use crate::compile::{Category as C, Refusal, Shortfall, ShortfallReason as S};
use crate::expr::{StepTy, TyEnv};
use crate::template as t;
use crate::value::{Ty, Value};
use rustev_contract::definition::{
ArtifactPin, BindingChoice, Definition, ExcessPolicy, ItemSource, Operation, OutcomeDecl,
ParamSource, ProvenanceClass, RequiredKind, StepBody,
};
use rustev_contract::descriptor::{BackendDescriptor, OutputKind};
use rustev_contract::execution::ExecutionPolicy;
use rustev_contract::generation::*;
use rustev_contract::judgment::Derivation;
use rustev_contract::plan::PlanStepDetail;
use rustev_contract::{Document, Identified, schema};
use std::collections::{BTreeMap, BTreeSet};
fn error(category: C, id: &str, detail: impl ToString) -> Refusal {
Refusal {
category,
subject: format!("step:{id}"),
detail: detail.to_string(),
shortfalls: vec![],
}
}
fn name(s: &str) -> bool {
rustev_contract::parameter::is_parameter_name(s)
}
fn last(r: &str) -> &str {
r.rsplit(['/', ':']).next().unwrap_or(r)
}
pub(crate) fn matching<'a>(
g: &Generate,
def: &'a Definition,
) -> Vec<&'a Vec<rustev_contract::definition::ParamDecl>> {
def.policy
.rules
.iter()
.filter_map(|r| match &r.then {
OutcomeDecl::Propose { action, params }
if match &g.when {
GenerateWhen::AnyPropose => true,
GenerateWhen::Actions(a) => a.contains(action),
} =>
{
Some(params)
}
_ => None,
})
.collect()
}
pub(crate) fn isolation(
def: &Definition,
execution: Option<&ExecutionPolicy>,
) -> Result<(), Refusal> {
let ids: BTreeSet<_> = def
.steps
.iter()
.filter(|s| matches!(s.body, StepBody::Generate(_)))
.map(|s| s.id.as_str())
.collect();
fn walk(v: &serde_json::Value, key: &str, ids: &BTreeSet<&str>) -> Option<String> {
match v {
serde_json::Value::String(s) => {
let target = s
.strip_prefix("step:")
.map(|s| s.split('/').next().unwrap_or(s));
if target.is_some_and(|s| ids.contains(s))
|| (matches!(key, "step" | "target") && ids.contains(s.as_str()))
{
Some(s.clone())
} else {
None
}
}
serde_json::Value::Array(a) => a.iter().find_map(|v| walk(v, key, ids)),
serde_json::Value::Object(m) => m
.iter()
.filter(|(k, _)| {
!matches!(
k.as_str(),
"literal"
| "lit"
| "text"
| "instructions"
| "question"
| "task"
| "reason"
| "options"
| "vocabularies"
| "id"
| "name"
| "action"
| "actions"
| "language"
| "locale"
| "digest"
| "backend"
)
})
.find_map(|(k, v)| walk(v, k, ids)),
_ => None,
}
}
if ids.is_empty() {
return Ok(());
}
for s in &def.steps {
if let Some(r) = walk(
&serde_json::to_value(&s.body).expect("step serialization"),
"",
&ids,
) {
return Err(error(
C::ModelOutputFlow,
&s.id,
format!("generated value {r} is not readable"),
));
}
}
let mut document = serde_json::to_value(def).expect("definition serialization");
document.as_object_mut().unwrap().remove("steps");
if let Some(r) = walk(&document, "", &ids) {
return Err(error(C::ModelOutputFlow, "policy", r));
}
if let Some(e) = execution {
let mut v = serde_json::to_value(e).expect("execution serialization");
if let Some(entries) = v["steps"].as_array_mut() {
for entry in entries {
entry.as_object_mut().unwrap().remove("step");
}
}
if let Some(r) = walk(&v, "", &ids) {
return Err(error(C::ModelOutputFlow, "execution", r));
}
}
Ok(())
}
pub(crate) fn structure(def: &Definition) -> Result<(), Refusal> {
let count = def
.steps
.iter()
.filter(|s| matches!(s.body, StepBody::Generate(_)))
.count();
if count > 8 {
return Err(error(
C::InvalidGeneration,
"definition",
"more than eight generate steps",
));
}
for s in &def.steps {
let StepBody::Generate(g) = &s.body else {
continue;
};
