LfsProtocolServlet: Improve error on getLargeFileRepository failure

Externalize the error message and make it more specific. Also emit
an error log.

Change-Id: Ie7b1c90c54673bfb8e133fb0aa19a117d4ca6587
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

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

@@ -33,4 +33,5 @@ Import-Package: com.google.gson;version="[2.2.4,3.0.0)",
  org.eclipse.jgit.nls;version="[4.7.0,4.8.0)",
  org.eclipse.jgit.transport.http;version="[4.7.0,4.8.0)",
  org.eclipse.jgit.transport.http.apache;version="[4.7.0,4.8.0)",
- org.eclipse.jgit.util;version="[4.7.0,4.8.0)"
+ org.eclipse.jgit.util;version="[4.7.0,4.8.0)",
+ org.slf4j;version="[1.7.0,2.0.0)"

org.eclipse.jgit.lfs.server/src/org/eclipse/jgit/lfs/server/LfsProtocolServlet.java

@@ -59,6 +59,7 @@ import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.io.Reader;
 import java.io.Writer;
+import java.text.MessageFormat;
 import java.util.List;
 
 import javax.servlet.ServletException;
@@ -75,6 +76,9 @@ import org.eclipse.jgit.lfs.errors.LfsRepositoryReadOnly;
 import org.eclipse.jgit.lfs.errors.LfsUnauthorized;
 import org.eclipse.jgit.lfs.errors.LfsUnavailable;
 import org.eclipse.jgit.lfs.errors.LfsValidationError;
+import org.eclipse.jgit.lfs.internal.LfsText;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import com.google.gson.FieldNamingPolicy;
 import com.google.gson.Gson;
@@ -88,6 +92,8 @@ import com.google.gson.GsonBuilder;
  * @since 4.3
  */
 public abstract class LfsProtocolServlet extends HttpServlet {
+	private static Logger LOG = LoggerFactory
+			.getLogger(LfsProtocolServlet.class);
 
 	private static final long serialVersionUID = 1L;
 
@@ -183,7 +189,10 @@ public abstract class LfsProtocolServlet extends HttpServlet {
 		try {
 			repo = getLargeFileRepository(request, path);
 			if (repo == null) {
-				throw new LfsException("unexpected error"); //$NON-NLS-1$
+				String error = MessageFormat
+						.format(LfsText.get().lfsFailedToGetRepository, path);
+				LOG.error(error);
+				throw new LfsException(error);
 			}
 			res.setStatus(SC_OK);
 			TransferHandler handler = TransferHandler

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

@@ -8,3 +8,4 @@ repositoryNotFound=Repository {0} not found
 repositoryReadOnly=Repository {0} is read-only
 lfsUnavailable=LFS is not available for repository {0}
 lfsUnathorized=Not authorized to perform operation {0} on repository {1}
+lfsFailedToGetRepository=failed to get repository {0}

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

@@ -68,4 +68,5 @@ public class LfsText extends TranslationBundle {
 	/***/ public String repositoryReadOnly;
 	/***/ public String lfsUnavailable;
 	/***/ public String lfsUnathorized;
+	/***/ public String lfsFailedToGetRepository;
 }