[JGIT PATCH 2/2] More aggressively clear flags during RevWalk.reset

Shawn O. Pearce· Sep 16, 2008, 19:34 UTC · lore

[JGIT PATCH 1/2] Paper bag fix RevWalk.reset after inMergeBase is used

We need to remove delayedFreeFlags from carryFlags anytime we mark those delayedFreeFlags as actually freeFlags. In other words we do not want to continue carrying a flag which we have now freed and will recycle for a different use in the future, one which may not want to be carried automatically onto parent commits during revision traversal.

I had the boolean expression incorrect (call it a typo). The correct way to remove set b from a is "a &= ~b" not "a &= b".

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
---
 .../src/org/spearce/jgit/revwalk/RevWalk.java      |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

Show changes to org.spearce.jgit/src/org/spearce/jgit/revwalk/RevWalk.java +1 −1

diff --git a/org.spearce.jgit/src/org/spearce/jgit/revwalk/RevWalk.java b/org.spearce.jgit/src/org/spearce/jgit/revwalk/RevWalk.java
index 079432c..5cd7f71 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/revwalk/RevWalk.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/revwalk/RevWalk.java
@@ -824,7 +824,7 @@ void freeFlag(final int mask) {
 	private void finishDelayedFreeFlags() {
 		if (delayFreeFlags != 0) {
 			freeFlags |= delayFreeFlags;
-			carryFlags &= delayFreeFlags;
+			carryFlags &= ~delayFreeFlags;
 			delayFreeFlags = 0;
 		}
 	}

-- 
1.6.0.2.389.g421e0

Shawn O. Pearce· Sep 16, 2008, 19:34 UTC · re: Shawn O. Pearce · lore

We cannot rely upon SEEN to tell us if the commit has flags we must clear, as some forms of RevWalk usage can get flags put in places that don't have a clear SEEN trail leading to them. To ensure we have correctly reset the graph we need to follow down any chain which has any flag we are not going to retain across the reset, making the correct test ~retain (and not just SEEN).

This fixes an issue I identified in an application that makes heavy use of the same RevWalk instance, constantly resetting it and executing down different parts of the same DAG instance.

Some executions still had UNINTERESTING colored on commits, even though they should have been cleared by the prior reset. The clear failed as there was not a SEEN path leading into the previously UNINTERESTING (but now interesting) commit. This missing SEEN path occurred because markUninteresting() runs RevComit.carryFlags(), pushing the UNINTERESTING flag as far down the DAG as we have parsed. Not all of those DAG nodes may get visited in a traversal (so they lack SEEN), but they must get reset in order to reuse the same DAG instance.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
---
 .../src/org/spearce/jgit/revwalk/RevWalk.java      |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

Show changes to org.spearce.jgit/src/org/spearce/jgit/revwalk/RevWalk.java +6 −2

diff --git a/org.spearce.jgit/src/org/spearce/jgit/revwalk/RevWalk.java b/org.spearce.jgit/src/org/spearce/jgit/revwalk/RevWalk.java
index 5cd7f71..d7e4c58 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/revwalk/RevWalk.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/revwalk/RevWalk.java
@@ -887,10 +887,11 @@ public final void resetRetain(final RevFlag... retainFlags) {
 	protected void reset(int retainFlags) {
 		finishDelayedFreeFlags();
 		retainFlags |= PARSED;
+		final int clearFlags = ~retainFlags;
 
 		final FIFORevQueue q = new FIFORevQueue();
 		for (final RevCommit c : roots) {
-			if ((c.flags & SEEN) == 0)
+			if ((c.flags & clearFlags) == 0)
 				continue;
 			c.flags &= retainFlags;
 			c.reset();
@@ -901,10 +902,13 @@ protected void reset(int retainFlags) {
 			final RevCommit c = q.next();
 			if (c == null)
 				break;
+			if (c.parents == null)
+				continue;
 			for (final RevCommit p : c.parents) {
-				if ((p.flags & SEEN) == 0)
+				if ((p.flags & clearFlags) == 0)
 					continue;
 				p.flags &= retainFlags;
+				p.reset();
 				q.add(p);
 			}
 		}

-- 
1.6.0.2.389.g421e0

patch, 2 partsMore aggressively clear flags during RevWalk.reset