let bad = |detail: String| error(C::InvalidGeneration, &s.id, detail);
let template: BTreeSet<&String> = g
.template
.params
.values()
.filter_map(|b| match b {
TemplateBinding::Reference(r) => Some(r),
_ => None,
})
.collect();
for r in dependencies(g, def) {
if let Some(id) = r
.strip_prefix("step:")
.map(|r| r.split('/').next().unwrap())
&& !def.steps.iter().any(|s| s.id == id)
{
let category = if template.contains(&r) {
C::Template
} else {
C::InvalidGeneration
};
return Err(error(category, &s.id, format!("unknown step {id}")));
}
}
serde_json::from_value::<Generate>(serde_json::to_value(g).unwrap())
.map_err(|e| error(C::Parse, &s.id, e))?;
if let GenerateWhen::Actions(actions) = &g.when {
for a in actions {
if !def
.policy
.rules
.iter()
.any(|r| matches!(&r.then, OutcomeDecl::Propose { action, .. } if action == a))
{
return Err(bad(format!("when action {a} is not proposed")));
}
}
}
if let ModelForEach::List(f) = &g.for_each {
if !name(&f.bind)
|| ["input", "step", "proposal", "param", "this"].contains(&f.bind.as_str())
{
return Err(bad(format!("invalid bind {}", f.bind)));
}
if let Some(id) = f.over.strip_prefix("step:") {
if !def
.steps
.iter()
.any(|s| s.id == id && matches!(s.body, StepBody::Exact(_)))
{
return Err(bad(format!("{} must name an exact id-list step", f.over)));
}
} else if !f.over.starts_with("proposal:") {
return Err(bad("for_each.over must name proposal or exact step".into()));
}
}
let mut owned: BTreeSet<&str> = def.inputs.iter().map(|i| i.name.as_str()).collect();
owned.extend(def.steps.iter().map(|s| s.id.as_str()));
for rule in &def.policy.rules {
if let OutcomeDecl::Propose { params, .. } = &rule.then {
owned.extend(params.iter().map(|p| p.name.as_str()));
}
}
owned.extend(g.projection.iter().map(|r| last(r)));
let mut carried = BTreeSet::new();
for r in &g.carry {
if !carried.insert(last(r)) {
return Err(bad(format!("duplicate carried name {}", last(r))));
}
owned.insert(last(r));
}
for f in &g.output.fields {
if owned.contains(f.name.as_str()) {
return Err(bad(format!("field {} collides with context", f.name)));
}
if f.required && !g.backstop.fields.contains_key(&f.name) {
return Err(bad(format!("required field {} has no backstop", f.name)));
}
if let GeneratedType::List { vocabulary, .. } = &f.ty
&& !g.vocabularies.contains_key(vocabulary)
{
return Err(bad(format!("unknown vocabulary {vocabulary}")));
}
}
for (n, b) in &g.backstop.fields {
if !g.output.fields.iter().any(|f| {
&f.name == n
&& matches!(
(&f.ty, b),
(GeneratedType::Text { .. }, BackstopField::Text(_))
| (GeneratedType::List { .. }, BackstopField::List(_))
)
}) {
return Err(bad(format!(
"backstop {n} is undeclared or has the wrong form"
)));
}
}
}
Ok(())
}
pub(crate) fn resolve(
def: &Definition,
supplied: &[PromptTemplate],
) -> Result<BTreeMap<String, PromptTemplate>, Refusal> {
let mut out = BTreeMap::new();
let mut distinct = BTreeSet::new();
for s in &def.steps {
let template = match &s.body {
StepBody::Generate(g) => &g.template,
StepBody::Extract(e) => &e.template,
_ => continue,
};
let candidates: Vec<_> = supplied.iter().filter(|t| t.id == template.id).collect();
let Some(p) = candidates
.iter()
.find(|p| p.id().ok().as_ref() == Some(&template.digest))
else {
return Err(error(
C::Template,
&s.id,
"prompt template missing or identity differs",
));
};
if candidates
.iter()
.any(|other| other.id().ok() != p.id().ok())
{
return Err(error(
C::Template,
&s.id,
"conflicting supplied template identities",
));
}
PromptTemplate::parse(&p.canonical().map_err(|e| error(C::Parse, &s.id, e))?)
