fix(vt): align row ID exhaustion boundary

commit: 3c2478bf710314e71111c7d4f5c14a811863a5bc
author: brice · 2mo ago · 2026-08-02 21:11 UTC
committer: brice · 2mo ago · 2026-08-03 17:54 UTC
parent: cc001e4
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

2 files · +43 -1

M pkg/vt/row_id.go +1 -1


@@ -5,7 +5,7 @@ package vt
5	5		type RowID uint64
6	6
7	7		func (s *Screen) nextRowIDValue() RowID {
8		-	if s.nextRowID >= ^RowID(0)-1 {
	8	+	if s.nextRowID >= ^RowID(0)-2 {
9	9		panic("vt: row ID space exhausted")
10	10		}
11	11		s.nextRowID++


@@ -5,7 +5,7 @@ package vt
5		type RowID uint64	5		type RowID uint64
6			6
7		func (s *Screen) nextRowIDValue() RowID {	7		func (s *Screen) nextRowIDValue() RowID {
8	-	if s.nextRowID >= ^RowID(0)-1 {	8	+	if s.nextRowID >= ^RowID(0)-2 {
9		panic("vt: row ID space exhausted")	9		panic("vt: row ID space exhausted")
10		}	10		}
11		s.nextRowID++	11		s.nextRowID++

M pkg/vt/row_id_persistence_test.go +42 -0


@@ -43,6 +43,48 @@ func TestHistoryAppendRejectsExhaustedRowIDCounter(t *testing.T) {
43	43		require.Error(t, history.Append(historyRow("row"), LineBound{End: 3}))
44	44		}
45	45
	46	+	func TestScreenRowIDBoundaryMatchesHistoryPersistence(t *testing.T) {
	47	+	const maxPersistedRowID = ^RowID(0) - 2
	48	+	for _, test := range []struct {
	49	+	name string
	50	+	current RowID
	51	+	want RowID
	52	+	persist bool
	53	+	}{
	54	+	{name: "last persistable ID", current: maxPersistedRowID - 1, want: maxPersistedRowID, persist: true},
	55	+	{name: "first non-persistable ID", current: maxPersistedRowID, want: maxPersistedRowID + 1},
	56	+	} {
	57	+	t.Run(test.name, func(t *testing.T) {
	58	+	screen := NewScreen(1, 1)
	59	+	screen.nextRowID = test.current
	60	+	allocate := func() {
	61	+	require.Equal(t, test.want, screen.nextRowIDValue())
	62	+	}
	63	+	if !test.persist {
	64	+	require.Panics(t, allocate)
	65	+	return
	66	+	}
	67	+
	68	+	allocate()
	69	+	row := historyRow("x")
	70	+	screen.buffer.rowIDs[0] = test.want
	71	+	screen.buffer.frame.Row(0)[0] = row[0]
	72	+	screen.buffer.boundaries[0] = LineBound{End: 1}
	73	+	transcript, err := screen.RecoveryTranscriptSnapshot().Marshal()
	74	+	require.NoError(t, err)
	75	+	view, err := UnmarshalHistory(transcript)
	76	+	require.NoError(t, err)
	77	+	require.Equal(t, test.want, view.RowID(0))
	78	+	require.Equal(t, test.want+1, view.NextRowID())
	79	+
	80	+	history := NewHistory(HistoryConfig{MaxRows: 1, ChunkRows: 1})
	81	+	require.NoError(t, history.Append(row, LineBound{End: 1}, screen.RowID(0)))
	82	+	_, err = MarshalHistory(history.SealAndView())
	83	+	require.NoError(t, err)
	84	+	})
	85	+	}
	86	+	}
	87	+
46	88		func TestHistoryCodecRejectsMissingRowIDsOnMarshal(t *testing.T) {
47	89		_, err := MarshalHistory(HistoryView{
48	90		chunks: []*HistoryChunk{{rows: [][]renderer.Cell{historyRow("row")}, bounds: []LineBound{{End: 3}}}},


@@ -43,6 +43,48 @@ func TestHistoryAppendRejectsExhaustedRowIDCounter(t *testing.T) {
43	require.Error(t, history.Append(historyRow("row"), LineBound{End: 3}))	43		require.Error(t, history.Append(historyRow("row"), LineBound{End: 3}))
44	}	44		}
45		45
		46	+	func TestScreenRowIDBoundaryMatchesHistoryPersistence(t *testing.T) {
		47	+	const maxPersistedRowID = ^RowID(0) - 2
		48	+	for _, test := range []struct {
		49	+	name string
		50	+	current RowID
		51	+	want RowID
		52	+	persist bool
		53	+	}{
		54	+	{name: "last persistable ID", current: maxPersistedRowID - 1, want: maxPersistedRowID, persist: true},
		55	+	{name: "first non-persistable ID", current: maxPersistedRowID, want: maxPersistedRowID + 1},
		56	+	} {
		57	+	t.Run(test.name, func(t *testing.T) {
		58	+	screen := NewScreen(1, 1)
		59	+	screen.nextRowID = test.current
		60	+	allocate := func() {
		61	+	require.Equal(t, test.want, screen.nextRowIDValue())
		62	+	}
		63	+	if !test.persist {
		64	+	require.Panics(t, allocate)
		65	+	return
		66	+	}
		67	+
		68	+	allocate()
		69	+	row := historyRow("x")
		70	+	screen.buffer.rowIDs[0] = test.want
		71	+	screen.buffer.frame.Row(0)[0] = row[0]
		72	+	screen.buffer.boundaries[0] = LineBound{End: 1}
		73	+	transcript, err := screen.RecoveryTranscriptSnapshot().Marshal()
		74	+	require.NoError(t, err)
		75	+	view, err := UnmarshalHistory(transcript)
		76	+	require.NoError(t, err)
		77	+	require.Equal(t, test.want, view.RowID(0))
		78	+	require.Equal(t, test.want+1, view.NextRowID())
		79	+
		80	+	history := NewHistory(HistoryConfig{MaxRows: 1, ChunkRows: 1})
		81	+	require.NoError(t, history.Append(row, LineBound{End: 1}, screen.RowID(0)))
		82	+	_, err = MarshalHistory(history.SealAndView())
		83	+	require.NoError(t, err)
		84	+	})
		85	+	}
		86	+	}
		87	+
46	func TestHistoryCodecRejectsMissingRowIDsOnMarshal(t *testing.T) {	88		func TestHistoryCodecRejectsMissingRowIDsOnMarshal(t *testing.T) {
47	_, err := MarshalHistory(HistoryView{	89		_, err := MarshalHistory(HistoryView{
48	chunks: []*HistoryChunk{{rows: [][]renderer.Cell{historyRow("row")}, bounds: []LineBound{{End: 3}}}},	90		chunks: []*HistoryChunk{{rows: [][]renderer.Cell{historyRow("row")}, bounds: []LineBound{{End: 3}}}},