Function copy_conclusion_state 

pub fn copy_conclusion_state(
    context: &GitContext,
    cwd: &Path,
    git_dir: &Path,
    shadow: &Path,
    transaction_directory: &Path,
    ref_format: RefFormat,
) -> Result<(), GitFailure>

What: Copies every present conclusion entry of the owning worktree into the shadow and the transaction. Why: The shadow copy is what native commit reads; the transaction copy is what landing compares against.

In TS you’d write (pseudocode):

await copyConclusionState({ gitPath, cwd, gitDir, shadowPath, transactionDirectory, refFormat });