Fix file handle leak in FetchCommand#fetchSubmodules

The private fetchSubmodules method in the FetchCommand class creates a
Repository instance for each submodule being fetched, but never calls
closes on it.

This leads to the leaking of file handles.

Bug: 526494
Change-Id: I7070388b8b62063d9d5cd31afae3015a8388044f
Signed-off-by: Tim Hosey <timhoseydev@gmail.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

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

@@ -171,7 +171,7 @@ public class FetchCommand extends TransportCommand<FetchCommand, FetchResult> {
 			}
 			walk.setTree(revWalk.parseTree(fetchHead));
 			while (walk.next()) {
-				Repository submoduleRepo = walk.getRepository();
+				try (Repository submoduleRepo = walk.getRepository()) {
 
 					// Skip submodules that don't exist locally (have not been
 					// cloned), are not registered in the .gitmodules file, or
@@ -184,15 +184,18 @@ public class FetchCommand extends TransportCommand<FetchCommand, FetchResult> {
 					FetchRecurseSubmodulesMode recurseMode = getRecurseMode(
 							walk.getPath());
 
-				// When the fetch mode is "yes" we always fetch. When the mode
-				// is "on demand", we only fetch if the submodule's revision was
+					// When the fetch mode is "yes" we always fetch. When the
+					// mode
+					// is "on demand", we only fetch if the submodule's revision
+					// was
 					// updated to an object that is not currently present in the
 					// submodule.
 					if ((recurseMode == FetchRecurseSubmodulesMode.ON_DEMAND
 							&& !submoduleRepo.hasObject(walk.getObjectId()))
 							|| recurseMode == FetchRecurseSubmodulesMode.YES) {
 						FetchCommand f = new FetchCommand(submoduleRepo)
-							.setProgressMonitor(monitor).setTagOpt(tagOption)
+								.setProgressMonitor(monitor)
+								.setTagOpt(tagOption)
 								.setCheckFetchedObjects(checkFetchedObjects)
 								.setRemoveDeletedRefs(isRemoveDeletedRefs())
 								.setThin(thin).setRefSpecs(refSpecs)
@@ -205,6 +208,7 @@ public class FetchCommand extends TransportCommand<FetchCommand, FetchResult> {
 						results.addSubmodule(walk.getPath(), f.call());
 					}
 				}
+			}
 		} catch (IOException e) {
 			throw new JGitInternalException(e.getMessage(), e);
 		} catch (ConfigInvalidException e) {