Fix ExtractFootprint annotations causing cache invalidation

node-graph/libraries/core-types/src/arena.rs

@@ -11,6 +11,12 @@ pub struct Arena {
 	drops: Mutex<Vec<DropEntry>>,
 }
 
+impl std::fmt::Debug for Arena {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		f.debug_struct("Arena").field("generation", &self.generation).field("size", &self.buf.len()).finish()
+	}
+}
+
 struct DropEntry {
 	offset: usize,
 	drop_fn: unsafe fn(*mut u8),

node-graph/libraries/core-types/src/context.rs

@@ -288,11 +288,7 @@ impl From<&[ContextFeature]> for ContextDependencies {
 				_ => ContextFeatures::empty(),
 			};
 		}
-		Self {
+		Self { extract, inject, sources: Vec::new() }
-			extract,
-			inject,
-			sources: Vec::new(),
-		}
 	}
 }
 
@@ -792,7 +788,13 @@ pub struct VarArgLink<'a> {
 	pub outer: Option<&'a VarArgLink<'a>>,
 }
 
-#[derive(Clone, Copy)]
+impl<'a> std::fmt::Debug for VarArgLink<'a> {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		f.debug_struct("VarArgLink").field("args_len", &self.args.len()).field("outer", &self.outer).finish()
+	}
+}
+
+#[derive(Clone, Copy, Debug)]
 pub struct EvalScope<'a> {
 	real_time: Option<f64>,
 	animation_time: Option<f64>,
@@ -1084,7 +1086,7 @@ impl CtxFamily for ContextImplFamily {
 	type Ctx<'s> = ContextImpl<'s>;
 }
 
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Debug)]
 pub struct ContextImpl<'a> {
 	index: IndexLink<'a>,
 	position: Option<&'a PositionLink<'a>>,

node-graph/nodes/gcore/src/memo.rs

@@ -41,11 +41,7 @@ where
 }
 
 #[node_macro::node(category(""), path(graphene_core::memo), skip_impl, extent(frame_memo_extent))]
-fn frame_memo<'e, T: Clone + 'static>(
+fn frame_memo<'e, T: Clone + 'static>(ctx: impl Ctx + CacheHash + ExtractArena<'e>, #[data] cell: ArenaCell<FrameTable<T, 32>>, content: impl Node<Context<'_>, Output = T>) -> GPoll<&'e T> {
-	ctx: impl Ctx + CacheHash + ExtractArena<'e>,
-	#[data] cell: ArenaCell<FrameTable<T, 32>>,
-	content: impl Node<Context<'_>, Output = T>,
-) -> GPoll<&'e T> {
 	let arena = ctx.arena();
 	let table = match cell.load(arena) {
 		Some(table) => table,
@@ -130,10 +126,10 @@ fn serialize_monitor<T: Clone + 'static + Send + Sync>(io: &MonitorValue<T>) ->
 mod tests {
 	use super::*;
 	use core_types::SourceId;
+	use core_types::Type;
 	use core_types::concrete;
 	use core_types::context::{ContextImpl, EvalScope};
 	use core_types::registry::{EdgeHandle, ErasedGNode, ErasedLendGNode};
-	use core_types::Type;
 	use std::sync::atomic::{AtomicU32, Ordering};
 
 	struct CountingNode(AtomicU32);

node-graph/nodes/gcore/src/ops.rs

@@ -1,3 +1,4 @@
+use core_types::ExtractAll;
 use core_types::runtime::SourceFuture;
 use core_types::{Ctx, ExtractFootprint, ops::Convert, ops::ConvertAsync, transform::Footprint};
 use std::marker::PhantomData;
@@ -17,12 +18,12 @@ fn into<T: Send + Into<O>, O: Send>(_: impl Ctx, value: T, #[data] _out_ty: Phan
 }
 
 #[node_macro::node(category(""), skip_impl)]
-fn convert<T: Send + Convert<O, C>, O: Send, C: Send>(ctx: impl Ctx + ExtractFootprint, value: T, converter: C, #[data] _out_ty: PhantomData<O>) -> O {
+fn convert<T: Send + Convert<O, C>, O: Send, C: Send>(ctx: impl Ctx + ExtractAll, value: T, converter: C, #[data] _out_ty: PhantomData<O>) -> O {
 	value.convert(*ctx.try_footprint().unwrap_or(&Footprint::DEFAULT), converter)
 }
 
