馃 (Agent generated text, read next message first please)
Narrowing a buffer whose reflowed lines do not fit in the scrollback panics:
panic: runtime error: index out of range [-1]
CircularList[...].Set circularlist.go:84
Buffer.reflowSmaller buffer.go:449
Buffer.Resize buffer.go:252
Repro (fails on dae5128):
b := NewBuffer(BufferOptions{Cols: 20, Rows: 2, Scrollback: 2, TabStopWidth: 8, HasScrollback: true})
b.FillViewportRows(nil)
attrs := &AttributeData{Extended: &ExtendedAttrs{}}
for y := range b.Lines.Length() {
for i, ch := range []rune("ABCDEFGHIJKLMNOPQRST") {
b.Lines.Get(y).SetCellFromCodepoint(i, uint32(ch), 1, attrs)
}
}
b.Resize(2, 2)It also happens at realistic sizes: an 80x24 terminal with 1000 lines of scrollback full of long wrapped lines panics when resized to 40 columns.
Cause: in the rearrange loop of reflowSmaller (buffer.go, around line 448), the inner loop decrements the write index i once per inserted line but only checks nextI >= 0. If the reflow adds more lines than the list can hold, i goes below 0. Set then panics, or overwrites an unrelated slot if the list has wrapped.
Suggested fix: also bound the inner loop by i:
-for nextI := len(nextToInsert.newLines) - 1; nextI >= 0; nextI-- {
+for nextI := len(nextToInsert.newLines) - 1; nextI >= 0 && i >= 0; nextI-- {A patch with a regression test is on this branch: https://github.com/eugenioenko/xterm-go/tree/fix/reflow-smaller-negative-index
馃 (Agent generated text, read next message first please)
Narrowing a buffer whose reflowed lines do not fit in the scrollback panics:
Repro (fails on
dae5128):It also happens at realistic sizes: an 80x24 terminal with 1000 lines of scrollback full of long wrapped lines panics when resized to 40 columns.
Cause: in the rearrange loop of
reflowSmaller(buffer.go, around line 448), the inner loop decrements the write indexionce per inserted line but only checksnextI >= 0. If the reflow adds more lines than the list can hold,igoes below 0.Setthen panics, or overwrites an unrelated slot if the list has wrapped.Suggested fix: also bound the inner loop by
i:A patch with a regression test is on this branch: https://github.com/eugenioenko/xterm-go/tree/fix/reflow-smaller-negative-index