Merge fix/630

crates/engine/src/cmd/file.rs

@@ -529,6 +529,7 @@ fn load_with(
 /// innermost first so outer instances settle last.
 fn link_instances(doc: &mut Document) {
     crate::style_vars::after_load(doc);
+    super::styles::apply_paint_bindings_on_load(doc);
     let mut insts: Vec<(usize, NodeId)> =
         doc.nodes().filter(|n| matches!(n.kind, NodeKind::Instance { .. })).map(|n| (doc.ancestors(n.id).len(), n.id)).collect();
     insts.sort_by_key(|a| std::cmp::Reverse(a.0));
@@ -1272,6 +1273,19 @@ fn append_pages(doc: &mut Document, other: &Document) -> Result<Vec<NodeId>> {
             map.insert(id, doc.alloc_id());
         }
     }
+    // Library copies a .fig import keeps (cached definitions) have no library record to follow:
+    // the layers of its store come along into the store of `doc`. Recorded copies are left to
+    // `merge_store`, which shares them with copies `doc` already has.
+    let cached: Vec<NodeId> = other
+        .library_store()
+        .and_then(|s| other.node(s))
+        .map(|s| s.children.iter().copied().filter(|root| other.libraries.import_of(*root).is_none()).collect())
+        .unwrap_or_default();
+    for root in &cached {
+        for id in other.subtree(*root) {
+            map.insert(id, doc.alloc_id());
+        }
+    }
     let mut new_pages = Vec::new();
     for pg in &other.pages {
         let Some(pn) = other.node(*pg) else { continue };
@@ -1289,6 +1303,13 @@ fn append_pages(doc: &mut Document, other: &Document) -> Result<Vec<NodeId>> {
         }
         new_pages.push(np);
     }
+    if !cached.is_empty() {
+        let store = doc.ensure_library_store();
+        for root in &cached {
+            let nodes: Vec<Node> = other.subtree(*root).into_iter().filter_map(|i| other.node(i).cloned()).collect();
+            doc.paste_nodes(&nodes, &map, *root, store, None)?;
+        }
+    }
     for new in map.values() {
         let src = doc.node(*new).and_then(|n| n.source).and_then(|s| map.get(&s).copied());
         if let (Some(src), Some(n)) = (src, doc.node_mut(*new)) {
@@ -1354,6 +1375,70 @@ mod rest_import_tests {
         doc.nodes().find(|n| matches!(n.kind, NodeKind::Instance { .. })).unwrap()
     }
 
