From 438fa4a587b6e83d963bcf45fe94162f913c4fb2 Mon Sep 17 00:00:00 2001
From: Jarek Kowalski <jaak@jkowalski.net>
Date: Mon, 4 Jun 2018 17:45:31 -0700
Subject: [PATCH] whenever two blocks in index have identical times, prefer the
 non-deleted one

---
 internal/packindex/merged.go      | 20 +++++++++++++++-----
 internal/packindex/merged_test.go | 14 ++++++++++++++
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/internal/packindex/merged.go b/internal/packindex/merged.go
index d54b739d1..a1aad2104 100644
--- a/internal/packindex/merged.go
+++ b/internal/packindex/merged.go
@@ -31,14 +31,13 @@ func (m Merged) EntryCount() int {
 // GetInfo returns information about a single block. If a block is not found, returns (nil,nil)
 func (m Merged) GetInfo(contentID string) (*Info, error) {
 	var best *Info
-
 	for _, ndx := range m {
 		i, err := ndx.GetInfo(contentID)
 		if err != nil {
 			return nil, err
 		}
 		if i != nil {
-			if best == nil || i.TimestampSeconds > best.TimestampSeconds {
+			if best == nil || i.TimestampSeconds > best.TimestampSeconds || (i.TimestampSeconds == best.TimestampSeconds && !i.Deleted) {
 				best = i
 			}
 		}
@@ -53,9 +52,20 @@ type nextInfo struct {
 
 type nextInfoHeap []*nextInfo
 
-func (h nextInfoHeap) Len() int           { return len(h) }
-func (h nextInfoHeap) Less(i, j int) bool { return h[i].it.BlockID < h[j].it.BlockID }
-func (h nextInfoHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }
+func (h nextInfoHeap) Len() int { return len(h) }
+func (h nextInfoHeap) Less(i, j int) bool {
+	if a, b := h[i].it.BlockID, h[j].it.BlockID; a != b {
+		return a < b
+	}
+
+	if a, b := h[i].it.TimestampSeconds, h[j].it.TimestampSeconds; a != b {
+		return a < b
+	}
+
+	return !h[i].it.Deleted
+}
+
+func (h nextInfoHeap) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
 func (h *nextInfoHeap) Push(x interface{}) {
 	*h = append(*h, x.(*nextInfo))
 }
diff --git a/internal/packindex/merged_test.go b/internal/packindex/merged_test.go
index 0b05e72ff..08f1e40b2 100644
--- a/internal/packindex/merged_test.go
+++ b/internal/packindex/merged_test.go
@@ -14,6 +14,7 @@ func TestMerged(t *testing.T) {
 		packindex.Info{BlockID: "aabbcc", TimestampSeconds: 1, PackBlockID: "xx", PackOffset: 11},
 		packindex.Info{BlockID: "ddeeff", TimestampSeconds: 1, PackBlockID: "xx", PackOffset: 111},
 		packindex.Info{BlockID: "z010203", TimestampSeconds: 1, PackBlockID: "xx", PackOffset: 111},
+		packindex.Info{BlockID: "de1e1e", TimestampSeconds: 4, PackBlockID: "xx", PackOffset: 111},
 	)
 	if err != nil {
 		t.Fatalf("can't create index: %v", err)
@@ -21,6 +22,7 @@ func TestMerged(t *testing.T) {
 	i2, err := indexWithItems(
 		packindex.Info{BlockID: "aabbcc", TimestampSeconds: 3, PackBlockID: "yy", PackOffset: 33},
 		packindex.Info{BlockID: "xaabbcc", TimestampSeconds: 1, PackBlockID: "xx", PackOffset: 111},
+		packindex.Info{BlockID: "de1e1e", TimestampSeconds: 4, PackBlockID: "xx", PackOffset: 222, Deleted: true},
 	)
 	if err != nil {
 		t.Fatalf("can't create index: %v", err)
@@ -47,12 +49,24 @@ func TestMerged(t *testing.T) {
 	var inOrder []string
 	m.Iterate("", func(i packindex.Info) error {
 		inOrder = append(inOrder, i.BlockID)
+		if i.BlockID == "de1e1e" {
+			if i.Deleted {
+				t.Errorf("iteration preferred deleted block over non-deleted")
+			}
+		}
 		return nil
 	})
 
+	if i, err := m.GetInfo("de1e1e"); err != nil {
+		t.Errorf("error getting deleted block info: %v", err)
+	} else if i.Deleted {
+		t.Errorf("GetInfo preferred deleted block over non-deleted")
+	}
+
 	expectedInOrder := []string{
 		"aabbcc",
 		"ddeeff",
+		"de1e1e",
 		"k010203",
 		"k020304",
 		"xaabbcc",