Struct Ladder 

pub struct Ladder { /* private fields */ }

What: The ladder of one invocation. Why: It carries the plan and the chosen rung from before Git to after it.

In TS you’d write (pseudocode):

type Ladder = { plan?: AddPlan; rung: Rung; slow?: SlowRoute };

Implementations

impl Ladder

pub fn first_step(&self) -> GitStep<'static>

What: The first Git run the lifecycle starts: the person’s arguments, with --no-checkout for the snapshot rung. Why: Git then validates, registers and configures the worktree, and leaves the checkout to the rung.

In TS you’d write (pseudocode):

ladder.firstStep(); // 'person' | { withoutCheckout: insertAt }

impl Ladder

pub fn finish( self, git: GitStatus, run_git: &mut GitRunner<'_>, context: &GitContext, out: &mut dyn Write, ) -> LadderResult

What: Settle the ladder after real Git returned git: serve the snapshot rung or fall back to Git’s checkout, or settle the empty subvolume of the Git rung. Why: The result carries the status the person should see and the destination whose ignored state a snapshot carried. The claim is always released: what an add left is reported when it happens, once.

In TS you’d write (pseudocode):

const result = await ladder.finish({ git, runGit, context, out });