+    /// What a .fig import with a cached library component leaves: the main in the hidden store, a
+    /// visible instance of it and a layer linked to the main's layer.
+    fn cached_import() -> Document {
+        let mut doc = Document::new("Cached");
+        let page = doc.first_page().unwrap();
+        let store = doc.ensure_library_store();
+        let main = doc
+            .create(store, NodeKind::Component { description: String::new(), props: Default::default() }, "Cached main", 0.0, 0.0, 20.0, 20.0)
+            .unwrap();
+        let body = doc.create(main, NodeKind::Rectangle, "Body", 0.0, 0.0, 20.0, 20.0).unwrap();
+        let inst =
+            doc.create(page, NodeKind::Instance { component: main, props: Default::default() }, "Cached instance", 0.0, 0.0, 20.0, 20.0).unwrap();
+        let mut copy = doc.node(body).unwrap().clone();
+        copy.id = doc.alloc_id();
+        copy.parent = None;
+        copy.source = Some(body);
+        let copy_id = copy.id;
+        doc.insert(copy, inst, None).unwrap();
+        assert!(doc.is_remote(main) && doc.node(copy_id).unwrap().source == Some(body));
+        doc
+    }
+
+    /// Pasting layers that use a cached main into another document leaves the main behind, as it
+    /// does for other mains that are not published: no link points at a layer of the target.
+    #[test]
+    fn pasting_instances_of_cached_components_leaves_no_dangling_links() {
+        let src = cached_import();
+        let mut doc = Document::new("Target");
+        let page = doc.first_page().unwrap();
+        for i in 0..8 {
+            doc.create(page, NodeKind::Rectangle, &format!("Filler {i}"), 0.0, 0.0, 5.0, 5.0).unwrap();
+        }
+        let inst = src.nodes().find(|n| n.name == "Cached instance").unwrap().id;
+        let ids = src.subtree(inst);
+        let map: std::collections::BTreeMap<NodeId, NodeId> = ids.iter().map(|i| (*i, doc.alloc_id())).collect();
+        let nodes: Vec<Node> = ids.iter().filter_map(|i| src.node(*i).cloned()).collect();
+        doc.paste_nodes(&nodes, &map, inst, page, None).unwrap();
+        crate::library::adopt_pasted(&mut doc, &src, None, &map).unwrap();
+        let pasted = doc.node(map[&inst]).unwrap();
+        let NodeKind::Instance { component, .. } = pasted.kind else { panic!() };
+        assert!(!doc.contains(component), "the main stays behind: {component:?}");
+        assert!(doc.node(pasted.children[0]).unwrap().source.is_none_or(|s| !doc.contains(s)));
+    }
+
+    #[test]
+    fn appending_pages_with_cached_library_components_brings_the_components() {
+        let other = cached_import();
+        let mut doc = Document::new("Target");
+        let page = doc.first_page().unwrap();
+        // Ids of the target that would collide with the other document's store.
+        for i in 0..8 {
+            doc.create(page, NodeKind::Rectangle, &format!("Filler {i}"), 0.0, 0.0, 5.0, 5.0).unwrap();
+        }
+        append_pages(&mut doc, &other).unwrap();
+        assert!(doc.validate().is_empty(), "{:?}", doc.validate());
+        assert!(crate::components::mirror_issues(&doc).is_empty(), "{:?}", crate::components::mirror_issues(&doc));
+        let inst = doc.nodes().find(|n| n.name == "Cached instance").unwrap();
+        let NodeKind::Instance { component, .. } = inst.kind else { panic!() };
+        assert_eq!(doc.node(component).unwrap().name, "Cached main");
+        assert!(doc.is_remote(component), "the main comes along into the store");
+        let layer = doc.node(inst.children[0]).unwrap();
+        assert_eq!(layer.source, doc.node(component).unwrap().children.first().copied());
+    }
+
     #[test]
     fn rest_json_loads_with_linked_instances() {
         let bytes = serde_json::to_vec(&kit()).unwrap();

crates/engine/src/cmd/styles.rs

@@ -913,6 +913,24 @@ pub fn apply_bindings(doc: &mut Document) {
 
 /// [`apply_bindings`] for the layers `only` (every bound layer when `None`).
 pub fn apply_bindings_to(doc: &mut Document, only: Option<&std::collections::BTreeSet<NodeId>>) {
+    apply_bindings_matching(doc, only, |_| true);
+}
+
+/// Settle imported paint colours before the document is first shown. Other bindings can affect
+/// layout or component structure, which must be resolved through the normal edit pipeline.
+pub(crate) fn apply_paint_bindings_on_load(doc: &mut Document) {
+    let pending = doc.take_dirty();
+    apply_bindings_matching(doc, None, |field| {
+        super::lists::list_binding(field).is_some_and(|(list, _, prop)| {
+            matches!(list, super::lists::BoundList::Fills | super::lists::BoundList::Strokes)
+                && (prop == "color" || super::lists::stop_binding(prop).is_some())
+        })
+    });
+    doc.take_dirty();
+    doc.mark_dirty(pending);
+}
+
+fn apply_bindings_matching(doc: &mut Document, only: Option<&std::collections::BTreeSet<NodeId>>, include: impl Fn(&str) -> bool) {
     use super::lists::{BoundList, list_binding};
     if doc.variables.variables.is_empty() {
         return;
@@ -932,6 +950,9 @@ pub fn apply_bindings_to(doc: &mut Document, only: Option<&std::collections::BTr
         let mut grid_sets: Vec<(usize, String, f64)> = Vec::new();
         let mut prop_sets: Vec<(String, VariableValue)> = Vec::new();
         for (field, var) in binds {
+            if !include(&field) {
+                continue;
+            }
             let Some(val) = doc.variables.resolve(&var, &modes) else { continue };
             // One list item's value: a paint's colour, an effect's or a layout grid's field.
             if let Some((list, i, prop)) = list_binding(&field) {