.map_err(|e| error(C::Parse, &s.id, e))?;
if p.schema != schema::PROMPT_TEMPLATE {
return Err(error(C::Template, &s.id, "wrong template schema"));
}
distinct.insert(template.digest.clone());
if distinct.len() > 16 {
return Err(error(
C::InvalidGeneration,
&s.id,
"more than sixteen templates",
));
}
if p.params.len() != template.params.len()
|| p.params
.iter()
.any(|p| !template.params.contains_key(&p.name))
{
return Err(error(
C::Template,
&s.id,
"missing or extra template parameters",
));
}
out.insert(s.id.clone(), (**p).clone());
}
Ok(out)
}
pub(crate) fn dependencies(g: &Generate, def: &Definition) -> Vec<String> {
let mut refs: Vec<_> = g.projection.iter().chain(&g.carry).cloned().collect();
refs.extend(g.template.params.values().filter_map(|b| match b {
TemplateBinding::Reference(r) => Some(r.clone()),
_ => None,
}));
if let ModelForEach::List(f) = &g.for_each {
refs.push(f.over.clone());
if let ItemSource::List { list, .. } = &f.items {
refs.push(list.clone());
}
}
for params in matching(g, def) {
for p in params {
if let ParamSource::Ref(r) = &p.value {
refs.push(r.clone());
}
}
}
refs.extend(
def.steps
.iter()
.filter(|s| !matches!(s.body, StepBody::Generate(_)))
.map(|s| format!("step:{}", s.id)),
);
refs.retain(|r| r.starts_with("input:") || r.starts_with("step:"));
refs
}
pub(crate) fn field(ty: &Ty, class: t::Class) -> Option<t::Field> {
let kind = match ty {
Ty::Bool => t::Type::Bool,
Ty::Integer => t::Type::Integer,
Ty::Decimal => t::Type::Decimal,
Ty::Text { max_bytes } => t::Type::Text {
max_bytes: (*max_bytes).try_into().ok()?,
},
Ty::Enum(o) => t::Type::Enum(o.clone()),
Ty::Timestamp => t::Type::Timestamp,
Ty::Maybe(v) | Ty::Nullable(v) => t::Type::Maybe(Box::new(field(v, class)?)),
Ty::List { item, max } => t::Type::List {
element: Box::new(field(item, class)?),
max_items: (*max).try_into().ok()?,
},
Ty::Filtered { max, id_bytes } | Ty::Shortlist { max, id_bytes } => t::Type::List {
element: Box::new(t::Field {
kind: t::Type::Text {
max_bytes: *id_bytes as usize,
},
class,
}),
max_items: *max as usize,
},
Ty::Record(fs) => t::Type::Record(
fs.iter()
.filter_map(|(n, t)| field(t, class).map(|f| (n.clone(), f)))
.collect(),
),
_ => return None,
};
Some(t::Field { kind, class })
}
fn class(d: Derivation) -> t::Class {
match d {
Derivation::ExactDerived => t::Class::Exact,
Derivation::ModelDerived => t::Class::Model,
Derivation::MixedDerived => t::Class::Mixed,
}
}
fn path(root: &t::Field, parts: &[&str]) -> Result<t::Field, String> {
let mut f = root.clone();
for p in parts {
let t::Type::Record(fields) = &f.kind else {
return Err("path does not traverse a record".into());
};
f = fields
.get(*p)
.cloned()
.ok_or_else(|| format!("unknown field {p}"))?;
}
Ok(f)
}
fn reference(r: &str, roots: &t::Schema) -> Result<t::Field, String> {
let (root, tail) = r.split_once(':').ok_or("reference needs a kind")?;
let mut parts = tail.split('/');
let first = parts.next().ok_or("empty reference")?;
let (f, rest): (_, Vec<_>) = if root == "bind" {
(roots.get(first).ok_or("unknown bind")?, parts.collect())
} else {
(
roots.get(root).ok_or("unknown reference root")?,
std::iter::once(first).chain(parts).collect(),
)
};
path(f, &rest)
}
pub(crate) fn param_type(p: &PromptParamType) -> t::Type {
match p {
PromptParamType::Bool => t::Type::Bool,
PromptParamType::Integer => t::Type::Integer,
PromptParamType::Decimal => t::Type::Decimal,
PromptParamType::Text { max_bytes } => t::Type::Text {
max_bytes: *max_bytes as usize,
},
PromptParamType::Enum { options } => t::Type::Enum(options.clone()),
}
}
#[derive(Debug, Clone)]
