
             lines.add(SporkPrettyPrinter.MID_CONFLICT)
+        } else if (chunk.conflictState
+            == MergeChunk.ConflictState.BASE_CONFLICTING_RANGE) {
+            if (!diff3) {
+                continue;
+            }
+            if (!inConflict) {
+                lines.add(SporkPrettyPrinter.START_CONFLICT)
+                inConflict = true
+            }
+            lines.add(SporkPrettyPrinter.BASE_CONFLICT)
         }
         for (i in chunk.begin until chunk.end) {
             lines.add(seq.getString(i))
@@ -89,9 +100,9 @@ fun lineBasedMerge(base: String, left: String, right: String): Pair<String, Int>
  * @param right The right revision.
  * @return A pair containing the merge and the amount of conflicts.
  */
-fun lineBasedMerge(base: CtElement, left: CtElement, right: CtElement): Pair<String, Int> {
+fun lineBasedMerge(base: CtElement, left: CtElement, right: CtElement, diff3: Boolean): Pair<String, Int> {
     val baseSource = SourceExtractor.getOriginalSource(base)
     val leftSource = SourceExtractor.getOriginalSource(left)
     val rightSource = SourceExtractor.getOriginalSource(right)
-    return lineBasedMerge(baseSource, leftSource, rightSource)
+    return lineBasedMerge(baseSource, leftSource, rightSource, diff3)
 }

src/test/java/se/kth/spork/LineBasedMergeTest.java

@@ -0,0 +1,24 @@
+package se.kth.spork;
+
+import kotlin.Pair;
+import org.junit.jupiter.api.Test;
+import se.kth.spork.util.LineBasedMergeKt;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class LineBasedMergeTest {
+    @Test
+    public void testSimpleMerge() {
+        Pair<String, Integer> result = LineBasedMergeKt.lineBasedMerge("hello world", "ola mundo", "bonjour le monde", true);
+
+        assertEquals(result.component1(),
+                "<<<<<<< LEFT\n" +
+                "ola mundo\n" +
+                "||||||| BASE\n" +
+                "hello world\n" +
+                "=======\n" +
+                "bonjour le monde\n" +
+                ">>>>>>> RIGHT");
+        assertEquals(result.component2(), 1);
+    }
+}

src/test/java/se/kth/spork/cli/CliTest.java

@@ -53,7 +53,7 @@ void merge_shouldThrowOnMissingType_whenGlobalFallbackIsDisabled() {
 
         assertThrows(
                 MergeException.class,
-                () -> Cli.merge(sources.base, sources.left, sources.right, /* exitOnError= */ true),
+                () -> Cli.merge(sources.base, sources.left, sources.right, /* exitOnError= */ true, /* diff3 = */ false),
                 "Merge contained no types and global line-based fallback is disabled");
     }
 
@@ -64,7 +64,7 @@ void merge_shouldMexgeCorrectlyOnMissingType_whenGlobalFallbackIsEnabled() {
         String expected = Parser.INSTANCE.read(sources.expected);
 
         Pair<String, Integer> merge =
-                Cli.merge(sources.base, sources.left, sources.right, /* exitOnError= */ false);
+                Cli.merge(sources.base, sources.left, sources.right, /* exitOnError= */ false, /* diff3 = */ false);
 
         assertEquals(0, merge.getSecond());
         assertEquals(expected, merge.getFirst());

src/test/resources/conflict/add_similar_fields/ExpectedDiff3.java

@@ -2,9 +2,17 @@ public class Main {
     Integer a = 2;
     Integer b = 3;
 <<<<<<< LEFT
-    Object field = Integer.valueOf(2);
+Object
 ||||||| BASE
 =======
-    Integer field = Integer.valueOf(3);
+Integer
 >>>>>>> RIGHT
+     field = Integer.valueOf(
+<<<<<<< LEFT
+2
+||||||| BASE
+=======
+3
+>>>>>>> RIGHT
+     );
 }