[514382] Pre-Merge on conflict can lead to data loss

Ensure that pre-merge merges only diffs from the right side and leaves
the diffs from the left side untouched.

Contains tests.

Bug: 514382
Change-Id: Ie24a595dca3da78d2eda7ea32510d3630b8def9a
Also-by: Simon Delisle <simon.delisle@ericsson.com>
Signed-off-by: Martin Fleck <mfleck@eclipsesource.com>

4 files changed, 175 insertions, 8 deletions

diff --git a/plugins/org.eclipse.emf.compare.ide.ui.tests.git/src/org/eclipse/emf/compare/ide/ui/tests/merge/EMFResourceMappingMergerPreMergeTest.java b/plugins/org.eclipse.emf.compare.ide.ui.tests.git/src/org/eclipse/emf/compare/ide/ui/tests/merge/EMFResourceMappingMergerPreMergeTest.java
new file mode 100644
index 000000000..8e4839ea2
--- /dev/null
+++ b/plugins/org.eclipse.emf.compare.ide.ui.tests.git/src/org/eclipse/emf/compare/ide/ui/tests/merge/EMFResourceMappingMergerPreMergeTest.java
@@ -0,0 +1,163 @@
+/*******************************************************************************
+ * Copyright (c) 2017 EclipseSource Services GmbH and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *      Martin Fleck - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.emf.compare.ide.ui.tests.merge;
+
+import static org.eclipse.emf.compare.ide.ui.internal.preferences.EMFCompareUIPreferences.PRE_MERGE_MODELS_WHEN_CONFLICT;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.List;
+import java.util.Set;
+
+import org.eclipse.core.resources.IProject;
+import org.eclipse.emf.compare.ide.ui.internal.EMFCompareIDEUIPlugin;
+import org.eclipse.emf.compare.ide.ui.internal.logical.EMFResourceMappingMerger;
+import org.eclipse.emf.compare.ide.ui.tests.git.framework.GitTestRunner;
+import org.eclipse.emf.compare.ide.ui.tests.git.framework.annotations.GitInput;
+import org.eclipse.emf.compare.ide.ui.tests.git.framework.annotations.GitMerge;
+import org.eclipse.jface.preference.IPreferenceStore;
+import org.eclipse.jgit.api.Status;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.runner.RunWith;
+
+/**
+ * Test cases covering the pre-merge scenario of the {@link EMFResourceMappingMerger}.
+ * 
+ * @author Martin Fleck <mfleck@eclipsesource.com>
+ */
+@SuppressWarnings({"restriction", "nls" })
+@RunWith(GitTestRunner.class)
+public class EMFResourceMappingMergerPreMergeTest {
+
+	/** Preference store for the pre-merge setting. */
+	protected static final IPreferenceStore EMF_COMPARE_PREFS = EMFCompareIDEUIPlugin.getDefault()
+			.getPreferenceStore();
+
+	/** Cached pre-merge setting in the preference store. */
+	protected static boolean PRE_MERGE_CONFLICT_SETTING;
+
+	@BeforeClass
+	public static void setupClass() {
+		// turn pre-merge on
+		PRE_MERGE_CONFLICT_SETTING = EMF_COMPARE_PREFS.getBoolean(PRE_MERGE_MODELS_WHEN_CONFLICT);
+		EMF_COMPARE_PREFS.setValue(PRE_MERGE_MODELS_WHEN_CONFLICT, true);
+	}
+
+	@AfterClass
+	public static void tearDownClass() {
+		// restore pre-merge setting
+		EMFCompareIDEUIPlugin.getDefault().getPreferenceStore().setValue(PRE_MERGE_MODELS_WHEN_CONFLICT,
+				PRE_MERGE_CONFLICT_SETTING);
+	}
+
+	/**
+	 * Tests that we have the expected files exist when performing a pre-merge with a real conflict. The test
+	 * model looks as follows:
+	 * <ul>
+	 * <li>master: One class diagram (model) with a single class 'ClassA'</li>
+	 * <li>renameClassA: Rename of existing class to 'ClassB'</li>
+	 * <li>renameClassA_addOtherModel: Rename of existing class to 'ClassC' (REAL conflict) and addition of
+	 * other model (otherModel) which imports ClassC into the diagram (-> part of logical model)</li>
+	 * </ul>
+	 * The expected result is:
+	 * <ul>
+	 * <li>Projects: Only the single project containing the models is involved</li>
+	 * <li>Conflicts: model.uml has a rename conflict of 'ClassA' to 'ClassB' or 'ClassC'</li>
+	 * <li>PreMerge: otherModel can be merged as there is no conflict</li>
+	 * </ul>
+	 * 
+	 * @param status
+	 *            git status
+	 * @param projects
+	 *            list of involved projects
+	 */
+	@GitInput("data/premerge/bug_preMergeWithConflict.zip")
+	@GitMerge(local = "renameClassA", remote = "renameClassA_addOtherModel")
+	public void testPreMergeWithConflictL2R(Status status, List<IProject> projects) {
+		IProject project = assertSingleProject(projects);