crates/engine/src/components.rs

@@ -1710,6 +1710,165 @@ pub fn refused_override(before: &Document, after: &Document, id: NodeId) -> Opti
     None
 }
 
+/// Bounded source and parent lookups while a rebase reads an unchanged document.
+struct RebaseSources<'a> {
+    doc: &'a Document,
+    chains: BTreeMap<NodeId, Option<Vec<NodeId>>>,
+    parents: BTreeMap<(NodeId, NodeId), Option<bool>>,
+    main_changes: BTreeMap<NodeId, bool>,
+}
+
+impl<'a> RebaseSources<'a> {
+    const PARENTS: usize = 512;
+    const CACHE: usize = 8192;
+
+    fn new(doc: &'a Document) -> Self {
+        Self { doc, chains: BTreeMap::new(), parents: BTreeMap::new(), main_changes: BTreeMap::new() }
+    }
+
+    fn chain(&mut self, source: NodeId) -> Option<Vec<NodeId>> {
+        if let Some(chain) = self.chains.get(&source) {
+            return chain.clone();
+        }
+        let read = || {
+            let mut chain = Vec::new();
+            let mut seen = BTreeSet::new();
+            let mut current = Some(source);
+            for _ in 0..MAX_DEPTH {
+                let Some(id) = current else { return Some(chain) };
+                if !seen.insert(id) {
+                    return None;
+                }
+                let n = self.doc.node(id)?;
+                chain.push(id);
+                current = n.source;
+            }
+            current.is_none().then_some(chain)
+        };
+        let chain = read();
+        if self.chains.len() < Self::CACHE {
+            self.chains.insert(source, chain.clone());
+        }
+        chain
+    }
+
+    /// Validate the complete parent chain, even if `main` was found before a cycle.
+    fn in_main(&mut self, id: NodeId, main: NodeId) -> Option<bool> {
+        if let Some(found) = self.parents.get(&(id, main)) {
+            return *found;
+        }
+        let read = || {
+            let mut current = Some(id);
+            let mut seen = BTreeSet::new();
+            let mut found = false;
+            for _ in 0..Self::PARENTS {
+                let Some(id) = current else { return Some(found) };
+                if !seen.insert(id) {
+                    return None;
+                }
+                found |= id == main;
+                current = self.doc.node(id)?.parent;
+            }
+            current.is_none().then_some(found)
+        };
+        let found = read();
+        if self.parents.len() < Self::CACHE {
+            self.parents.insert((id, main), found);
+        }
+        found
+    }
+
+    fn member(&mut self, source: NodeId, main: NodeId, target: NodeId) -> Option<NodeId> {
+        let chain = self.chain(source)?;
+        if chain.contains(&target) {
+            return None;
+        }
+        let mut member = None;
+        for id in chain {
+            if self.in_main(id, main)? && id != main && member.is_none() {
+                member = Some(id);
+            }
+        }
+        member
+    }
+
+    /// Nearest enclosing instances and their current mains. Slots with own content end scope.
+    fn owners(&self, id: NodeId) -> Option<Vec<(NodeId, NodeId)>> {
+        let mut owners = Vec::new();
+        let mut current = self.doc.node(id)?.parent;
+        let mut seen = BTreeSet::from([id]);
+        for _ in 0..Self::PARENTS {
+            let Some(id) = current else { return Some(owners) };
+            if !seen.insert(id) {
+                return None;
+            }
+            let n = self.doc.node(id)?;
+            if holds_content(n) {
+                return Some(owners);
+            }
+            if let NodeKind::Instance { component, .. } = &n.kind {
+                owners.push((id, *component));
+            }
+            current = n.parent;
+        }
+        current.is_none().then_some(owners)
+    }
+
+    fn contextual(&mut self, source: NodeId, owners: &[(NodeId, NodeId)]) -> bool {
