Fix selection lost on revision bump

6 files changed, 56 insertions, 11 deletions

diff --git a/src/chunklist.go b/src/chunklist.go
index bd98999d..ce4a56a0 100644
--- a/src/chunklist.go
+++ b/src/chunklist.go
@@ -41,6 +41,13 @@ func (c *Chunk) IsFull() bool {
 	return c.count == chunkSize
 }
 
+func (c *Chunk) lastIndex(minValue int32) int32 {
+	if c.count == 0 {
+		return minValue
+	}
+	return c.items[c.count-1].Index() + 1 // Exclusive
+}
+
 func (cl *ChunkList) lastChunk() *Chunk {
 	return cl.chunks[len(cl.chunks)-1]
 }
diff --git a/src/matcher.go b/src/matcher.go
index 49d39730..daaa69ce 100644
--- a/src/matcher.go
+++ b/src/matcher.go
@@ -165,6 +165,7 @@ func (m *Matcher) scan(request MatchRequest) (*Merger, bool) {
 	}
 
 	minIndex := request.chunks[0].items[0].Index()
+	maxIndex := request.chunks[numChunks-1].lastIndex(minIndex)
 	cancelled := util.NewAtomicBool(false)
 
 	slices := m.sliceChunks(request.chunks)
@@ -236,7 +237,7 @@ func (m *Matcher) scan(request MatchRequest) (*Merger, bool) {
 		partialResult := <-resultChan
 		partialResults[partialResult.index] = partialResult.matches
 	}
-	return NewMerger(pattern, partialResults, m.sort && request.pattern.sortable, m.tac, request.revision, minIndex), false
+	return NewMerger(pattern, partialResults, m.sort && request.pattern.sortable, m.tac, request.revision, minIndex, maxIndex), false
 }
 
 // Reset is called to interrupt/signal the ongoing search
diff --git a/src/merger.go b/src/merger.go
index fee8a59a..688f3571 100644
--- a/src/merger.go
+++ b/src/merger.go
@@ -4,7 +4,7 @@ import "fmt"
 
 // EmptyMerger is a Merger with no data
 func EmptyMerger(revision revision) *Merger {
-	return NewMerger(nil, [][]Result{}, false, false, revision, 0)
+	return NewMerger(nil, [][]Result{}, false, false, revision, 0, 0)
 }
 
 // Merger holds a set of locally sorted lists of items and provides the view of
@@ -22,14 +22,16 @@ type Merger struct {
 	pass     bool
 	revision revision
 	minIndex int32
+	maxIndex int32
 }
 
 // PassMerger returns a new Merger that simply returns the items in the
 // original order
 func PassMerger(chunks *[]*Chunk, tac bool, revision revision) *Merger {
-	var minIndex int32
+	var minIndex, maxIndex int32
 	if len(*chunks) > 0 {
 		minIndex = (*chunks)[0].items[0].Index()
+		maxIndex = (*chunks)[len(*chunks)-1].lastIndex(minIndex)
 	}
 	mg := Merger{
 		pattern:  nil,
@@ -38,7 +40,8 @@ func PassMerger(chunks *[]*Chunk, tac bool, revision revision) *Merger {
 		count:    0,
 		pass:     true,
 		revision: revision,
-		minIndex: minIndex}
+		minIndex: minIndex,
+		maxIndex: maxIndex}
 
 	for _, chunk := range *mg.chunks {
 		mg.count += chunk.count
@@ -47,7 +50,7 @@ func PassMerger(chunks *[]*Chunk, tac bool, revision revision) *Merger {
 }
 
 // NewMerger returns a new Merger
-func NewMerger(pattern *Pattern, lists [][]Result, sorted bool, tac bool, revision revision, minIndex int32) *Merger {
+func NewMerger(pattern *Pattern, lists [][]Result, sorted bool, tac bool, revision revision, minIndex int32, maxIndex int32) *Merger {
 	mg := Merger{
 		pattern:  pattern,
 		lists:    lists,
@@ -59,7 +62,8 @@ func NewMerger(pattern *Pattern, lists [][]Result, sorted bool, tac bool, revisi
 		final:    false,
 		count:    0,
 		revision: revision,
-		minIndex: minIndex}
+		minIndex: minIndex,
+		maxIndex: maxIndex}
 
 	for _, list := range mg.lists {
 		mg.count += len(list)
diff --git a/src/merger_test.go b/src/merger_test.go
index a6b28f6e..85e4795d 100644
--- a/src/merger_test.go
+++ b/src/merger_test.go
@@ -58,7 +58,7 @@ func TestMergerUnsorted(t *testing.T) {
 	cnt := len(items)
 
