pub fn plan(db: &Db, branch_name: &str) -> Result<MergePlan, Error>Expand description
Work out what merging branch would do. Writes nothing.
Purity is not a nicety here. A plan is what an operator reviews before
deciding, and a review step that mutates the thing under review changes the
answer to the question being asked. The test plan_writes_nothing holds
this to the sequence counter.