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Merged
zharinov merged 1 commit into from
Jan 6, 2026
Merged

refactor: Add invariant enforcement to engine #297

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113 changes: 71 additions & 42 deletions crates/plotnik-lib/src/engine/materializer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -46,10 +46,10 @@ impl<'a> ValueMaterializer<'a> {

/// Create initial builder based on result type.
fn builder_for_type(&self, type_id: TypeId) -> Builder {
let def = match self.types.get(type_id) {
Some(d) => d,
None => return Builder::Scalar(None),
};
let def = self
.types
.get(type_id)
.unwrap_or_else(|| panic!("unknown type_id {}", type_id.0));

match TypeKind::from_u8(def.kind) {
Some(TypeKind::Struct) => Builder::Object(vec![]),
Expand Down Expand Up @@ -84,6 +84,15 @@ impl Builder {
},
}
}

fn kind(&self) -> &'static str {
match self {
Builder::Scalar(_) => "Scalar",
Builder::Array(_) => "Array",
Builder::Object(_) => "Object",
Builder::Tagged { .. } => "Tagged",
}
}
}

impl<'t> Materializer<'t> for ValueMaterializer<'_> {
Expand All @@ -100,7 +109,7 @@ impl<'t> Materializer<'t> for ValueMaterializer<'_> {
// Pending value from Node/Text/Null (consumed by Set/Push)
let mut pending: Option<Value> = None;

for effect in effects {
for (effect_idx, effect) in effects.iter().enumerate() {
match effect {
RuntimeEffect::Node(n) => {
pending = Some(Value::Node(NodeHandle::from_node(*n, self.source)));
Expand All @@ -119,48 +128,63 @@ impl<'t> Materializer<'t> for ValueMaterializer<'_> {
stack.push(Builder::Array(vec![]));
}
RuntimeEffect::Push => {
// Take pending value (or completed container) and push to parent array
let val = pending.take().unwrap_or(Value::Null);
if let Some(Builder::Array(arr)) = stack.last_mut() {
arr.push(val);
}
let Some(Builder::Array(arr)) = stack.last_mut() else {
panic!(
"effect {effect_idx}: Push expects Array on stack, found {:?}",
stack.last().map(|b| b.kind())
);
};
arr.push(val);
}
RuntimeEffect::EndArr => {
if let Some(Builder::Array(arr)) = stack.pop() {
pending = Some(Value::Array(arr));
}
let top = stack.pop();
let Some(Builder::Array(arr)) = top else {
panic!(
"effect {effect_idx}: EndArr expects Array on stack, found {:?}",
top.as_ref().map(|b| b.kind())
);
};
pending = Some(Value::Array(arr));
}
RuntimeEffect::Obj => {
stack.push(Builder::Object(vec![]));
}
RuntimeEffect::Set(idx) => {
let field_name = self.resolve_member_name(*idx);
let val = pending.take().unwrap_or(Value::Null);
// Set works on both Object and Tagged (enum variant data)
match stack.last_mut() {
Some(Builder::Object(obj)) => obj.push((field_name, val)),
Some(Builder::Tagged { fields, .. }) => fields.push((field_name, val)),
_ => {}
other => panic!(
"effect {effect_idx}: Set expects Object/Tagged on stack, found {:?}",
other.map(|b| b.kind())
),
}
}
RuntimeEffect::EndObj => {
if let Some(Builder::Object(fields)) = stack.pop() {
if !fields.is_empty() {
// Non-empty object: always produce the object value
pending = Some(Value::Object(fields));
} else if pending.is_none() {
// Empty object with no pending value:
// - If nested (stack.len() > 1): produce empty object {}
// This handles captured empty sequences like `{ } @x`
// Note: stack always has at least the result_builder, so we check > 1
// - If at root (stack.len() <= 1): void result → null
if stack.len() > 1 {
pending = Some(Value::Object(vec![]));
}
// else: pending stays None (void result)
let top = stack.pop();
let Some(Builder::Object(fields)) = top else {
panic!(
"effect {effect_idx}: EndObj expects Object on stack, found {:?}",
top.as_ref().map(|b| b.kind())
);
};
if !fields.is_empty() {
// Non-empty object: always produce the object value
pending = Some(Value::Object(fields));
} else if pending.is_none() {
// Empty object with no pending value:
// - If nested (stack.len() > 1): produce empty object {}
// This handles captured empty sequences like `{ } @x`
// Note: stack always has at least the result_builder, so we check > 1
// - If at root (stack.len() <= 1): void result → null
if stack.len() > 1 {
pending = Some(Value::Object(vec![]));
}
// else: pending has a value, keep it (passthrough for enums, suppressive, etc.)
// else: pending stays None (void result)
}
// else: pending has a value, keep it (passthrough for enums, suppressive, etc.)
}
RuntimeEffect::Enum(idx) => {
let tag = self.resolve_member_name(*idx);
Expand All @@ -172,22 +196,27 @@ impl<'t> Materializer<'t> for ValueMaterializer<'_> {
});
}
RuntimeEffect::EndEnum => {
if let Some(Builder::Tagged {
let top = stack.pop();
let Some(Builder::Tagged {
tag,
payload_type,
fields,
}) = stack.pop()
{
// Void payloads produce no $data field
let data = if self.is_void_type(payload_type) {
None
} else {
// If inner returned a structured value (via Obj/EndObj), use it as data
// Otherwise use fields collected from direct Set effects
Some(Box::new(pending.take().unwrap_or(Value::Object(fields))))
};
pending = Some(Value::Tagged { tag, data });
}
}) = top
else {
panic!(
"effect {effect_idx}: EndEnum expects Tagged on stack, found {:?}",
top.as_ref().map(|b| b.kind())
);
};
// Void payloads produce no $data field
let data = if self.is_void_type(payload_type) {
None
} else {
// If inner returned a structured value (via Obj/EndObj), use it as data
// Otherwise use fields collected from direct Set effects
Some(Box::new(pending.take().unwrap_or(Value::Object(fields))))
};
pending = Some(Value::Tagged { tag, data });
}
RuntimeEffect::Clear => {
pending = None;
Expand Down
5 changes: 4 additions & 1 deletion crates/plotnik-lib/src/engine/value.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,10 @@ pub struct NodeHandle {
impl NodeHandle {
/// Create from a tree-sitter node and source text.
pub fn from_node(node: Node<'_>, source: &str) -> Self {
let text = node.utf8_text(source.as_bytes()).unwrap_or("").to_owned();
let text = node
.utf8_text(source.as_bytes())
.expect("node text extraction failed")
.to_owned();
Self {
kind: node.kind().to_owned(),
text,
Expand Down
15 changes: 10 additions & 5 deletions crates/plotnik-lib/src/engine/vm.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,13 +9,15 @@ use crate::bytecode::{
};