+        owners.iter().any(|(_, main)| self.in_main(source, *main) == Some(true) && source != *main)
+    }
+
+    /// A contextual child belongs to the same placed slot as its enclosing instance.
+    fn valid(&mut self, source: NodeId, target: NodeId, owners: &[(NodeId, NodeId)]) -> bool {
+        let Some((owner, main)) = owners.first() else { return false };
+        if self.member(source, *main, target).is_none() {
+            return false;
+        }
+        if self.in_main(source, *main) == Some(true) {
+            return true;
+        }
+        let Some(source_owner) = self.doc.node(*owner).and_then(|n| n.source) else { return false };
+        matches!(self.doc.node(source_owner).map(|n| &n.kind), Some(NodeKind::Instance { component, .. }) if component == main)
+            && self.owners(source).and_then(|owners| owners.first().copied()).is_some_and(|(id, _)| id == source_owner)
+    }
+
+    fn placed(&mut self, id: NodeId, owners: &[(NodeId, NodeId)]) -> Option<NodeId> {
+        let source = self.doc.node(id)?.source?;
+        if !matches!(self.doc.node(source)?.kind, NodeKind::Instance { .. } | NodeKind::Frame)
+            || !self.valid(source, id, owners)
+            || !self.contextual(source, owners)
+        {
+            return None;
+        }
+        Some(source)
+    }
+
+    fn beneath_swap(&mut self, owners: &[(NodeId, NodeId)], stop: NodeId) -> bool {
+        for (index, (id, main)) in owners.iter().enumerate() {
+            if *id == stop {
+                break;
+            }
+            let changed = if let Some(changed) = self.main_changes.get(id) {
+                *changed
+            } else {
+                let changed = self.placed(*id, &owners[index + 1..]).is_some_and(|source| match self.doc.node(source).map(|n| &n.kind) {
+                    Some(NodeKind::Instance { component, .. }) => component != main,
+                    Some(NodeKind::Frame) => true,
+                    _ => false,
+                });
+                if self.main_changes.len() < Self::CACHE {
+                    self.main_changes.insert(*id, changed);
+                }
+                changed
+            };
+            if changed {
+                return true;
+            }
+        }
+        false
+    }
+}
+
 /// Re-derive `source` links and overrides of instance `inst` against its own main by comparing
 /// values (after detaching an outer instance, restoring a main, or copying a nested instance out):
 /// the look is kept exactly. Values a component property sets aren't overrides.
@@ -1722,22 +1881,28 @@ pub fn rebase_instance(doc: &mut Document, inst: NodeId) {
         diff_groups(a, b).into_iter().filter(|g| !matches!(*g, "size" | "position")).map(str::to_string).collect()
     };
     let mut updates = Vec::new();
+    let mut sources = RebaseSources::new(doc);
+    let root_owners = sources.owners(inst).unwrap_or_default();
+    let placed_source = sources.placed(inst, &root_owners);
+    let mut contexts = vec![(inst, component)];
+    contexts.extend_from_slice(&root_owners);
     for (id, path) in &mine {
         let Some(n) = doc.node(*id) else { continue };
-        // Follow the source chain into the main first (exact), then fall back to the name path.
-        let mut main = None;
-        let mut cur = n.source;
-        for _ in 0..MAX_DEPTH {
-            let Some(c) = cur else { break };
-            if c != component && doc.contains(c) && doc.is_ancestor(component, c) {
-                main = Some(c);
-                break;
-            }
-            cur = doc.node(c).and_then(|x| x.source);
+        let owners = sources.owners(*id).unwrap_or_default();
+        let nearest_main = owners.first().map(|(_, main)| *main);
+        let valid_source = n.source.filter(|source| sources.valid(*source, *id, &owners));
