Shallow fetch: Pass along "shallow"s in unparsed-wants case, too

Since 84d2738ff2 (Don't skip want validation when the client sends no
haves, 2013-06-21), this branch is not taken.  Process the
"shallow"s anyway as a defensive measure in case the code path gets
revived.

Change-Id: Idfb834825d77f51e17191c1635c9d78c78738cfd
Signed-off-by: Jonathan Nieder <jrn@google.com>

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/pack/PackWriter.java

@@ -709,11 +709,32 @@ public class PackWriter implements AutoCloseable {
 	public void preparePack(ProgressMonitor countingMonitor,
 			@NonNull Set<? extends ObjectId> want,
 			@NonNull Set<? extends ObjectId> have) throws IOException {
+		preparePack(countingMonitor,
+				want, have, Collections.<ObjectId> emptySet());
+	}
+
+	/**
+	 * Prepare the list of objects to be written to the pack stream.
+	 * <p>
+	 * Like {@link #preparePack(ProgressMonitor, Set, Set)} but also allows
+	 * specifying commits that should not be walked past ("shallow" commits).
+	 * The caller is responsible for filtering out commits that should not
+	 * be shallow any more ("unshallow" commits as in {@link #setShallowPack})
+	 * from the shallow set.
+	 *
+	 * @since 4.5
+	 */
+	public void preparePack(ProgressMonitor countingMonitor,
+			@NonNull Set<? extends ObjectId> want,
+			@NonNull Set<? extends ObjectId> have,
+			@NonNull Set<? extends ObjectId> shallow) throws IOException {
 		ObjectWalk ow;
-		if (shallowPack)
+		if (shallowPack) {
 			ow = new DepthWalk.ObjectWalk(reader, depth);
-		else
+		} else {
 			ow = new ObjectWalk(reader);
+		}
+		ow.assumeShallow(shallow);
 		preparePack(countingMonitor, ow, want, have);
 	}
 

org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java

@@ -1492,7 +1492,7 @@ public class UploadPack {
 			}
 
 			if (wantAll.isEmpty()) {
-				pw.preparePack(pm, wantIds, commonBase);
+				pw.preparePack(pm, wantIds, commonBase, clientShallowCommits);
 			} else {
 				walk.reset();