run

type Answer struct {
	// Started is the instant the Run began, which is the instant every
	// relative predicate in it resolved against (ADR-0034). It is here
	// because §8's Refusal renders the gloss — `older_than: 14d resolved
	// to …` — and the supply for one is a Run's start and nothing else: a
	// surface with no Run renders no gloss, and a surface with one derives
	// it rather than reading a member no file holds.
	Started time.Time
	// Run is the Run's id, and Identified says an entry was written under
	// it. The pair is §8's *where no entry was written the id is absent, and
	// its absence is the fact*: two paths decline before a Run is identified
	// at all, and on both the terminal line names nothing to look up.
	Run        store.RunID
	Identified bool
	// Outcome is §12's triple, and every Run reaching this package ends in
	// exactly one member of it.
	Outcome store.Outcome
	// Steps is one entry per Step that reached a Disposition, in the Run's
	// written order — which is the Step table's order and the `<nnnn>` the
	// entry names its files by (§8, §12).
	Steps []Step
	// Withheld is the position of the Step a rehearsal stopped at, and zero
	// where the Run withheld nothing — which is every Run that is not a
	// `--dry-run`, and every rehearsal that reached the end of a Procedure
	// with no effectful Step in it (§9, ADR-0010).
	//
	// It is the position and not a Disposition of its own, because §12's
	// seven are closed and the withheld Step is one of them: the Run ended
	// before it, it wrote no file, and *never reached* is what an entry
	// reads back from that silence (§7). What this carries is *it stopped,
	// and here is where* — which the entry holds as the first Step of the
	// run of silent ones and the surface would otherwise have to re-derive.
	//
	// **Every surface reads it from here**, through Withholds below: the
	// page's sentence beneath the Step table, and the `withheld` member on
	// that Step's row, which is what carries the same fact to `--json` and
	// to MCP (§8, §9, ADR-0091, issue #206).
	Withheld int
	// Provenance is the Run-wide half: what `run.json` carries, and what the
	// Run-wide `provenance` row renders (§7, §8, ADR-0043).
	Provenance store.RunProvenance
	// Refusal is the checks that declined, in the order `check` prints them,
	// and is non-empty exactly where Outcome is OutcomeRefused. It is one
	// array and never several Refusals: a Run has at most one Refusal ever,
	// the outcome being terminal, and the members are the checks one phase
	// evaluated together (§7, §8, ADR-0061).
	//
	// What the terminal line and the `outcome` row name is the **first**
	// member's `error_code`, derived where it is rendered and stored nowhere
	// (§7, §8).
	Refusal []Refusal
	// Fault is what stopped the Run, and nil where nothing did. It is
	// narration's — a failure carries no `error_code` (§9, §12) — and it is
	// the whole of what the surface has to say about a `failed` Run beyond
	// the outcome itself.
	Fault error
}

type Narrator interface {
	// Began is the Run naming itself, before its first Step. It is the one
	// place a Run's identity reaches an operator whose process is killed
	// outright, which is why it is narrated rather than left to the
	// terminal line (§9).
	//
	// A surface where that is not the one place sends nothing, which is a
	// rendering like any other: a Narrator decides what an event says, and
	// saying nothing is one of the answers.
	Began(run store.RunID)
	// Uncommitted is the Run saying the code it is about to perform is in
	// no commit: an artefact it read differs from `HEAD` or is untracked,
	// which is the same fact `repo_dirty` marks on the entry (§7).
	//
	// It fires **before the first Step** and where that fact stands, and
	// nowhere else. What it costs is what the entry cannot say for itself
	// in time: every revision this Run is about to record is a blob id
	// nothing ever wrote, so a later `review` of any of those artefacts
	// opens at nothing and the Comparison's baseline is gone (§8,
	// ADR-0119, issue #239).
	Uncommitted()
	// Reached is one Step boundary: the Step's position, how many the Run
	// holds, and its authored id.
	Reached(position, of int, id string)
}

type Narrowing struct {
	// Line is where the operand is authored and Field its path in §8's
	// remediation notation. They are the predicate's own coordinate rather
	// than the Bound's: the two rows of `EDIT ONE OF` are two edits, and
	// they are on different lines.
	Line  int
	Field string
	// From is the operand as authored and To the rung proposed.
	From, To string
	// Expansion is what the proposal resolved to — the count the page
	// carries, and the whole reason this read was performed.
	Expansion int
}

