PushCommand: allow users to disable use of bitmaps for push

Reachability bitmaps are designed to speed up the "counting objects"
phase of generating a pack during a clone or fetch. They are not
optimized for Git clients sending a small topic branch via "git push".
In some cases (see [1]), using reachability bitmaps during "git push"
can cause significant performance regressions.

Add PushCommand#setUseBitmaps(boolean) to allow users to tell "git push"
not to use bitmaps.

[1]: https://lore.kernel.org/git/87zhoz8b9o.fsf@evledraar.gmail.com/

Change-Id: I7fb7d26084ec63ddfa7249cf58abb85929b30e56
Signed-off-by: kylezhao <kylezhao@tencent.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/TransportTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/TransportTest.java
index 5ae440f1d2..2019c263fb 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/TransportTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/TransportTest.java
@@ -242,6 +242,37 @@ public class TransportTest extends SampleDataRepositoryTestCase {
 	}
 
 	@Test
+	public void testOpenPushUseBitmaps() throws Exception {
+		URIish uri = new URIish("file://" + db.getWorkTree().getAbsolutePath());
+		// default
+		try (Transport transport = Transport.open(uri)) {
+			try (PushConnection pushConnection = transport.openPush()) {
+				assertTrue(pushConnection instanceof BasePackPushConnection);
+				BasePackPushConnection basePackPushConnection = (BasePackPushConnection) pushConnection;
+				assertEquals(true, basePackPushConnection.isUseBitmaps());
+			}
+		}
+		// true
+		try (Transport transport = Transport.open(uri)) {
+			transport.setPushUseBitmaps(true);
+			try (PushConnection pushConnection = transport.openPush()) {
+				assertTrue(pushConnection instanceof BasePackPushConnection);
+				BasePackPushConnection basePackPushConnection = (BasePackPushConnection) pushConnection;
+				assertEquals(true, basePackPushConnection.isUseBitmaps());
+			}
+		}
+		// false
+		try (Transport transport = Transport.open(uri)) {
+			transport.setPushUseBitmaps(false);
+			try (PushConnection pushConnection = transport.openPush()) {
+				assertTrue(pushConnection instanceof BasePackPushConnection);
+				BasePackPushConnection basePackPushConnection = (BasePackPushConnection) pushConnection;
+				assertEquals(false, basePackPushConnection.isUseBitmaps());
+			}
+		}
+	}
+
+	@Test
 	public void testSpi() {
 		List<TransportProtocol> protocols = Transport.getTransportProtocols();
 		assertNotNull(protocols);