+        let mut main = valid_source.and_then(|source| sources.member(source, component, *id));
+        // A swapped or Frame-to-Instance subtree is compared to its current main by the inner
+        // rebase. An outer name path must not rebind those children to the old expanded copies.
+        if main.is_none() && valid_source.is_some() && sources.beneath_swap(&owners, inst) {
+            updates.push((*id, valid_source, n.overrides.clone()));
+            continue;
         }
-        let main = main.or_else(|| theirs.get(path).copied());
+        main = main
+            .or_else(|| theirs.get(path).copied().filter(|source| nearest_main.is_some_and(|scope| sources.member(*source, scope, *id).is_some())));
+        let source = valid_source.filter(|source| sources.contextual(*source, &contexts)).filter(|_| main.is_some()).or(main);
         let mut overrides: BTreeSet<String> = n.overrides.iter().filter(|g| !matches!(g.as_str(), "component" | "props")).cloned().collect();
-        if let Some(m) = main.and_then(|m| doc.node(m)) {
+        if let Some(m) = source.and_then(|source| doc.node(source)) {
             let mut bound: Vec<&str> = m.prop_refs.keys().map(|f| field_group(f)).collect();
             bound.extend(variable_groups(n, m));
             overrides.extend(value_groups(m, n).into_iter().filter(|g| !bound.contains(&g.as_str())));
@@ -1745,36 +1910,51 @@ pub fn rebase_instance(doc: &mut Document, inst: NodeId) {
                 overrides.insert("component".into());
             }
         }
-        updates.push((*id, main, overrides));
+        updates.push((*id, source, overrides));
     }
-    for (id, main, overrides) in updates {
-        if let Some(n) = doc.node_mut(id) {
-            n.source = main;
-            n.overrides = if main.is_some() { overrides } else { BTreeSet::new() };
-        }
-    }
-    let root_groups = match (doc.node(component), doc.node(inst)) {
+    // A placed nested root compares to its actual slot. A detached root compares to its own main.
+    let root_base = placed_source.or_else(|| {
+        let chain = sources.chain(component)?;
+        (!chain.contains(&inst) && sources.in_main(component, inst) == Some(false)).then_some(component)
+    });
+    let root_groups = match (root_base.and_then(|source| doc.node(source)), doc.node(inst)) {
         (Some(m), Some(n)) => {
             let from_variables = variable_groups(n, m);
             let mut groups: Vec<String> = value_groups(m, n)
                 .into_iter()
                 .filter(|g| !matches!(g.as_str(), "name" | "exports" | "interactions") && !from_variables.contains(&g.as_str()))
                 .collect();
-            // A layer name of its own (a nested instance renamed in its old main) stays.
-            if n.name != default_instance_name(doc, component) {
+            let named = if placed_source.is_some() { n.name != m.name } else { n.name != default_instance_name(doc, component) };
+            if named {
                 groups.push("name".into());
             }
+            if placed_source.is_some()
+                && matches!((&m.kind, &n.kind), (NodeKind::Instance { component: a, .. }, NodeKind::Instance { component: b, .. }) if a != b)
+            {
+                groups.push("component".into());
+            }
             groups
         }
         _ => Vec::new(),
     };
+    drop(sources);
+    for (id, main, overrides) in updates {
+        if let Some(n) = doc.node_mut(id) {
+            n.source = main;
+            n.overrides = if main.is_some() { overrides } else { BTreeSet::new() };
+        }
+    }
     if let Some(n) = doc.node_mut(inst) {
-        n.source = Some(component);
+        n.source = root_base;
         n.overrides.retain(|g| !matches!(g.as_str(), "component" | "props" | "position"));
         n.overrides.extend(root_groups);
     }
 }
 