type Refusal struct {
	store.RefusalMember
	// Operation and Target are the binding of the Step this check cites,
	// and are empty on a Refusal that cites no Step.
	Operation, Target string
	// Narrowed is the second remediation §8's `EDIT ONE OF` table renders
	// beside a Bound, and nil on every check that has no second edit to
	// offer — which is every one of them but `bound-exceeded`, and that one
	// only where its selector carries an operand a rung can be proposed for
	// (§8, narrow.go).
	//
	// It rides here rather than in the entry for the reason `resolved` rides
	// on a row: it is derived, it is a hypothetical, and a Store holding one
	// would be a Store holding a count no Run ever acted on (§7, ADR-0034).
	Narrowed *Narrowing
}

type Request struct {
	// Repository is the load every name in the Run resolves against, and
	// RepoRoot is where it was read from — the second being what the code
	// branch's revisions are read out of.
	Repository repository.Loaded
	RepoRoot   string
	// Store is the record, already located. Locating it is the caller's,
	// because a Run that cannot find one Refuses `store-absent` before it
	// has an id to refuse under (§6, §7).
	Store *store.Store
	// Procedure is the top-level Procedure's name, already resolved against
	// the repository: a positional matching nothing is a usage error and
	// never reaches here (§9, ADR-0060).
	Procedure string
	// Trigger is what caused this Run and where it happened, already read
	// off the environment. It is filled rather than derived here for the
	// reason this package reads no environment variable at all — and
	// nothing in the engine reads it back, recording where a Run happened
	// being a fact about the occasion rather than an authority axis (§5,
	// §7).
	Trigger store.Trigger
	// DryRun says this Run is a rehearsal. It is carried into the entry on
	// every Run, false included (§7, ADR-0001).
	//
	// **A rehearsal performs the reads it reaches and stops at the first
	// effectful Step** rather than simulating one (§9, ADR-0010). Nothing
	// about that Step is simulated, predicted or described: `hyper` has no
	// plan, and a surface saying what a `mutate` *would* do would be the
	// prospective counterpart the Comparison deliberately is not. The stop
	// is Perform's, and Withheld on the Answer is the Step it stopped at
	// (issue #155).
	//
	// The places the marker is read back are already built, and both read
	// it off an **entry** rather than off this member: an entry a rehearsal
	// wrote is evidence that a rehearsal happened and evidence of nothing
	// else, so a Step's identity digest filters it out (step.go) and so does
	// run-once Repeatability (once.go). Getting the second wrong is what the
	// exception to the absence rule is bought against — a rehearsal counted
	// as evidence would permanently refuse every run-once Step in the
	// Procedure it rehearsed (§7, §8, ADR-0001).
	DryRun bool
	// Version is the binary's, and it is Provenance's `hyper_version`. It is
	// always a release string: the pin gate refuses any binary whose version
	// differs from the repository's in either direction, so there is no
	// development form to write (§7, §11).
	Version string
	// Now is the clock. Every instant the Run records comes through it, so a
	// fixture's entry is reproducible and the dates a golden holds are the
	// case's own.
	Now func() time.Time
	// Mint mints the Run id at the instant it is handed. It is threaded
	// rather than called for the reason the clock is, and one more: a Run id
	// lands on the terminal line, in the `outcome` row, in `run.json` and in
	// every Store path a Run writes, so an id minted here would make every
	// golden of a Run unassertable (§8, ADR-0047).
	Mint func(now time.Time) store.RunID
	// LookupEnv is the environment, read. It is threaded for the reason the
	// clock is — the engine reaches no process fact of its own — and it is
	// reached exactly once per credential slot the Run's bindings require,
	// at the credential pass §6 puts before Step 1 (§6, ADR-0007).
	//
	// It answers a value **and whether the variable is set at all**, which
	// is os.LookupEnv's shape rather than os.Getenv's: presence is the whole
	// of what the gate asks, and a variable set to the empty string is
	// present (§9).
	LookupEnv func(string) (string, bool)
	// Environ is the environment read whole, and it is reached for exactly
	// one thing: a `shell` Operation's child inherits it, less every
	// credential-slot variable in the repository (§3, §11, issue #142).
	//
	// It is a second read of one subject rather than a widening of the
	// first. LookupEnv answers *what does this name hold*, which is the
	// whole of what the credential pass asks; composing a child's
	// environment is a subtraction, and a set of names nothing enumerates is
	// not a set anything can subtract from.
	Environ func() []string
	// SecretSink is the path `--secret-out` named, and "" where the
	// invocation supplied none. It is the **occasion's** supply rather than
	// the environment's or the artefacts', which is why it arrives here
	// beside DryRun rather than being read off anything (§6, §9, ADR-0008).
	//
	// The engine reads its presence and never its value: what a Run does
	// with a sink is the milestone that writes one's, and #133 flags the ADR
	// that has to state the file's format first.
	SecretSink string
	// Dial and Exec are the two Capabilities' performers. Neither is reached
	// for: internal/capability is handed one, so a case exercises a real
	// handshake against a server standing in the test process and a real
	// child against a script a fixture checked in (§5, issues #133, #142).
	Dial capability.Dial
	Exec capability.Exec
	// Interrupted says the first interrupt has arrived, and it is the whole
	// of what this package knows about signals: which signals are watched
	// for, what they exit with and when a second one kills the process are
	// the surface's, one package up (§6, §9, ADR-0015, issue #145).
	//
	// It is a function for the reason every other process read here is one
	// — the engine reaches no process fact of its own — and it answers
	// rather than blocks, because the one question a Run asks about a stop
	// is *has one arrived by now*: it is asked where the next Step would
	// start and nowhere else, so a Step in flight is never asked to stop
	// and never told to (Perform).
	//
	// **Being a predicate rather than a signal is what let a second surface
	// arrive without a second mechanism.** A `run` reached through the MCP
	// server has no terminal behind it and catches no signal at all; what
	// stops it is the client cancelling the request, and the mapping is
	// this predicate reading that call's context. The composition of the
	// two is the surface's, one package up, and nothing here can tell which
	// of them answered (§6, §9, ADR-0015, ADR-0092, cli.stopping).
	//
	// It may be nil, which is a Run nobody can stop: a `hyper` compiled
	// into a test binary has no handler installed and no call to cancel.
	Interrupted func() bool
	// Narrator is where progress goes as it happens. It may be nil, which is
	// a Run nobody is watching.
	Narrator Narrator
}

