From effacec817ed4a0050af8730a3dd86f679a373ef Mon Sep 17 00:00:00 2001
From: ognots <ognots@protonmail.com>
Date: Tue, 21 Jan 2020 13:13:21 -0500
Subject: [PATCH] range over right index to prevent bounds errors

the test scenario 'healthyHeadCheckWindow5' was causing index out of bounds errors.
the second range function in checkWindow was iterating over the incorrect slice of cids.
should be comparing latest items in slices first
---
 cmd/lotus-health/main.go      |   4 +-
 cmd/lotus-health/main_test.go | 138 ++++++++++++++++++++++++++++++++++
 2 files changed, 140 insertions(+), 2 deletions(-)

diff --git a/cmd/lotus-health/main.go b/cmd/lotus-health/main.go
index 664f196fd..fc6b7de09 100644
--- a/cmd/lotus-health/main.go
+++ b/cmd/lotus-health/main.go
@@ -135,14 +135,14 @@ func checkWindow(ch chan CidWindow, t int) bool {
 		windowLen := len(window)
 		if windowLen >= t {
 		cidWindow:
-			for i, cids := range window {
+			for i := range window {
 				next := windowLen - 1 - i
 				// if array length is different, head is changing
 				if next >= 1 && len(window[next]) != len(window[next-1]) {
 					break cidWindow
 				}
 				// if cids are different, head is changing
-				for j := range cids {
+				for j := range window[next] {
 					if next >= 1 && window[next][j] != window[next-1][j] {
 						break cidWindow
 					}
diff --git a/cmd/lotus-health/main_test.go b/cmd/lotus-health/main_test.go
index a31115cba..568877994 100644
--- a/cmd/lotus-health/main_test.go
+++ b/cmd/lotus-health/main_test.go
@@ -31,6 +31,7 @@ func TestCheckWindow(t *testing.T) {
 	ch := make(chan CidWindow, 1)
 	och := make(chan bool, 1)
 	threshold := 3
+
 	go func() {
 		och <- checkWindow(ch, threshold)
 	}()
@@ -51,6 +52,107 @@ func TestCheckWindow(t *testing.T) {
 	case ok := <-och:
 		assert.True(ok)
 	}
+
+	go func() {
+		och <- checkWindow(ch, threshold)
+	}()
+	var healthyHeadCheckWindow1 CidWindow
+	healthyHeadCheckWindow1 = appendCIDsToWindow(healthyHeadCheckWindow1, []cid.Cid{
+		makeCID("bbcd"),
+		makeCID("bbfe"),
+	}, threshold)
+	healthyHeadCheckWindow1 = appendCIDsToWindow(healthyHeadCheckWindow1, []cid.Cid{
+		makeCID("bbcd"),
+		makeCID("bbfe"),
+		makeCID("abcd"),
+	}, threshold)
+	healthyHeadCheckWindow1 = appendCIDsToWindow(healthyHeadCheckWindow1, []cid.Cid{
+		makeCID("abcd"),
+	}, threshold)
+	ch <- healthyHeadCheckWindow1
+	select {
+	case ok := <-och:
+		assert.True(ok)
+	}
+
+	go func() {
+		och <- checkWindow(ch, threshold)
+	}()
+	var healthyHeadCheckWindow2 CidWindow
+	healthyHeadCheckWindow2 = appendCIDsToWindow(healthyHeadCheckWindow2, []cid.Cid{
+		makeCID("bbcd"),
+		makeCID("bbfe"),
+	}, threshold)
+	healthyHeadCheckWindow2 = appendCIDsToWindow(healthyHeadCheckWindow2, []cid.Cid{
+		makeCID("abcd"),
+	}, threshold)
+	ch <- healthyHeadCheckWindow2
+	select {
+	case ok := <-och:
+		assert.True(ok)
+	}
+
+	go func() {
+		och <- checkWindow(ch, threshold)
+	}()
+	var healthyHeadCheckWindow3 CidWindow
+	healthyHeadCheckWindow3 = appendCIDsToWindow(healthyHeadCheckWindow3, []cid.Cid{
+		makeCID("abcd"),
+	}, threshold)
+	healthyHeadCheckWindow3 = appendCIDsToWindow(healthyHeadCheckWindow3, []cid.Cid{
+		makeCID("bbcd"),
+		makeCID("bbfe"),
+	}, threshold)
+	ch <- healthyHeadCheckWindow3
+	select {
+	case ok := <-och:
+		assert.True(ok)
+	}
+
+	go func() {
+		och <- checkWindow(ch, threshold)
+	}()
+	var healthyHeadCheckWindow4 CidWindow
+	healthyHeadCheckWindow4 = appendCIDsToWindow(healthyHeadCheckWindow4, []cid.Cid{
+		makeCID("bbcd"),
+		makeCID("bbfe"),
+	}, threshold)
+	ch <- healthyHeadCheckWindow4
+	select {
+	case ok := <-och:
+		assert.True(ok)
+	}
+
+	go func() {
+		och <- checkWindow(ch, 5)
+	}()
+	var healthyHeadCheckWindow5 CidWindow
+	healthyHeadCheckWindow5 = appendCIDsToWindow(healthyHeadCheckWindow5, []cid.Cid{
+		makeCID("bbcd"),
+		makeCID("bbfe"),
+		makeCID("bbff"),
+	}, 5)
+	healthyHeadCheckWindow5 = appendCIDsToWindow(healthyHeadCheckWindow5, []cid.Cid{
+		makeCID("bbcd"),
+		makeCID("bbfe"),
+	}, 5)
+	healthyHeadCheckWindow5 = appendCIDsToWindow(healthyHeadCheckWindow5, []cid.Cid{
+		makeCID("abcd"),
+	}, 5)
+	healthyHeadCheckWindow5 = appendCIDsToWindow(healthyHeadCheckWindow5, []cid.Cid{
+		makeCID("cbcd"),
+		makeCID("cbfe"),
+	}, 5)
+	healthyHeadCheckWindow5 = appendCIDsToWindow(healthyHeadCheckWindow5, []cid.Cid{
+		makeCID("cbcd"),
+		makeCID("cbfe"),
+	}, 5)
+	ch <- healthyHeadCheckWindow5
+	select {
+	case ok := <-och:
+		assert.True(ok)
+	}
+
 	go func() {
 		och <- checkWindow(ch, threshold)
 	}()
@@ -73,6 +175,42 @@ func TestCheckWindow(t *testing.T) {
 		assert.False(ok)
 	}
 