pub(crate) struct Checked {
pub binding: GenerateBinding,
pub output_bytes: u64,
pub prompt: Option<t::Template>,
pub backstops: BTreeMap<String, t::Template>,
}
pub(crate) fn type_check(
def: &Definition,
prompts: &BTreeMap<String, PromptTemplate>,
inputs: &BTreeMap<String, Ty>,
steps: &BTreeMap<String, StepTy>,
derivations: &BTreeMap<String, Derivation>,
_deps: &BTreeMap<String, Vec<String>>,
) -> Result<BTreeMap<String, Checked>, Refusal> {
let mut checked = BTreeMap::new();
let env = TyEnv {
inputs,
steps,
item: None,
v2: true,
};
for s in &def.steps {
let StepBody::Generate(g) = &s.body else {
continue;
};
let bad = |d: String| error(C::Template, &s.id, d);
let template_error = |e: t::Error| {
error(
if matches!(e, t::Error::ModelOutputFlow(_)) {
C::ModelOutputFlow
} else {
C::Template
},
&s.id,
e,
)
};
let mut roots = t::Schema::new();
roots.insert(
"input".into(),
t::Field::exact(t::Type::Record(
def.inputs
.iter()
.filter_map(|i| {
field(
&inputs[&i.name],
if i.provenance.contains(&ProvenanceClass::ModelDerived) {
t::Class::Mixed
} else {
t::Class::Exact
},
)
.map(|f| (i.name.clone(), f))
})
.collect(),
)),
);
let mut step_fields = BTreeMap::new();
for step in &def.steps {
let f = match steps.get(&step.id) {
Some(StepTy::Exact(ty)) => field(ty, class(derivations[&step.id])),
Some(StepTy::Semantic(..)) => Some(t::Field {
kind: t::Type::Bool,
class: t::Class::Model,
}),
None if matches!(step.body, StepBody::Generate(_)) => Some(t::Field {
kind: t::Type::Bool,
class: t::Class::Generated,
}),
_ => None,
};
if let Some(f) = f {
step_fields.insert(step.id.clone(), f);
}
}
roots.insert("step".into(), t::Field::exact(t::Type::Record(step_fields)));
let proposals = matching(g, def);
let mut common = BTreeMap::new();
if let Some(first) = proposals.first() {
for p in *first {
let resolve = |v: &ParamSource| -> Result<t::Field, String> {
match v {
ParamSource::Ref(r) => reference(r, &roots),
ParamSource::Lit(l) => field(&Value::literal_ty(l), t::Class::Exact)
.ok_or("unsupported proposal type".into()),
}
};
let Ok(f) = resolve(&p.value) else { continue };
if proposals.iter().all(|ps| {
ps.iter()
.find(|x| x.name == p.name)
.is_some_and(|x| resolve(&x.value).ok().as_ref() == Some(&f))
}) {
common.insert(p.name.clone(), f);
}
}
}
roots.insert("proposal".into(), t::Field::exact(t::Type::Record(common)));
let mut max_items = 1;
let mut bind = None;
if let ModelForEach::List(f) = &g.for_each {
max_items = match f.max_items {
ModelBound::Literal(n) => n,
_ => return Err(bad("unresolved max_items parameter".into())),
};
let valid = if f.over.starts_with("proposal:") {
matches!(reference(&f.over,&roots).map(|f|f.kind),Ok(t::Type::List {element,..}) if matches!(element.kind,t::Type::Text{..}|t::Type::Enum(_)))
} else {
crate::expr::ref_ty(&f.over, &env).ok().is_some_and(|ty| {
!matches!(ty, Ty::Ranking { .. }) && Value::id_bounds(&ty).is_some()
})
};
let exact = reference(&f.over, &roots).is_ok_and(|v| v.class == t::Class::Exact);
if !valid || !exact {
return Err(error(
C::InvalidGeneration,
&s.id,
"for_each.over must yield an id list, filter or shortlist in every matching outcome",
));
}
if let ItemSource::List { list, id_field } = &f.items {
let source = reference(list, &roots).map_err(bad)?;
let t::Type::List { element, .. } = source.kind else {
return Err(bad("items source must be a list".into()));
};
if !matches!(
path(&element, &[id_field]).map(|f| f.kind),
Ok(t::Type::Text { .. } | t::Type::Enum(_))
) {
return Err(bad("item id field must be text or enum".into()));
}
roots.insert(f.bind.clone(), *element);
}
bind = Some(f.bind.clone());