type Step struct {
	// Position is the Step's place in the Run's written order, the first
	// Step 1.
	Position int
	// ID is the Step's authored `id:`, Kind its Operation's declared Kind
	// held rather than resolved, and Disposition what became of it (§7).
	ID          string
	Kind        store.Kind
	Disposition store.Disposition
	// Path is the invocation chain this Step was reached through, and empty
	// on a top-level Step. It is the same member the Step file carries, and
	// it is what the Step table renders a nested Step under (§7, §8).
	Path string
	// Records is the size of the identity set — what the Step concluded
	// about, and never the versions it wrote (ADR-0030) — and Concluded says
	// a set exists at all. Three of §12's seven Dispositions conclude about
	// nothing, and the dash that renders for them is what tells them from
	// the *ran* Step whose set is written empty (§8).
	Records   int
	Concluded bool
	// Expanded is how many Record identities the Step's calls **reached**,
	// and it is written **only where the Step stopped short of them** — a
	// `read` Expansion that drained and then halted (§6). It is what
	// `n of m` is read against: `n` is Records and `m` is this, and the
	// Records between them are the ones unaccounted for (§7, §8, issue
	// #140). A Step carrying no `over:` resolved no selector and makes its
	// call under a set of one, so a halted one is `0 of 1`.
	//
	// It counts Records and never the Expansion's members, which are the
	// same number only where an Operation projects one Record per member.
	// A `series` response whose tenth member's identity path did not resolve
	// is one member of an Expansion and ten Records reached, and the column
	// reads `9 of 10` — the entry says expanded to one beside it,
	// `expanded_to` being what the *selector* resolved to and this being
	// what the answers held (issue #144).
	//
	// Zero is *nothing stood short*, which is every Step that accounted for
	// everything it reached. It is written from the drain rather than
	// derived from Records, because *unaccounted for* is a fact about
	// Records that were never concluded about and the two counts are equal
	// for other reasons too — an identity two members resolve to is one
	// member of the set and two Records reached, which is a collision §6
	// halts on rather than a Step that stopped short (ADR-0070, ADR-0072).
	//
	// It is a count and never the names. Which Records are unaccounted for
	// is `expanded_to`'s and nowhere else, and a Step value carrying them
	// would be the second place a surface could read them from (§7, §8).
	Expanded int
	// Provenance is the Step's half: what the Step file carries, and what
	// that Step's `provenance` row renders (§7, ADR-0043).
	Provenance store.StepProvenance
}