fix(screen): keep REP eligibility across empty writes after a lone ESC

commit: f05313741739bc8875e186e4ed01788fec63d6a0
author: brice · 7d ago · 2026-10-15 02:39 UTC
parent: 6209370
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

2 files · +22 -7

M screen.go +5 -2


@@ -184,8 +184,11 @@ func (s *Screen) Write(data []byte) {
184	184		if len(s.escapeBuf) == 0 {
185	185		s.trimEscapeBuffers()
186	186		} else if isKittyEscapeContinuation(s.escapeBuf, data) {
187		-	// A Kitty APC sits between any earlier graphic and what follows.
188		-	s.lastPrinted = 0
	187	+	// A Kitty APC sits between any earlier graphic and what follows. An
	188	+	// empty write has not identified the buffered escape yet.
	189	+	if len(data) > 0 {
	190	+	s.lastPrinted = 0
	191	+	}
189	192		prefix := s.escapeBuf
190	193		s.escapeBuf = nil
191	194		data = s.continueKittyEscape(prefix, data)

 	if len(s.escapeBuf) == 0 {
 		s.trimEscapeBuffers()
 	} else if isKittyEscapeContinuation(s.escapeBuf, data) {
-		// A Kitty APC sits between any earlier graphic and what follows.
+		// A Kitty APC sits between any earlier graphic and what follows. An
-		s.lastPrinted = 0
+		// empty write has not identified the buffered escape yet.
+		if len(data) > 0 {
+			s.lastPrinted = 0
+		}
 		prefix := s.escapeBuf
 		s.escapeBuf = nil
 		data = s.continueKittyEscape(prefix, data)

M screen_charset_test.go +17 -5


@@ -60,11 +60,23 @@ func TestSoftResetCursorAppearance(t *testing.T) {
60	60		}
61	61
62	62		func TestRepeatSplitAcrossWrites(t *testing.T) {
63		-	s := NewScreen(10, 1)
64		-	s.Write([]byte("a\x1b["))
65		-	s.Write([]byte("2b"))
66		-	if got := strings.TrimRight(lineText(s, 0), " "); got != "aaa" {
67		-	t.Fatalf("line = %q, want %q", got, "aaa")
	63	+	tests := []struct {
	64	+	name string
	65	+	writes []string
	66	+	}{
	67	+	{name: "split inside CSI", writes: []string{"a\x1b[", "2b"}},
	68	+	{name: "empty write after lone ESC", writes: []string{"a\x1b", "", "[2b"}},
	69	+	}
	70	+	for _, tt := range tests {
	71	+	t.Run(tt.name, func(t *testing.T) {
	72	+	s := NewScreen(10, 1)
	73	+	for _, w := range tt.writes {
	74	+	s.Write([]byte(w))
	75	+	}
	76	+	if got := strings.TrimRight(lineText(s, 0), " "); got != "aaa" {
	77	+	t.Fatalf("line = %q, want %q", got, "aaa")
	78	+	}
	79	+	})
68	80		}
69	81		}
70	82


@@ -60,11 +60,23 @@ func TestSoftResetCursorAppearance(t *testing.T) {
60		}	60		}
61			61
62		func TestRepeatSplitAcrossWrites(t *testing.T) {	62		func TestRepeatSplitAcrossWrites(t *testing.T) {
63	-	s := NewScreen(10, 1)	63	+	tests := []struct {
64	-	s.Write([]byte("a\x1b["))	64	+	name string
65	-	s.Write([]byte("2b"))	65	+	writes []string
66	-	if got := strings.TrimRight(lineText(s, 0), " "); got != "aaa" {	66	+	}{
67	-	t.Fatalf("line = %q, want %q", got, "aaa")	67	+	{name: "split inside CSI", writes: []string{"a\x1b[", "2b"}},
			68	+	{name: "empty write after lone ESC", writes: []string{"a\x1b", "", "[2b"}},
			69	+	}
			70	+	for _, tt := range tests {
			71	+	t.Run(tt.name, func(t *testing.T) {
			72	+	s := NewScreen(10, 1)
			73	+	for _, w := range tt.writes {
			74	+	s.Write([]byte(w))
			75	+	}
			76	+	if got := strings.TrimRight(lineText(s, 0), " "); got != "aaa" {
			77	+	t.Fatalf("line = %q, want %q", got, "aaa")
			78	+	}
			79	+	})
68		}	80		}
69		}	81		}
70			82