[441172] Extend findMasterEquivalence to not only check eOpposites

Currently the findMasterEquivalence method only considers equivalences
whose reference is the eOpposite of the given diff. But sometimes the
equivalence's reference is the same as the one given by the diff. The
findMasterEquivalence method is extended to handle these cases too.

Includes testcases for this issue.

Bug: 441172
Signed-off-by: Stefan Dirix <sdirix@eclipsesource.com>
Also-by: Laurent Goubet <laurent.goubet@obeo.fr>
Change-Id: Ic3678939c0798c9993c41d329f6c0d4e4d098c27

4 files changed, 97 insertions, 2 deletions

diff --git a/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/equi/data/EquiInputData.java b/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/equi/data/EquiInputData.java
index 593f669ae..1d8a3a0c5 100644
--- a/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/equi/data/EquiInputData.java
+++ b/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/equi/data/EquiInputData.java
@@ -105,6 +105,14 @@ public class EquiInputData extends AbstractInputData {
 		return loadFromClassLoader("c6/right.nodes"); //$NON-NLS-1$
 	}
 
+	public Resource getC7Left() throws IOException {
+		return loadFromClassLoader("c7/left.nodes"); //$NON-NLS-1$
+	}
+
+	public Resource getC7Right() throws IOException {
+		return loadFromClassLoader("c7/right.nodes"); //$NON-NLS-1$
+	}
+
 	public Resource getD1Left() throws IOException {
 		return loadFromClassLoader("d1/left.nodes"); //$NON-NLS-1$
 	}
diff --git a/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/equi/data/c7/left.nodes b/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/equi/data/c7/left.nodes
new file mode 100644
index 000000000..518c8a03a
--- /dev/null
+++ b/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/equi/data/c7/left.nodes
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<nodes:Node
+    xmi:version="2.0"
+    xmlns:xmi="http://www.omg.org/XMI"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns:nodes="http://www.eclipse.org/emf/compare/tests/nodes"
+    xmi:id="_root"
+    name="Root">
+  <containmentRef1 xsi:type="nodes:NodeOppositeRefOneToMany" name="a" source="b"/>
+  <containmentRef1 xsi:type="nodes:NodeOppositeRefOneToMany" name="b" destination="a"/>
+</nodes:Node>
diff --git a/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/equi/data/c7/right.nodes b/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/equi/data/c7/right.nodes
new file mode 100644
index 000000000..6bef905e6
--- /dev/null
+++ b/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/equi/data/c7/right.nodes
@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<nodes:Node
+    xmi:version="2.0"
+    xmlns:xmi="http://www.omg.org/XMI"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns:nodes="http://www.eclipse.org/emf/compare/tests/nodes"
+    xmi:id="_root"
+    name="Root">
+  <containmentRef1 xsi:type="nodes:NodeOppositeRefOneToMany" name="a" source="a" destination="a"/>
+</nodes:Node>
diff --git a/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/merge/MultipleMergeTest.java b/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/merge/MultipleMergeTest.java
index b168b18fe..8fb7477bb 100644
--- a/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/merge/MultipleMergeTest.java
+++ b/plugins/org.eclipse.emf.compare.tests/src/org/eclipse/emf/compare/tests/merge/MultipleMergeTest.java
@@ -1123,7 +1123,7 @@ public class MultipleMergeTest {
 		 */
 		mergerRegistry.getHighestRankingMerger(unsetDiff).copyLeftToRight(unsetDiff, new BasicMonitor());
 
-		// merge the remaining diffsS
+		// merge the remaining differences
 		for (Diff diff : differences) {
 			if (diff != unsetDiff) {
 				mergerRegistry.getHighestRankingMerger(diff).copyLeftToRight(diff, new BasicMonitor());
@@ -1157,7 +1157,7 @@ public class MultipleMergeTest {
 		 */
 		mergerRegistry.getHighestRankingMerger(unsetDiff).copyRightToLeft(unsetDiff, new BasicMonitor());
 
-		// merge the remaining diffsS
+		// merge the remaining differences
 		for (Diff diff : differences) {
 			if (diff != unsetDiff) {
 				mergerRegistry.getHighestRankingMerger(diff).copyRightToLeft(diff, new BasicMonitor());
@@ -1170,6 +1170,72 @@ public class MultipleMergeTest {
 	}
 
 	@Test
+	public void testEquivalenceC7LtoR() throws IOException {
+		final Resource left = equivalenceInput.getC7Left();
+		final Resource right = equivalenceInput.getC7Right();
+
+		final IComparisonScope scope = new DefaultComparisonScope(left, right, null);
+		Comparison comparison = EMFCompare.builder().build().compare(scope);
+
+		final List<Diff> differences = comparison.getDifferences();
+		assertEquals(4, differences.size());
+
+		final ReferenceChange deleteDiff = (ReferenceChange)Iterators.find(differences.iterator(),
+				removedFromReference("Root.a", "destination", "Root.a"));
+
+		/*
+		 * Merge the deleteDiff first. If the merger blindly merges the deleteDiff without proper looking at
+		 * its equivalences, the equivalences will also be set to status "merged" although the reference to be
+		 * added is still missing.
+		 */
+		mergerRegistry.getHighestRankingMerger(deleteDiff).copyLeftToRight(deleteDiff, new BasicMonitor());
+
+		// merge the remaining differences
+		for (Diff diff : differences) {
+			if (diff != deleteDiff) {
+				mergerRegistry.getHighestRankingMerger(diff).copyLeftToRight(diff, new BasicMonitor());
+			}
+		}
+
+		// check if no differences between models are left
+		comparison = EMFCompare.builder().build().compare(scope);
+		assertEquals(0, comparison.getDifferences().size());
+	}
+
+	@Test
+	public void testEquivalenceC7RtoL() throws IOException {
+		final Resource left = equivalenceInput.getC7Left();
+		final Resource right = equivalenceInput.getC7Right();
+
+		final IComparisonScope scope = new DefaultComparisonScope(left, right, null);
+		Comparison comparison = EMFCompare.builder().build().compare(scope);
+
+		final List<Diff> differences = comparison.getDifferences();
+		assertEquals(4, differences.size());
+
+		final ReferenceChange deleteDiff = (ReferenceChange)Iterators.find(differences.iterator(),
+				addedToReference("Root.b", "destination", "Root.a"));
+
+		/*
+		 * Merge the diff resulting in a delete first. If the merger blindly merges the deleteDiff without
+		 * proper looking at its equivalences, the equivalences will also be set to status "merged" although
+		 * the reference to be added is still missing.
+		 */
+		mergerRegistry.getHighestRankingMerger(deleteDiff).copyRightToLeft(deleteDiff, new BasicMonitor());
+
+		// merge the remaining differences
+		for (Diff diff : differences) {
+			if (diff != deleteDiff) {
+				mergerRegistry.getHighestRankingMerger(diff).copyRightToLeft(diff, new BasicMonitor());
+			}
+		}
+
+		// check if no differences between models are left
+		comparison = EMFCompare.builder().build().compare(scope);
+		assertEquals(0, comparison.getDifferences().size());
+	}
+
+	@Test
 	public void testMergeAllDiffsTwice() throws IOException {
 		final IdentifierMatchInputData inputData = new IdentifierMatchInputData();
 		final Resource left = inputData.getExtlibraryLeft();