LFS: Enable LFS support for the CLI, better error handling

Enable LFS support for the CLI by registering the according filters.

Errors during filter creation must be propagated up the call stack, as a
failure to create a filter should be treated as fatal if the filter is
required.

Change-Id: I3833757839bdda97cd01b6c21c1613d199e2692d
Signed-off-by: Markus Duft <markus.duft@ssi-schaefer.com>

org.eclipse.jgit.lfs.server.test/META-INF/MANIFEST.MF

  org.eclipse.jetty.util.security;version="[9.4.5,10.0.0)",
  org.eclipse.jetty.util.thread;version="[9.4.5,10.0.0)",
  org.eclipse.jgit.api;version="[4.11.0,4.12.0)",
+ org.eclipse.jgit.api.errors;version="[4.11.0,4.12.0)",
  org.eclipse.jgit.internal.storage.file;version="[4.11.0,4.12.0)",
  org.eclipse.jgit.junit;version="[4.11.0,4.12.0)",
  org.eclipse.jgit.junit.http;version="[4.11.0,4.12.0)",

org.eclipse.jgit.lfs.server.test/tst/org/eclipse/jgit/lfs/server/fs/CheckoutTest.java

 import java.nio.file.Path;
 
 import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.api.errors.JGitInternalException;
 import org.eclipse.jgit.junit.JGitTestUtil;
 import org.eclipse.jgit.junit.TestRepository;
 import org.eclipse.jgit.lfs.BuiltinLFS;
+import org.eclipse.jgit.lfs.lib.Constants;
 import org.eclipse.jgit.lfs.lib.LongObjectId;
+import org.eclipse.jgit.lib.ConfigConstants;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.lib.StoredConfig;
 import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
 				.create(tmp.resolve(".git").toFile());
 		db.create();
 		StoredConfig cfg = db.getConfig();
-		cfg.setString("filter", "lfs", "usejgitbuiltin", "true");
-		cfg.setString("lfs", null, "url", server.getURI().toString() + "/lfs");
+		cfg.setBoolean(ConfigConstants.CONFIG_FILTER_SECTION, Constants.LFS,
+				ConfigConstants.CONFIG_KEY_USEJGITBUILTIN, true);
+		cfg.setBoolean(ConfigConstants.CONFIG_FILTER_SECTION, Constants.LFS,
+				ConfigConstants.CONFIG_KEY_REQUIRED, false);
+		cfg.setString(Constants.LFS, null, "url",
+				server.getURI().toString() + "/lfs");
 		cfg.save();
 
 		tdb = new TestRepository<>(db);
 				server.getRequests().toString());
 	}
 
+	@Test(expected = JGitInternalException.class)
+	public void testUnknownContentRequired() throws Exception {
+		StoredConfig cfg = tdb.getRepository().getConfig();
+		cfg.setBoolean(ConfigConstants.CONFIG_FILTER_SECTION, Constants.LFS,
+				ConfigConstants.CONFIG_KEY_REQUIRED, true);
+		cfg.save();
+
+		// must throw
+		git.checkout().setName("test").call();
+	}
+
 	@Test
 	public void testKnownContent() throws Exception {
 		putContent(

org.eclipse.jgit.lfs/resources/org/eclipse/jgit/lfs/internal/LfsText.properties

 invalidLongId=Invalid id: {0}
 invalidLongIdLength=Invalid id length {0}; should be {1}
 lfsUnavailable=LFS is not available for repository {0}
+protocolError=LFS Protocol Error {0}: {1}
 requiredHashFunctionNotAvailable=Required hash function {0} not available.
 repositoryNotFound=Repository {0} not found
 repositoryReadOnly=Repository {0} is read-only

org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/SmudgeFilter.java

 			Protocol.Response resp = gson.fromJson(reader,
 					Protocol.Response.class);
 			for (Protocol.ObjectInfo o : resp.objects) {
+				if (o.error != null) {
+					throw new IOException(
+							MessageFormat.format(LfsText.get().protocolError,
+									o.error.code, o.error.message));
+				}
 				if (o.actions == null) {
 					continue;
 				}

org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/internal/LfsText.java

 	/***/ public String invalidLongId;
 	/***/ public String invalidLongIdLength;
 	/***/ public String lfsUnavailable;
+	/***/ public String protocolError;
 	/***/ public String requiredHashFunctionNotAvailable;
 	/***/ public String repositoryNotFound;
 	/***/ public String repositoryReadOnly;

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

 	 * @throws java.lang.Exception
 	 */
 	public static void main(final String[] argv) throws Exception {
+		// make sure built-in filters are registered
+		BuiltinLFS.register();
+
 		new Main().run(argv);
 	}
 

org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java

 import org.eclipse.jgit.errors.MissingObjectException;
 import org.eclipse.jgit.events.WorkingTreeModifiedEvent;
 import org.eclipse.jgit.internal.JGitText;
+import org.eclipse.jgit.lib.ConfigConstants;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.CoreConfig.AutoCRLF;
 import org.eclipse.jgit.lib.CoreConfig.EolStreamType;
 	private static void runBuiltinFilterCommand(Repository repo,
 			CheckoutMetadata checkoutMetadata, ObjectLoader ol,
 			OutputStream channel) throws MissingObjectException, IOException {
+		boolean isMandatory = repo.getConfig().getBoolean(
+				ConfigConstants.CONFIG_FILTER_SECTION, "lfs",
+				ConfigConstants.CONFIG_KEY_REQUIRED, false);
 		FilterCommand command = null;
 		try {
 			command = FilterCommandRegistry.createFilterCommand(
 					channel);
 		} catch (IOException e) {
 			LOG.error(JGitText.get().failedToDetermineFilterDefinition, e);
-			// In case an IOException occurred during creating of the command
-			// then proceed as if there would not have been a builtin filter.
-			ol.copyTo(channel);
+			if (!isMandatory) {
+				// In case an IOException occurred during creating of the
+				// command then proceed as if there would not have been a
+				// builtin filter (only if the filter is not mandatory).
+				ol.copyTo(channel);
+			} else {
+				throw e;
+			}
 		}
 		if (command != null) {
 			while (command.run() != -1) {