[vim/vim] popup: refresh popup mask when scrollbar visibility changes (PR #20098)

mattn

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Apr 29, 2026, 8:50:06 PM (2 days ago) Apr 29

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popup_adjust_position() decides whether to refresh popup_mask by comparing a fixed set of fields (w_winrow, w_wincol, w_leftcol, w_popup_leftoff, w_width, w_height). It does not consider w_has_scrollbar, and w_width is the popup's inner content width, which doesn't include the scrollbar column. So when popup_settext() shrinks the buffer enough that the scrollbar disappears, none of the tracked fields change, the mask refresh is skipped, and the cell that held the old border / scrollbar is never repainted, leaving stray characters on the right of the popup.

The regression was introduced in 9.2.0112, which replaced the global redraw_win_later(UPD_NOT_VALID) in f_popup_settext() with a popup-local redraw. Before that, the global must_redraw propagation forced may_update_popup_mask() to refresh the mask anyway, masking this gap.

For a centered popup, losing the scrollbar drops extra_width by 1, so w_wincol = (Columns - w_width - extra_width) / 2 would normally shift by 1 and trip the existing org_wincol != w_wincol branch. Whether the shift actually happens depends on the parity of Columns due to integer truncation, so the bug only surfaced at odd terminal widths or with pos: 'topleft' popups whose w_wincol is anchored.

Fix: also compare w_has_scrollbar in the change detection.

Closes #20092

You can view, comment on, or merge this pull request online at:

https://github.com/vim/vim/pull/20098

Commit Summary

c23ea5b popup: refresh popup mask when scrollbar visibility changes

File Changes

(1 file)

M src/popupwin.c (4)

Patch Links:

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mattn

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Apr 29, 2026, 8:51:33 PM (2 days ago) Apr 29

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mattn left a comment (vim/vim#20098)

I'll add test.

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mattn

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Apr 29, 2026, 8:55:29 PM (2 days ago) Apr 29

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@mattn pushed 1 commit.

5287bdd popup: add test for scrollbar-disappearing redraw

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mattn

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Apr 29, 2026, 9:34:24 PM (2 days ago) Apr 29

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@mattn pushed 1 commit.

ba3e199 popup: regenerate scrollbar-disappear test dumps

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Christian Brabandt

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9:10 AM (4 hours ago) 9:10 AM

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chrisbra left a comment (vim/vim#20098)

thanks

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Christian Brabandt

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9:20 AM (4 hours ago) 9:20 AM

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Closed #20098 via ba85f88.

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