From 611ea02ceabec3a6a160cba5d716e63847911fe7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Magiera?= <magik6k@gmail.com>
Date: Thu, 5 Sep 2019 09:57:12 +0200
Subject: [PATCH] chain events: More logical apply order

---
 chain/events/events_called.go |  4 ++-
 chain/events/events_height.go |  5 ++-
 chain/events/events_test.go   | 67 +++++++++++++++++++++++++++++++++--
 3 files changed, 72 insertions(+), 4 deletions(-)

diff --git a/chain/events/events_called.go b/chain/events/events_called.go
index cb7d96236..2eadf6836 100644
--- a/chain/events/events_called.go
+++ b/chain/events/events_called.go
@@ -86,7 +86,9 @@ func (e *calledEvents) headChangeCalled(rev, app []*types.TipSet) error {
 		e.handleReverts(ts)
 	}
 
-	for _, ts := range app {
+	tail := len(app) - 1
+	for i := range app {
+		ts := app[tail-i]
 		// called triggers
 
 		e.checkNewCalls(ts)
diff --git a/chain/events/events_height.go b/chain/events/events_height.go
index 8bfb144a8..41ee8099f 100644
--- a/chain/events/events_height.go
+++ b/chain/events/events_height.go
@@ -47,7 +47,10 @@ func (e *heightEvents) headChangeAt(rev, app []*types.TipSet) error {
 		}
 	}
 
-	for _, ts := range app {
+	tail := len(app) - 1
+	for i := range app {
+		ts := app[tail-i]
+
 		if err := e.tsc.add(ts); err != nil {
 			return err
 		}
diff --git a/chain/events/events_test.go b/chain/events/events_test.go
index 7a3abe582..37a1d653a 100644
--- a/chain/events/events_test.go
+++ b/chain/events/events_test.go
@@ -98,7 +98,7 @@ func (fcs *fakeCS) advance(rev, app int, msgs map[int]cid.Cid) { // todo: allow
 		require.NoError(fcs.t, fcs.tsc.revert(ts))
 	}
 
-	var apps []*types.TipSet
+	apps := make([]*types.TipSet, app)
 	for i := 0; i < app; i++ {
 		fcs.h++
 
@@ -110,7 +110,7 @@ func (fcs *fakeCS) advance(rev, app int, msgs map[int]cid.Cid) { // todo: allow
 		ts := makeTs(fcs.t, fcs.h, mc)
 		require.NoError(fcs.t, fcs.tsc.add(ts))
 
-		apps = append(apps, ts)
+		apps[app-i-1] = ts
 	}
 
 	err := fcs.sub(revs, apps)
@@ -446,3 +446,66 @@ func TestCalledTimeout(t *testing.T) {
 	fcs.advance(0, 5, nil)
 	require.False(t, called)
 }
+
+func TestCalledOrder(t *testing.T) {
+	fcs := &fakeCS{
+		t: t,
+		h: 1,
+
+		msgs: map[cid.Cid]fakeMsg{},
+		tsc:  newTSCache(2 * build.ForkLengthThreshold),
+	}
+	require.NoError(t, fcs.tsc.add(makeTs(t, 1, dummyCid)))
+
+	events := NewEvents(fcs)
+
+	t0123, err := address.NewFromString("t0123")
+	require.NoError(t, err)
+
+	at := 0
+
+	err = events.Called(func(ts *types.TipSet) (d bool, m bool, e error) {
+		return false, true, nil
+	}, func(msg *types.Message, ts *types.TipSet, curH uint64) (bool, error) {
+		switch at {
+		case 0:
+			require.Equal(t, uint64(1), msg.Nonce)
+			require.Equal(t, uint64(3), ts.Height())
+		case 1:
+			require.Equal(t, uint64(2), msg.Nonce)
+			require.Equal(t, uint64(4), ts.Height())
+		default:
+			t.Fatal("apply should only get called twice, at: ", at)
+		}
+		at++
+		return true, nil
+	}, func(ts *types.TipSet) error {
+		switch at {
+		case 2:
+			require.Equal(t, uint64(4), ts.Height())
+		case 3:
+			require.Equal(t, uint64(3), ts.Height())
+		default:
+			t.Fatal("revert should only get called twice, at: ", at)
+		}
+		at++
+		return nil
+	}, 3, 20, t0123, 5)
+	require.NoError(t, err)
+
+	fcs.advance(0, 10, map[int]cid.Cid{
+		1: fcs.fakeMsgs(fakeMsg{
+			bmsgs: []*types.Message{
+				{To: t0123, Method: 5, Nonce: 1},
+			},
+		}),
+		2: fcs.fakeMsgs(fakeMsg{
+			bmsgs: []*types.Message{
+				{To: t0123, Method: 5, Nonce: 2},
+			},
+		}),
+	})
+
+	fcs.advance(9, 1, nil)
+
+}