+		assertFilesExist(project, "model.uml", "model.notation", "model.di", "otherModel.uml",
+				"otherModel.notation", "otherModel.di");
+		assertFilesConflict(status, "PreMergeWithConflict/model.uml");
+	}
+
+	/**
+	 * Tests that we have the expected files exist when performing a pre-merge with a real conflict. The test
+	 * model looks as follows:
+	 * <ul>
+	 * <li>master: One class diagram (model) with a single class 'ClassA'</li>
+	 * <li>renameClassA: Rename of existing class to 'ClassB'</li>
+	 * <li>renameClassA_addOtherModel: Rename of existing class to 'ClassC' (REAL conflict) and addition of
+	 * other model (otherModel) which imports ClassC into the diagram (-> part of logical model)</li>
+	 * </ul>
+	 * The expected result is:
+	 * <ul>
+	 * <li>Projects: Only the single project containing the models is involved</li>
+	 * <li>Conflicts: model.uml has a rename conflict of 'ClassA' to 'ClassB' or 'ClassC'</li>
+	 * <li>PreMerge: otherModel can be merged as there is no conflict</li>
+	 * </ul>
+	 * 
+	 * @param status
+	 *            git status
+	 * @param projects
+	 *            list of involved projects
+	 */
+	@GitInput("data/premerge/bug_preMergeWithConflict.zip")
+	@GitMerge(local = "renameClassA_addOtherModel", remote = "renameClassA")
+	public void testPreMergeWithConflictR2L(Status status, List<IProject> projects) {
+		IProject project = assertSingleProject(projects);
+		assertFilesExist(project, "model.uml", "model.notation", "model.di", "otherModel.uml",
+				"otherModel.notation", "otherModel.di");
+		assertFilesConflict(status, "PreMergeWithConflict/model.uml");
+	}
+
+	/**
+	 * Asserts that there is a single project and returns it.
+	 * 
+	 * @param projects
+	 *            projects
+	 * @return single project
+	 */
+	protected IProject assertSingleProject(List<IProject> projects) {
+		assertEquals(1, projects.size());
+		return projects.get(0);
+	}
+
+	/**
+	 * Asserts that all given files exist in the given project.
+	 * 
+	 * @param project
+	 *            project
+	 * @param files
+	 *            files that need to exist in the project
+	 */
+	protected void assertFilesExist(IProject project, String... files) {
+		for (String file : files) {
+			assertTrue(file + " does not exist.", project.getFile(file).exists());
+		}
+	}
+
+	/**
+	 * Asserts that the all and only the given files are conflicting.
+	 * 
+	 * @param status
+	 *            git status
+	 * @param files
+	 *            files that should be conflicting
+	 */
+	protected void assertFilesConflict(Status status, String... files) {
+		Set<String> conflicting = status.getConflicting();
+		assertEquals(files.length, conflicting.size());
+		for (String file : files) {
+			assertTrue(file + " is not conflicting.", conflicting.contains(file));
+		}
+	}
+}
diff --git a/plugins/org.eclipse.emf.compare.ide.ui.tests.git/src/org/eclipse/emf/compare/ide/ui/tests/merge/data/premerge/bug_preMergeWithConflict.zip b/plugins/org.eclipse.emf.compare.ide.ui.tests.git/src/org/eclipse/emf/compare/ide/ui/tests/merge/data/premerge/bug_preMergeWithConflict.zip
new file mode 100644
index 000000000..aa42f9860
--- /dev/null
+++ b/plugins/org.eclipse.emf.compare.ide.ui.tests.git/src/org/eclipse/emf/compare/ide/ui/tests/merge/data/premerge/bug_preMergeWithConflict.zip
diff --git a/plugins/org.eclipse.emf.compare.ide.ui.tests.git/src/org/eclipse/emf/compare/ide/ui/tests/suite/GitTests.java b/plugins/org.eclipse.emf.compare.ide.ui.tests.git/src/org/eclipse/emf/compare/ide/ui/tests/suite/GitTests.java
index f4650ca2b..f3bc3d64e 100644
--- a/plugins/org.eclipse.emf.compare.ide.ui.tests.git/src/org/eclipse/emf/compare/ide/ui/tests/suite/GitTests.java
+++ b/plugins/org.eclipse.emf.compare.ide.ui.tests.git/src/org/eclipse/emf/compare/ide/ui/tests/suite/GitTests.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2012, 2015 Obeo.
+ * Copyright (c) 2012, 2017 Obeo.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -8,16 +8,14 @@
  * Contributors:
  *     Obeo - initial API and implementation
  *     Philip Langer - adds further test cases
+ *     Martin Fleck - add EMFResourceMappingMergerPreMergeTest
  *******************************************************************************/
 package org.eclipse.emf.compare.ide.ui.tests.suite;
 
