From cc2a223fea20975b04d9c4d0b4febf1c7b3937a4 Mon Sep 17 00:00:00 2001
From: Minh Thai <mthai@google.com>
Date: Wed, 6 Mar 2019 15:25:10 -0800
Subject: [PATCH] Do not retain commit body in RevWalk for reachability checks

Commit body contains the message that is not needed for reachability checks, and
takes up memory unnecessarily.

Change-Id: I0c7f6da249bf9c4fda9dc9e62e809322c68effce
Signed-off-by: Minh Thai <mthai@google.com>
---
 .../eclipse/jgit/internal/storage/dfs/DfsReftableDatabase.java  | 1 +
 org.eclipse.jgit/src/org/eclipse/jgit/lib/RefUpdate.java        | 2 ++
 org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java       | 2 ++
 .../src/org/eclipse/jgit/transport/BasePackFetchConnection.java | 1 +
 .../src/org/eclipse/jgit/transport/BaseReceivePack.java         | 1 +
 .../src/org/eclipse/jgit/transport/FetchProcess.java            | 1 +
 6 files changed, 8 insertions(+)

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsReftableDatabase.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsReftableDatabase.java
index 83394bb92..384273dff 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsReftableDatabase.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsReftableDatabase.java
@@ -315,6 +315,7 @@ protected boolean compareAndPut(Ref oldRef, @Nullable Ref newRef)
 			throws IOException {
 		ReceiveCommand cmd = toCommand(oldRef, newRef);
 		try (RevWalk rw = new RevWalk(getRepository())) {
+			rw.setRetainBody(false);
 			newBatchUpdate().setAllowNonFastForwards(true).addCommand(cmd)
 					.execute(rw, NullProgressMonitor.INSTANCE);
 		}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/RefUpdate.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/RefUpdate.java
index 1ce152834..784162766 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/RefUpdate.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/RefUpdate.java
@@ -599,6 +599,7 @@ public Result forceUpdate() throws IOException {
 	 */
 	public Result update() throws IOException {
 		try (RevWalk rw = new RevWalk(getRepository())) {
+			rw.setRetainBody(false);
 			return update(rw);
 		}
 	}
@@ -646,6 +647,7 @@ Result execute(Result status) throws IOException {
 	 */
 	public Result delete() throws IOException {
 		try (RevWalk rw = new RevWalk(getRepository())) {
+			rw.setRetainBody(false);
 			return delete(rw);
 		}
 	}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
index a61897a65..625ddf101 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
@@ -489,6 +489,7 @@ public ObjectId resolve(String revstr)
 			throws AmbiguousObjectException, IncorrectObjectTypeException,
 			RevisionSyntaxException, IOException {
 		try (RevWalk rw = new RevWalk(this)) {
+			rw.setRetainBody(false);
 			Object resolved = resolve(rw, revstr);
 			if (resolved instanceof String) {
 				final Ref ref = findRef((String) resolved);
@@ -515,6 +516,7 @@ public ObjectId resolve(String revstr)
 	public String simplify(String revstr)
 			throws AmbiguousObjectException, IOException {
 		try (RevWalk rw = new RevWalk(this)) {
+			rw.setRetainBody(true);
 			Object resolved = resolve(rw, revstr);
 			if (resolved != null)
 				if (resolved instanceof String)
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/BasePackFetchConnection.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/BasePackFetchConnection.java
index ed7465c82..d54ae10f6 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/BasePackFetchConnection.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/BasePackFetchConnection.java
@@ -272,6 +272,7 @@ public BasePackFetchConnection(PackTransport packTransport) {
 
 		if (local != null) {
 			walk = new RevWalk(local);
+			walk.setRetainBody(false);
 			reachableCommits = new RevCommitList<>();
 			REACHABLE = walk.newFlag("REACHABLE"); //$NON-NLS-1$
 			COMMON = walk.newFlag("COMMON"); //$NON-NLS-1$
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/BaseReceivePack.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/BaseReceivePack.java
index 6f17620d9..2946e9835 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/BaseReceivePack.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/BaseReceivePack.java
@@ -314,6 +314,7 @@ public Set<String> getCapabilities() {
 	protected BaseReceivePack(Repository into) {
 		db = into;
 		walk = new RevWalk(db);
+		walk.setRetainBody(false);
 
 		TransferConfig tc = db.getConfig().get(TransferConfig.KEY);
 		objectChecker = tc.newReceiveObjectChecker();
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchProcess.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchProcess.java
index 681ae125c..e584440b3 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchProcess.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchProcess.java
@@ -200,6 +200,7 @@ else if (tagopt == TagOpt.FETCH_TAGS)
 				.setAllowNonFastForwards(true)
 				.setRefLogMessage("fetch", true); //$NON-NLS-1$
 		try (RevWalk walk = new RevWalk(transport.local)) {
+			walk.setRetainBody(false);
 			if (monitor instanceof BatchingProgressMonitor) {
 				((BatchingProgressMonitor) monitor).setDelayStart(
 						250, TimeUnit.MILLISECONDS);