}
for r in &g.carry {
if reference(r, &roots).map_err(bad)?.class != t::Class::Exact {
return Err(error(
C::InvalidGeneration,
&s.id,
format!("carry {r} is not exact-derived"),
));
}
}
let p = &prompts[&s.id];
let mut params = BTreeMap::new();
for param in &p.params {
let ty = param_type(¶m.ty);
let (f, source) = match &g.template.params[¶m.name] {
TemplateBinding::Reference(r) => (
reference(r, &roots).map_err(bad)?,
t::BindingSource::ExactReference,
),
TemplateBinding::Literal { literal } => (
field(&Value::literal_ty(literal), t::Class::Exact)
.ok_or_else(|| bad("unsupported literal".into()))?,
t::BindingSource::Literal,
),
TemplateBinding::Parameter(_) => {
return Err(bad("unresolved prompt parameter".into()));
}
};
if f.class != t::Class::Exact {
return Err(error(
C::ModelOutputFlow,
&s.id,
"template parameter is model-derived",
));
}
t::parameter_binding(&ty, &f, source).map_err(template_error)?;
params.insert(param.name.clone(), t::Field::exact(ty));
}
let prompt = t::Template::compile(
&p.instructions,
[("param".into(), t::Field::exact(t::Type::Record(params)))].into(),
t::Options::prompt(),
)
.map_err(template_error)?;
let mut vocabularies = BTreeMap::new();
for (n, v) in &g.vocabularies {
let Vocabulary::Literal(options) = v else {
return Err(bad("unresolved vocabulary".into()));
};
t::list_backstop(&[], options, 1, false).map_err(template_error)?;
vocabularies.insert(n.clone(), options.clone());
}
let mut output_bytes = 0u64;
let mut backstops = BTreeMap::new();
for f in &g.output.fields {
let b = g.backstop.fields.get(&f.name);
match &f.ty {
GeneratedType::Text { max_bytes, lines } => {
output_bytes = output_bytes.saturating_add(*max_bytes);
if let Some(BackstopField::Text(source)) = b {
let template = t::Template::compile(
source,
roots.clone(),
t::Options {
mode: t::Mode::Backstop { bind: bind.clone() },
locale: t::Locale::parse(&g.backstop.locale)
.map_err(template_error)?,
escape: match g.backstop.escape {
Escape::Text => t::Escape::Text,
Escape::Html => t::Escape::Html,
},
overflow: match g.backstop.overflow {
Overflow::Refuse => t::Overflow::Refuse,
Overflow::Truncate => t::Overflow::Truncate,
},
lines: match lines {
Lines::Single => t::Lines::Single,
Lines::Multi => t::Lines::Multi,
},
max_bytes: *max_bytes as usize,
required: f.required,
},
)
.map_err(template_error)?;
backstops.insert(f.name.clone(), template);
}
}
GeneratedType::List {
vocabulary,
max_items,
} => {
let options = &vocabularies[vocabulary];
output_bytes =
output_bytes.saturating_add(max_items.saturating_mul(
options.iter().map(|s| s.len() as u64).max().unwrap_or(0),
));
if let Some(BackstopField::List(items)) = b {
t::list_backstop(items, options, *max_items as usize, f.required)
.map_err(template_error)?;
}
}
}
}
let mut projection_bytes = 2u64;
for r in &g.projection {
let bytes = if r.starts_with("input:") || r.starts_with("step:") {
crate::expr::ref_ty(r, &env).map_err(bad)?.max_json_bytes()
} else {
field_bytes(&reference(r, &roots).map_err(bad)?.kind)
};
projection_bytes = projection_bytes
.saturating_add(6 * r.len() as u64 + 4)
.saturating_add(bytes);
}
let k = if matches!(g.screen.output, ScreenOutput::Screener { .. }) {
g.output
.fields
.iter()
.filter(|f| matches!(f.ty, GeneratedType::Text { .. }))
.count() as u64
} else {
0
};
checked.insert(
s.id.clone(),
Checked {
output_bytes,
prompt: Some(prompt),
backstops,
binding: GenerateBinding {
output_screener: None,
template_id: g.template.digest.clone(),
template: p.clone(),
helpers_version: t::HELPERS.into(),
backend_id: String::new(),
artifact: rustev_contract::ids::ArtifactId::parse(&format!(