-import junit.framework.JUnit4TestAdapter;
-import junit.framework.Test;
-import junit.textui.TestRunner;
-
 import org.eclipse.emf.compare.ComparePackage;
 import org.eclipse.emf.compare.ide.ui.tests.merge.AdditiveMergeTests;
 import org.eclipse.emf.compare.ide.ui.tests.merge.DirCacheResourceVariantTreeProviderTest;
+import org.eclipse.emf.compare.ide.ui.tests.merge.EMFResourceMappingMergerPreMergeTest;
 import org.eclipse.emf.compare.ide.ui.tests.merge.GitResourceVariantTreeSubscriberTest;
 import org.eclipse.emf.compare.ide.ui.tests.merge.ResourceVariantTest;
 import org.eclipse.emf.compare.ide.ui.tests.merge.TreeWalkResourceVariantTreeProviderTest;
@@ -40,6 +38,10 @@ import org.junit.runner.RunWith;
 import org.junit.runners.Suite;
 import org.junit.runners.Suite.SuiteClasses;
 
+import junit.framework.JUnit4TestAdapter;
+import junit.framework.Test;
+import junit.textui.TestRunner;
+
 @RunWith(Suite.class)
 @SuiteClasses({AdditiveMergeTests.class, DirCacheResourceVariantTreeProviderTest.class,
 		// GitLogicalMergeTest.class,
@@ -58,7 +60,8 @@ import org.junit.runners.Suite.SuiteClasses;
 		ResourceVariantTest.class, ResourceUtilPathTest.class, RevisionedURIConverterTest.class,
 		// StrategyRecursiveModelTest.class,
 		// StrategyRecursiveModelWithDeepProjectTest.class,
-		ThreadedModelResolverResolutionTest.class, TreeWalkResourceVariantTreeProviderTest.class, })
+		ThreadedModelResolverResolutionTest.class, TreeWalkResourceVariantTreeProviderTest.class,
+		EMFResourceMappingMergerPreMergeTest.class })
 public class GitTests {
 	/**
 	 * Launches the test with the given arguments.
diff --git a/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/logical/EMFResourceMappingMerger.java b/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/logical/EMFResourceMappingMerger.java
index 03f3ecd24..788272b53 100644
--- a/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/logical/EMFResourceMappingMerger.java
+++ b/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/logical/EMFResourceMappingMerger.java
@@ -10,11 +10,12 @@
  *     Philip Langer - bugs 461713, 465331, 470268, 476363, 476417, 486940, refactorings
  *     Alexandra Buzila - bugs 470332, 478620
  *     Stefan Dirix - bug 507050
- *     Martin Fleck - bug 512562
+ *     Martin Fleck - bug 512562, 514382
  *******************************************************************************/
 package org.eclipse.emf.compare.ide.ui.internal.logical;
 
 import static com.google.common.base.Predicates.alwaysFalse;
+import static com.google.common.collect.Iterables.filter;
 import static org.eclipse.emf.compare.utils.EMFComparePredicates.fromSide;
 
 import com.google.common.collect.ImmutableMap;
@@ -325,7 +326,7 @@ public class EMFResourceMappingMerger implements IResourceMappingMerger {
 	private Set<URI> performPreMerge(Comparison comparison, SubMonitor subMonitor) {
 		final Monitor emfMonitor = BasicMonitor.toMonitor(subMonitor);
 		final Set<URI> conflictingURIs = new LinkedHashSet<URI>();
-		for (Diff next : comparison.getDifferences()) {
+		for (Diff next : filter(comparison.getDifferences(), fromSide(DifferenceSource.RIGHT))) {
 			doMergeForDiff(emfMonitor, conflictingURIs, next);
 		}
 		return conflictingURIs;