 	// Not sorted: same order
-	mg := NewMerger(nil, lists, false, false, revision{}, 0)
+	mg := NewMerger(nil, lists, false, false, revision{}, 0, 0)
 	assert(t, cnt == mg.Length(), "Invalid Length")
 	for i := 0; i < cnt; i++ {
 		assert(t, items[i] == mg.Get(i), "Invalid Get")
@@ -70,7 +70,7 @@ func TestMergerSorted(t *testing.T) {
 	cnt := len(items)
 
 	// Sorted sorted order
-	mg := NewMerger(nil, lists, true, false, revision{}, 0)
+	mg := NewMerger(nil, lists, true, false, revision{}, 0, 0)
 	assert(t, cnt == mg.Length(), "Invalid Length")
 	sort.Sort(ByRelevance(items))
 	for i := 0; i < cnt; i++ {
@@ -80,7 +80,7 @@ func TestMergerSorted(t *testing.T) {
 	}
 
 	// Inverse order
-	mg2 := NewMerger(nil, lists, true, false, revision{}, 0)
+	mg2 := NewMerger(nil, lists, true, false, revision{}, 0, 0)
 	for i := cnt - 1; i >= 0; i-- {
 		if items[i] != mg2.Get(i) {
 			t.Error("Not sorted", items[i], mg2.Get(i))
diff --git a/src/terminal.go b/src/terminal.go
index adffbab5..748a2dfc 100644
--- a/src/terminal.go
+++ b/src/terminal.go
@@ -1680,12 +1680,12 @@ func (t *Terminal) UpdateList(merger *Merger) {
 			// Trimmed by --tail: filter selection by index
 			filtered := make(map[int32]selectedItem)
 			minIndex := merger.minIndex
-			maxIndex := minIndex + int32(merger.Length())
+			maxIndex := merger.maxIndex
 			for k, v := range t.selected {
 				var included bool
 				if maxIndex > minIndex {
 					included = k >= minIndex && k < maxIndex
-				} else { // int32 overflow [==>   <==]
+				} else if maxIndex < minIndex { // int32 overflow [==>   <==]
 					included = k >= minIndex || k < maxIndex
 				}
 				if included {
diff --git a/test/test_core.rb b/test/test_core.rb
index cf4cd237..4d21c19c 100644
--- a/test/test_core.rb
+++ b/test/test_core.rb
@@ -2002,4 +2002,37 @@ class TestCore < TestInteractive
     tmux.until { assert_equal 0, it.select_count }
     tmux.until { refute it.any_include?('Selected') }
   end
+
+  def test_preserve_selection_on_revision_bump
+    tmux.send_keys %(seq 100 | #{FZF} --multi --sync --query "'1" --bind 'a:select-all+change-header(pressed a),b:change-header(pressed b)+change-nth(1),c:exclude'), :Enter
+    tmux.until do
+      assert_equal 20, it.match_count
+      assert_equal 0, it.select_count
+    end
+    tmux.send_keys :a
+    tmux.until do
+      assert_equal 20, it.match_count
+      assert_equal 20, it.select_count
+      assert it.any_include?('pressed a')
+    end
+    tmux.send_keys :b
+    tmux.until do
+      assert_equal 20, it.match_count
+      assert_equal 20, it.select_count
+      refute it.any_include?('pressed a')
+      assert it.any_include?('pressed b')
+    end
+    tmux.send_keys :a
+    tmux.until do
+      assert_equal 20, it.match_count
+      assert_equal 20, it.select_count
+      assert it.any_include?('pressed a')
+      refute it.any_include?('pressed b')
+    end
+    tmux.send_keys :c
+    tmux.until do
+      assert_equal 19, it.match_count
+      assert_equal 19, it.select_count
+    end
+  end
 end