 #[node_macro::node(category(""), skip_impl)]
-fn convert_async<T: Send + ConvertAsync<O, C>, O: Send + 'static, C: Send>(ctx: impl Ctx + ExtractFootprint, value: T, converter: C, #[data] _out_ty: PhantomData<O>) -> SourceFuture<O> {
+fn convert_async<T: Send + ConvertAsync<O, C>, O: Send + 'static, C: Send>(ctx: impl Ctx + ExtractAll, value: T, converter: C, #[data] _out_ty: PhantomData<O>) -> SourceFuture<O> {
 	value.convert(*ctx.try_footprint().unwrap_or(&Footprint::DEFAULT), converter)
 }
 

node-graph/nodes/graphic/src/artboard.rs

@@ -1,7 +1,7 @@
 use core_types::gpoll::Interrupt;
 use core_types::list::{Item, List};
 use core_types::transform::TransformMut;
-use core_types::{ATTR_BACKGROUND, ATTR_CLIP, ATTR_DIMENSIONS, ATTR_LOCATION, Color, Context, Ctx, DeriveCtx, ExtractFootprint};
+use core_types::{ATTR_BACKGROUND, ATTR_CLIP, ATTR_DIMENSIONS, ATTR_LOCATION, Color, Context, Ctx, DeriveCtx, ModifyFootprint};
 use glam::{DAffine2, DVec2};
 use graphic_types::graphic::{Graphic, IntoGraphicList};
 use graphic_types::{Artboard, Vector};
@@ -11,7 +11,7 @@ use vector_types::GradientStops;
 /// Constructs a single-element `Artboard[]` with the given content and metadata stored as row attributes.
 #[node_macro::node(category(""))]
 pub fn create_artboard<T: IntoGraphicList>(
-	ctx: impl Ctx + ExtractFootprint + DeriveCtx,
+	ctx: impl Ctx + DeriveCtx + ModifyFootprint,
 	/// Graphics to include within the artboard.
 	#[implementations(
 		Context -> List<Graphic>,

node-graph/nodes/graphic/src/graphic.rs

@@ -1,8 +1,8 @@
 use core_types::bounds::{BoundingBox, RenderBoundingBox};
+use core_types::gpoll::Interrupt;
 use core_types::list::{AttributeDyn, AttributeValueDyn, Item, List, ListDyn};
 use core_types::registry::types::{Angle, SignedInteger};
 use core_types::uuid::NodeId;
-use core_types::gpoll::Interrupt;
 use core_types::{ATTR_EDITOR_LAYER_PATH, ATTR_EDITOR_MERGED_LAYERS, ATTR_TRANSFORM, AnyHash, BlendMode, CacheHash, Color, Context, Ctx, DeriveCtx};
 use glam::{DAffine2, DVec2};
 use graphic_types::graphic::{Graphic, IntoGraphicList};

node-graph/nodes/transform/src/transform_nodes.rs

@@ -1,9 +1,9 @@
 use core::f64;
 use core_types::color::Color;
+use core_types::gpoll::Interrupt;
 use core_types::list::{List, ListDyn};
 use core_types::transform::{ApplyTransform, ScaleType, Transform};
-use core_types::gpoll::Interrupt;
+use core_types::{ATTR_TRANSFORM, Context, Ctx, DeriveCtx, InjectFootprint, ModifyFootprint};
-use core_types::{ATTR_TRANSFORM, Context, Ctx, DeriveCtx, ExtractFootprint, InjectFootprint, ModifyFootprint};
 use glam::{DAffine2, DMat2, DVec2};
 use graphic_types::Graphic;
 use graphic_types::Vector;
@@ -13,7 +13,7 @@ use vector_types::GradientStops;
 /// Applies the specified transform to the input value, which may be a graphic type or another transform.
 #[node_macro::node(category("Math: Transform"))]
 fn transform<T: ApplyTransform + 'static>(
-	ctx: impl Ctx + ExtractFootprint + DeriveCtx + ModifyFootprint,
+	ctx: impl Ctx + DeriveCtx + ModifyFootprint,
 	#[implementations(
 		Context -> DAffine2,
 		Context -> DVec2,

node-graph/rfcs/fine-grained-context-caching.md

@@ -126,6 +126,12 @@ pub trait ModifyIndex: ExtractIndex + InjectIndex {}
 pub trait ModifyVarArgs: ExtractVarArgs + InjectVarArgs {}
 ```
 
+### Authoring rule: forward with Modify*, consume with Extract*
+
+Declare a feature via `Modify*` when the node only reads it to compute a new value it injects for its children (a "forward"), and via `Extract*` only when the node genuinely consumes the value for its own output (a "sink").
+
+The analysis skips `Modify*` bounds but treats every `Extract*` bound as an *unconditional* requirement. Because `Modify*` is a supertrait of `Extract*`, a `Modify*` bound already grants the read capability (e.g. `modify_footprint`, which is `where Self: ExtractFootprint`), so it is a mistake to list both. Writing `impl Ctx + ExtractFootprint + ModifyFootprint` on a forwarding node re-introduces the feature as a hard dependency at every such node, which propagates up the whole tree and pins upstream memos to a value the node never actually consumes (e.g. a viewport pan invalidating a render cache that renders in local space). Use `impl Ctx + ModifyFootprint` alone.
+
 ### Conditional Context Dependencies
 
 Modify* traits represent a special case in context analysis: