Implement --force option in FetchCommand and CLI fetch command

Change-Id: I42cdb57b8fb54ce466d1958391f12f911045327f
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/FetchTest.java

@@ -91,6 +91,19 @@ public class FetchTest extends CLIRepositoryTestCase {
 		assertEquals(" * [new tag]         tag        -> tag", result[2]);
 	}
 
+	@Test
+	public void testFetchForceUpdate() throws Exception {
+		String[] result = execute(
+				"git fetch test refs/heads/master:refs/remotes/origin/master");
+		assertEquals(" * [new branch]      master     -> origin/master",
+				result[1]);
+		assertEquals(" * [new tag]         tag        -> tag", result[2]);
+		remoteGit.commit().setAmend(true).setMessage("amended").call();
+		result = execute(
+				"git fetch -f test refs/heads/master:refs/remotes/origin/master");
+		assertEquals("", result[0]);
+	}
+
 	@Test
 	public void testFetchNoTags() throws Exception {
 		String[] result = execute("git fetch --no-tags test refs/heads/master:refs/remotes/origin/master");

org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties

@@ -343,6 +343,7 @@ usage_forEachRefOutput=for-each-ref output
 usage_forceCheckout=when switching branches, proceed even if the index or the working tree differs from HEAD
 usage_forceClean=required to delete files or directories
 usage_forceCreateBranchEvenExists=force create branch even exists
+usage_forcedFetch=force ref update fetch option
 usage_forceReplacingAnExistingTag=force replacing an existing tag
 usage_getAndSetOptions=Get and set repository or global options
 usage_groups=Restrict manifest projects to ones with specified group(s), use "-" for excluding [default|all|G1,G2,G3|G4,-G5,-G6]

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Fetch.java

@@ -100,6 +100,9 @@ class Fetch extends AbstractFetchCommand implements FetchCommand.Callback {
 		tags = Boolean.FALSE;
 	}
 
+	@Option(name = "--force", usage = "usage_forcedFetch", aliases = { "-f" })
+	private Boolean force;
+
 	private FetchRecurseSubmodulesMode recurseSubmodules;
 
 	@Option(name = "--recurse-submodules", usage = "usage_recurseSubmodules")
@@ -155,6 +158,9 @@ class Fetch extends AbstractFetchCommand implements FetchCommand.Callback {
 			if (quiet == null || !quiet.booleanValue())
 				fetch.setProgressMonitor(new TextProgressMonitor(errw));
 			fetch.setRecurseSubmodules(recurseSubmodules).setCallback(this);
+			if (force != null) {
+				fetch.setForceUpdate(force.booleanValue());
+			}
 
 			FetchResult result = fetch.call();
 			if (result.getTrackingRefUpdates().isEmpty()

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/FetchCommandTest.java

@@ -101,6 +101,25 @@ public class FetchCommandTest extends RepositoryTestCase {
 				db.resolve(tagRef.getObjectId().getName()));
 	}
 
+	@Test
+	public void testForcedFetch() throws Exception {
+		remoteGit.commit().setMessage("commit").call();
+		remoteGit.commit().setMessage("commit2").call();
+		git.fetch().setRemote("test")
+				.setRefSpecs("refs/heads/master:refs/heads/master").call();
+
+		remoteGit.commit().setAmend(true).setMessage("amended").call();
+		FetchResult res = git.fetch().setRemote("test")
+				.setRefSpecs("refs/heads/master:refs/heads/master").call();
+		assertEquals(RefUpdate.Result.REJECTED,
+				res.getTrackingRefUpdate("refs/heads/master").getResult());
+		res = git.fetch().setRemote("test")
+				.setRefSpecs("refs/heads/master:refs/heads/master")
+				.setForceUpdate(true).call();
+		assertEquals(RefUpdate.Result.FORCED,
+				res.getTrackingRefUpdate("refs/heads/master").getResult());
+	}
+
 	@Test
 	public void fetchShouldAutoFollowTag() throws Exception {
 		remoteGit.commit().setMessage("commit").call();

org.eclipse.jgit/src/org/eclipse/jgit/api/FetchCommand.java

@@ -105,6 +105,8 @@ public class FetchCommand extends TransportCommand<FetchCommand, FetchResult> {
 
 	private Callback callback;
 
+	private boolean isForceUpdate;
+
 	/**
 	 * Callback for status of fetch operation.
 	 *
@@ -198,7 +200,8 @@ public class FetchCommand extends TransportCommand<FetchCommand, FetchResult> {
 								.setTagOpt(tagOption)
 								.setCheckFetchedObjects(checkFetchedObjects)
 								.setRemoveDeletedRefs(isRemoveDeletedRefs())
-								.setThin(thin).setRefSpecs(refSpecs)
+								.setThin(thin)
+								.setRefSpecs(applyOptions(refSpecs))
 								.setDryRun(dryRun)
 								.setRecurseSubmodules(recurseMode);
 						configure(f);
@@ -237,8 +240,8 @@ public class FetchCommand extends TransportCommand<FetchCommand, FetchResult> {
 				transport.setTagOpt(tagOption);
 			transport.setFetchThin(thin);
 			configure(transport);
-
-			FetchResult result = transport.fetch(monitor, refSpecs);
+			FetchResult result = transport.fetch(monitor,
+					applyOptions(refSpecs));
 			if (!repo.isBare()) {
 				fetchSubmodules(result);
 			}
@@ -261,6 +264,17 @@ public class FetchCommand extends TransportCommand<FetchCommand, FetchResult> {
 
 	}
 
+	private List<RefSpec> applyOptions(List<RefSpec> refSpecs2) {
+		if (!isForceUpdate()) {
+			return refSpecs2;
+		}
+		List<RefSpec> updated = new ArrayList<>(3);
+		for (RefSpec refSpec : refSpecs2) {
+			updated.add(refSpec.setForceUpdate(true));
+		}
+		return updated;
+	}
+
 	/**
 	 * Set the mode to be used for recursing into submodules.
 	 *
@@ -517,4 +531,27 @@ public class FetchCommand extends TransportCommand<FetchCommand, FetchResult> {
 		this.callback = callback;
 		return this;
 	}
+
+	/**
+	 * Whether fetch --force option is enabled
+	 *
+	 * @return whether refs affected by the fetch are updated forcefully
+	 * @since 5.0
+	 */
+	public boolean isForceUpdate() {
+		return this.isForceUpdate;
+	}
+
+	/**
+	 * Set fetch --force option
+	 *
+	 * @param force
+	 *            whether to update refs affected by the fetch forcefully
+	 * @return this command
+	 * @since 5.0
+	 */
+	public FetchCommand setForceUpdate(boolean force) {
+		this.isForceUpdate = force;
+		return this;
+	}
 }