Changes touching this path

• a revset is accepted wherever a selector is, through the door that already existed - and the verb population is DERIVED from the shipped help text rather than from the dispatch table, which closes the two-spellings trap that had already cost two tickets UPSTREAM of this change, since help is pinned set-equal to the table in both directions. a placeholder-name list could undercount a DIFFERENT way, so the whole placeholder vocabulary of the help text is a SECOND set-equality: a verb spelling its change argument some new way now reddens the build instead of dropping silently out of the population. twenty-five selector-taking verbs, TWO of which a hand list would have missed and the derivation found - diff spells from and to, merge spells head, and neither says selector. four are adopted here, exactly the four #1563 named, all through the existing door via one shared consumer: no second parser and no per-verb precedence, because two verbs disagreeing about what a bare word means is worse than neither having revsets. the point-versus-set question is decided PER VERB with its reason rather than made uniform. cat is a point because its product is one path bytes written verbatim with no frame around them, so two versions arrive concatenated and indistinguishable from one file containing both. archive is a point because N trees are either N files, which is a different verb, or one file whose members collide path-for-path. blame is a point because the lineage walk STARTS there and there is no column for a second start. and ignore-rev is a SET USED WHOLE, because the only use of its result is a membership test, so every member is taken. diff is the interesting refusal: a two-member set does NOT collapse into the pair, because the pair is already spelled as the two arguments, so collapsing would give one argument an arity decided by data the operator cannot see - the same expression a comparison on one repo and a refusal on another - and a set has no SIDES, so a topological order would silently come to mean oldest-versus-newest. that is rejected explicitly and recorded rather than overlooked. the shared rule is exactly one, else REFUSE naming the count, and the door never takes a member. sixteen verbs are left, in two groups, both NAMED in the census rather than merely absent: nine where a set is a fan-out over a REWRITE, needing an order, a per-change failure rule, an undo story and a confirmation surface that do not exist - guessing on a destructive verb being the worst place to guess - and seven that are points by nature and left on scope, two of which have a coherent set arm and so are decisions rather than transcriptions. every pin RUNS THE VERB against a real three-change repo, each row in its own fresh copy with declared setup, so a refusal that fires BEFORE the selector resolves cannot pass vacuously - which is the exact failure this ticket exists downstream of, a criterion once pinned only at the flag gate. ten mutations with counts read. the control that matters is the one dropping a placeholder: the VERB census stayed GREEN, because diff line also spells another, while only the vocabulary census fired - which is what makes that second guard load-bearing rather than decorative. and the ignore-rev pin carries its own control, because without it the equality would hold just as well between two no-ops. three prose claims this change made FALSE are fixed, and one existing pin was MOVED rather than deleted, onto a verb the census names as selector-only so the choice cannot go stale silently (#1689) 5e9b9cb6 · dbf3dbe6…

Renames are not followed. loot's tree maps a path to an address, so a rename is a delete and an add. This list is the history of the name, not of the bytes.