+	go func() {
+		och <- checkWindow(ch, threshold)
+	}()
+	var unhealthyHeadCheckWindow1 CidWindow
+	unhealthyHeadCheckWindow1 = appendCIDsToWindow(unhealthyHeadCheckWindow1, []cid.Cid{
+		makeCID("abcd"),
+		makeCID("fbcd"),
+	}, threshold)
+	unhealthyHeadCheckWindow1 = appendCIDsToWindow(unhealthyHeadCheckWindow1, []cid.Cid{
+		makeCID("abcd"),
+		makeCID("fbcd"),
+	}, threshold)
+	ch <- unhealthyHeadCheckWindow1
+	select {
+	case ok := <-och:
+		assert.True(ok)
+	}
+
+	go func() {
+		och <- checkWindow(ch, threshold)
+	}()
+	var unhealthyHeadCheckWindow2 CidWindow
+	unhealthyHeadCheckWindow2 = appendCIDsToWindow(unhealthyHeadCheckWindow2, []cid.Cid{
+		makeCID("abcd"),
+	}, threshold)
+	unhealthyHeadCheckWindow2 = appendCIDsToWindow(unhealthyHeadCheckWindow2, []cid.Cid{
+		makeCID("abcd"),
+	}, threshold)
+	unhealthyHeadCheckWindow2 = appendCIDsToWindow(unhealthyHeadCheckWindow2, []cid.Cid{
+		makeCID("abcd"),
+	}, threshold)
+	ch <- unhealthyHeadCheckWindow2
+	select {
+	case ok := <-och:
+		assert.False(ok)
+	}
 }
 
 func makeCID(s string) cid.Cid {