Enum FoldRecomputeCause 

pub enum FoldRecomputeCause {
    Populate,
    Edit,
}

Why crate::editor::Editor::recompute_folds_because is running, and so whether foldlevel gets to seed the folds it has not seen before.

fold-architecture.md states that foldlevel “applies as a bulk action, not a standing invariant” — apply_fold_level_to_new is the narrow exception that lets it decide the initial state of structure that shows up later. On the edit path that exception had grown back into the invariant it was carved out of: every keystroke that created a fold handed foldlevel a fold it had never seen, and at org’s foldlevel=0 that fold closed under the cursor. o on a bare headline was the purest case — a headline with no body produces no fold at all, so opening a line under it makes one appear for the very first time, mid-insert.

Variants

Populate

Content arrived from somewhere other than the user’s hands: buffer activation, a late syntax attach, an async provider batch, an LSP folding-range response. This is structure the user has genuinely not seen, so foldlevel seeds it — org opens on an overview, :set foldlevel=0 keeps collapsing a project diff whose hunks are still streaming in.

Edit

The user’s own edit reshaped the buffer. foldlevel gets no vote: a fold that exists because a keystroke just created it is not structure the user has yet to see — they are looking at it, and usually typing inside it. Emacs (#+STARTUP: overview) and vim (foldlevelstart) both treat level-driven collapse as an opening act for the same reason.

Trait Implementations

impl Clone for FoldRecomputeCause

fn clone(&self) -> FoldRecomputeCause

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for FoldRecomputeCause

impl Debug for FoldRecomputeCause

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Eq for FoldRecomputeCause

impl PartialEq for FoldRecomputeCause

fn eq(&self, other: &FoldRecomputeCause) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for FoldRecomputeCause