/// Get the nav for continue_search (always a sibling move).
/// Up/Stay variants return Next as a default since they don't do sibling search.
fn continuation_nav(nav: Nav) -> Nav {
match nav {
Nav::Down | Nav::Next => Nav::Next,
Nav::DownSkip | Nav::NextSkip => Nav::NextSkip,
Nav::DownExact | Nav::NextExact => Nav::NextExact,
// Up/Stay don't have search loops
_ => Nav::Next,
Nav::Up(_) | Nav::UpSkipTrivia(_) | Nav::UpExact(_) | Nav::Stay | Nav::StayExact => {
Nav::Next
}
}
}

Expand All @@ -24,13 +26,13 @@ use super::cursor::{CursorWrapper, SkipPolicy};

/// Derive skip policy from navigation mode without navigating.
/// Used when retrying a Call to determine the policy for the next checkpoint.
/// Stay/Up variants return None since they don't retry among siblings.
fn skip_policy_for_nav(nav: Nav) -> Option<SkipPolicy> {
match nav {
Nav::Down | Nav::Next => Some(SkipPolicy::Any),
Nav::DownSkip | Nav::NextSkip => Some(SkipPolicy::Trivia),
Nav::DownExact | Nav::NextExact => Some(SkipPolicy::Exact),
// Stay doesn't navigate, Up doesn't retry among siblings
_ => None,
Nav::Stay | Nav::StayExact | Nav::Up(_) | Nav::UpSkipTrivia(_) | Nav::UpExact(_) => None,
}
}
use super::effect::{EffectLog, RuntimeEffect};
Expand Down Expand Up @@ -462,7 +464,10 @@ impl<'t> VM<'t> {
return;
}
SuppressEnd => {
self.suppress_depth = self.suppress_depth.saturating_sub(1);
self.suppress_depth = self
.suppress_depth
.checked_sub(1)
.expect("SuppressEnd without matching SuppressBegin");
tracer.trace_suppress_control(SuppressEnd, self.suppress_depth > 0);
return;
}
Expand Down