"sha256:{}",
"0".repeat(64)
))
.unwrap(),
descriptor: rustev_contract::ids::DescriptorId::parse(&format!(
"sha256:{}",
"0".repeat(64)
))
.unwrap(),
output: g.output.clone(),
vocabularies,
max_items,
worst_case_requests: max_items.saturating_mul(1 + g.repair.max_attempts + k),
worst_case_projection_bytes: projection_bytes,
},
},
);
}
Ok(checked)
}
fn field_bytes(ty: &t::Type) -> u64 {
match ty {
t::Type::Bool => 5,
t::Type::Integer => 20,
t::Type::Decimal => 44,
t::Type::Timestamp => 26,
t::Type::Text { max_bytes } => 2u64.saturating_add(6u64.saturating_mul(*max_bytes as u64)),
t::Type::Enum(o) => 2 + 6 * o.iter().map(String::len).max().unwrap_or(0) as u64,
t::Type::Maybe(f) => field_bytes(&f.kind).max(4),
t::Type::List { element, max_items } => {
2u64.saturating_add((*max_items as u64).saturating_mul(1 + field_bytes(&element.kind)))
}
t::Type::Record(fs) => fs.iter().fold(2u64, |n, (k, f)| {
n.saturating_add(6 * k.len() as u64 + 4)
.saturating_add(field_bytes(&f.kind))
}),
}
}
pub(crate) fn candidate(
g: &Generate,
c: &Checked,
b: &BackendDescriptor,
) -> Result<OutputKind, Vec<S>> {
let mut reasons = vec![];
let ops: Vec<_> = b
.operations
.iter()
.filter(|o| o.operation == Operation::Generate)
.collect();
let chosen = ops
.iter()
.find(|o| matches!(o.output, OutputKind::TextRecord { .. }));
match chosen {
Some(o) => {
if o.max_options < g.output.fields.len() as u64 {
reasons.push(S::Options {
max: o.max_options,
needed: g.output.fields.len() as u64,
});
}
if let OutputKind::TextRecord {
max_output_bytes,
languages,
..
} = &o.output
{
if *max_output_bytes < c.output_bytes {
reasons.push(S::OutputLimit {
max: *max_output_bytes,
needed: c.output_bytes,
});
}
if let Language::Literal(l) = &g.language
&& !languages.contains(l)
{
reasons.push(S::Language {
required: l.clone(),
});
}
}
}
None => {
if let Some(o) = ops.first() {
reasons.push(S::OutputKind {
offered: o.output.clone(),
required: RequiredKind::TextRecord,
});
} else {
reasons.push(S::Operation(Operation::Generate));
}
}
}
if c.binding.worst_case_projection_bytes > b.input_limit.max_bytes {
reasons.push(S::InputLimit {
max: b.input_limit.max_bytes,
needed: c.binding.worst_case_projection_bytes,
});
}
if b.determinism < g.backend.min_determinism {
reasons.push(S::Determinism {
offered: format!("{:?}", b.determinism),
required: format!("{:?}", g.backend.min_determinism),
});
}
if let ArtifactPin::Pinned(a) = &g.backend.artifact
&& a != &b.artifact
{
reasons.push(S::ArtifactPin {
pinned: a.to_string(),
offered: b.artifact.to_string(),
});
}
if reasons.is_empty() {
Ok(chosen.unwrap().output.clone())
} else {
Err(reasons)
}
}
pub(crate) fn bind(
id: &str,
g: &Generate,
c: &Checked,
sorted: &[&BackendDescriptor],
) -> Result<GenerateBinding, Refusal> {
if !matches!(g.language, Language::Literal(_))
|| !matches!(g.limits.per_item_deadline_ms, ModelBound::Literal(_))
{
return Err(error(C::Template, id, "unresolved generation parameter"));
}
let mut shortfalls = vec![];
for b in sorted.iter().filter(|b| match &g.backend.binding {
BindingChoice::Auto => true,
BindingChoice::Backend(id) => id == &b.backend_id,
}) {
match candidate(g, c, b) {
Ok(_) => {
let mut binding = c.binding.clone();
binding.backend_id = b.backend_id.clone();
binding.artifact = b.artifact.clone();
binding.descriptor = b.id().map_err(|e| error(C::Parse, id, e))?;
if let ScreenOutput::Screener { backend } = &g.screen.output {
let max_bytes = g
.output
.fields
.iter()
.filter_map(|f| match f.ty {
GeneratedType::Text { max_bytes, .. } => Some(max_bytes),
_ => None,
})
.max()
