core/model: make diffUpdate handle reordering without duplicating rows#767
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outfoxxed merged 1 commit intoApr 27, 2026
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diffUpdate inserted an element at its target index without removing it from its previous index, so a pure permutation like [d,a,b,c] -> [a,b,c,d] left every misplaced element in the model twice and the removal pass never reclaimed them because their pointer is still in newValues. Any caller that re-sorts an existing list (dbusmenu re-layout, desktopentry re-scan) can hit this. Found via a downstream niri workspace backend where a monitor hot-plug re-sorts the model.
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diffUpdate inserted an element at its target index without removing it from its previous index, so a pure permutation like [d,a,b,c] -> [a,b,c,d] left every misplaced element in the model twice and the removal pass never reclaimed them because their pointer is still in newValues. Any caller that re-sorts an existing list (dbusmenu re-layout, desktopentry re-scan) can hit this.
I found this via a downstream niri workspace backend where a monitor hot-plug re-sorts the model: https://github.com/noctalia-dev/noctalia-qs/pull/35