zed-industries/zed · error

old_selections isn't empty

Error message

old_selections isn't empty

What it means

An internal invariant guard in select_larger_syntax_node: after expanding selections to larger syntax nodes, the code zips the last old selection with the last new one to compute autoscroll. The expect fires if old_selections is empty at that point — the function was entered without any prior selections, meaning select_larger_syntax_node ran on an editor with no selection, which the surrounding logic assumes cannot happen.

Source

Thrown at crates/editor/src/selection.rs:750

                Selection {
                    id: selection.id,
                    start: new_range.start,
                    end: new_range.end,
                    goal: SelectionGoal::None,
                    reversed: selection.reversed,
                }
            })
            .collect::<Vec<_>>();

        if !selected_larger_node {
            return; // don't put this call in the history
        }

        // scroll based on transformation done to the last selection created by the user
        let (last_old, last_new) = old_selections
            .last()
            .zip(new_selections.last().cloned())
            .expect("old_selections isn't empty");

        let is_selection_reversed = if new_selections.len() == 1 {
            let should_be_reversed = last_old.start != last_new.start;
            new_selections.last_mut().expect("checked above").reversed = should_be_reversed;
            should_be_reversed
        } else {
            last_new.reversed
        };

        self.select_syntax_node_history.disable_clearing = true;
        self.change_selections(SelectionEffects::no_scroll(), window, cx, |s| {
            s.select(new_selections.clone());
        });
        self.select_syntax_node_history.disable_clearing = false;

        let start_row = last_new.start.to_display_point(&display_map).row().0;
        let end_row = last_new.end.to_display_point(&display_map).row().0;
        let selection_height = end_row - start_row + 1;

View on GitHub (pinned to 9d272b0363)

Solutions

1. Return early if old_selections.is_empty() before the history/autoscroll step instead of unconditionally zipping
2. Skip the autoscroll computation when there is no old selection to compare against
3. Guard the action itself so it is a no-op on editors with no selections

When it happens

Trigger: Thrown at crates/editor/src/selection.rs:750 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@9d272b0363 (2026-08-20). Data as JSON: /api/errors/2874087368ca6b31. Report an issue: GitHub.