.unwrap_or(0);
let bound = crate::compile::screening::projection_bound(max_bytes);
let screener = sorted.iter().filter(|b| {
matches!(&backend.binding, BindingChoice::Auto) || matches!(&backend.binding, BindingChoice::Backend(id) if id == &b.backend_id)
}).find(|b| {
b.determinism >= backend.min_determinism
&& (matches!(backend.artifact, ArtifactPin::Any) || matches!(&backend.artifact, ArtifactPin::Pinned(a) if a == &b.artifact))
&& b.input_limit.on_excess == rustev_contract::descriptor::InputExcess::Refuse
&& b.input_limit.max_bytes >= bound
&& b.operations.iter().any(|o| o.operation == Operation::Proposition && o.output == OutputKind::Screen && o.max_options >= 2 && o.screen.as_ref().is_some_and(|p| p.text_unit_bytes > 0 && p.max_text_bytes >= max_bytes))
}).ok_or_else(|| error(C::NoCapableBackend, id, "no backend satisfies output screening"))?;
binding.output_screener = Some(rustev_contract::screening::ScreenerBinding {
backend_id: screener.backend_id.clone(),
artifact: screener.artifact.clone(),
descriptor: screener.id().map_err(|e| error(C::Parse, id, e))?,
});
binding.worst_case_projection_bytes =
binding.worst_case_projection_bytes.max(bound);
}
return Ok(binding);
}
Err(reasons) => shortfalls.push(Shortfall {
backend_id: b.backend_id.clone(),
reasons,
}),
}
}
if shortfalls.is_empty()
&& let BindingChoice::Backend(b) = &g.backend.binding
{
shortfalls.push(Shortfall {
backend_id: b.clone(),
reasons: vec![S::UnknownBackend],
});
}
Err(Refusal {
category: C::NoCapableBackend,
subject: format!("step:{id}"),
detail: "no backend satisfies generate".into(),
shortfalls,
})
}
pub(crate) fn budget(
def: &Definition,
details: &BTreeMap<String, PlanStepDetail>,
) -> Result<u64, Refusal> {
let mut total = 0u64;
for (id, d) in details {
if let PlanStepDetail::Generate(g) = d {
total = total.saturating_add(g.worst_case_requests);
if g.worst_case_projection_bytes > def.limits.max_projection_bytes
&& def.limits.on_excess == ExcessPolicy::Refuse
{
return Err(error(
C::Budget,
id,
"generation projection exceeds max_projection_bytes",
));
}
}
}
Ok(total)
}
pub(crate) fn checked_binding(
id: &str,
g: &Generate,
binding: &GenerateBinding,
) -> Result<Checked, Refusal> {
let output_bytes = g.output.fields.iter().try_fold(0u64, |n, f| {
Ok(n.saturating_add(match &f.ty {
GeneratedType::Text { max_bytes, .. } => *max_bytes,
GeneratedType::List {
vocabulary,
max_items,
} => max_items.saturating_mul(
binding
.vocabularies
.get(vocabulary)
.ok_or_else(|| {
error(
C::InvalidGeneration,
id,
format!("unknown vocabulary {vocabulary}"),
)
})?
.iter()
.map(|s| s.len() as u64)
.max()
.unwrap_or(0),
),
}))
})?;
Ok(Checked {
binding: binding.clone(),
output_bytes,
prompt: None,
backstops: BTreeMap::new(),
})
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn checked_binding_refuses_missing_vocabulary() {
let plan: rustev_contract::plan::Plan =
serde_json::from_str(include_str!("testdata/generation.plan.json")).unwrap();
let StepBody::Generate(g) = &plan.definition.steps[0].body else {
panic!("expected generate declaration");
};
let PlanStepDetail::Generate(mut binding) = plan.steps[0].detail.clone() else {
panic!("expected generate binding");
};
assert_eq!(
checked_binding("item_text", g, &binding)
.unwrap()
.output_bytes,
548
);
binding.vocabularies.remove("tag_vocabulary");
let refusal = checked_binding("item_text", g, &binding).err().unwrap();
assert_eq!(refusal.category, C::InvalidGeneration);
assert_eq!(refusal.category as u8, 22);
assert_eq!(refusal.subject, "step:item_text");
assert_eq!(refusal.detail, "unknown vocabulary tag_vocabulary");
}
}