+#[cfg(test)]
+#[path = "components_rebase_source_tests.rs"]
+mod rebase_source_tests;
+
 /// A set's default variant: the one in its top-left corner (nearest to it, then the top-most, then
 /// the left-most).
 pub fn default_variant(doc: &Document, set: NodeId) -> Option<NodeId> {

crates/engine/src/components_rebase_source_tests.rs

@@ -0,0 +1,244 @@
+//! Contextual import sources survive rebasing; detached and swapped subtrees use their current mains.
+
+use super::*;
+
+fn add(doc: &mut Document, parent: NodeId, kind: NodeKind, name: &str) -> NodeId {
+    doc.create(parent, kind, name, 0.0, 0.0, 20.0, 20.0).unwrap()
+}
+
+fn component(doc: &mut Document, parent: NodeId, name: &str) -> NodeId {
+    add(doc, parent, NodeKind::Component { description: String::new(), props: BTreeMap::new() }, name)
+}
+
+fn mirror(doc: &mut Document, source: NodeId, parent: NodeId) -> NodeId {
+    let mut n = doc.node(source).unwrap().clone();
+    let children = std::mem::take(&mut n.children);
+    n.id = doc.alloc_id();
+    n.parent = None;
+    n.source = Some(source);
+    let id = n.id;
+    doc.insert(n, parent, None).unwrap();
+    for child in children {
+        mirror(doc, child, id);
+    }
+    id
+}
+
+fn instance(doc: &mut Document, main: NodeId, parent: NodeId, name: &str) -> NodeId {
+    let mut n = doc.node(main).unwrap().clone();
+    let children = std::mem::take(&mut n.children);
+    n.id = doc.alloc_id();
+    n.kind = NodeKind::Instance { component: main, props: BTreeMap::new() };
+    n.name = name.into();
+    n.parent = None;
+    n.source = None;
+    let id = n.id;
+    doc.insert(n, parent, None).unwrap();
+    for child in children {
+        mirror(doc, child, id);
+    }
+    id
+}
+
+struct Scene {
+    doc: Document,
+    inner: NodeId,
+    base: NodeId,
+    slot: NodeId,
+    context: NodeId,
+    root: NodeId,
+    nested: NodeId,
+    child: NodeId,
+}
+
+fn scene() -> Scene {
+    let mut doc = Document::new("Source context");
+    let page = doc.first_page().unwrap();
+    let inner = component(&mut doc, page, "Inner");
+    let base = add(&mut doc, inner, NodeKind::Rectangle, "Body");
+    doc.node_mut(base).unwrap().transform = Affine::translate((2.0, 0.0));
+    let outer = component(&mut doc, page, "Outer");
+    let slot = instance(&mut doc, inner, outer, "Nested");
+    doc.node_mut(slot).unwrap().source = Some(inner);
+    let context = doc.node(slot).unwrap().children[0];
+    doc.node_mut(context).unwrap().transform = Affine::translate((3.0, 0.0));
+    doc.node_mut(context).unwrap().opacity = 0.3;
+    let root = instance(&mut doc, outer, page, "Outer copy");
+    let nested = doc.node(root).unwrap().children[0];
+    let child = doc.node(nested).unwrap().children[0];
+    doc.node_mut(child).unwrap().transform = Affine::translate((2.0, 0.0));
+    doc.node_mut(child).unwrap().opacity = 0.2;
+    Scene { doc, inner, base, slot, context, root, nested, child }
+}
+
+fn both(s: &mut Scene) {
+    rebase_instance(&mut s.doc, s.nested);
+    rebase_instance(&mut s.doc, s.root);
+}
+
+#[test]
+fn rebase_default_only_sources_promote_to_the_actual_outer_context() {
+    let mut s = scene();
+    s.doc.node_mut(s.nested).unwrap().source = None;
+    s.doc.node_mut(s.child).unwrap().source = None;
+    both(&mut s);
+    assert_eq!(s.doc.node(s.nested).unwrap().source, Some(s.slot));
+    assert_eq!(s.doc.node(s.child).unwrap().source, Some(s.context));
+}
+
+#[test]
+fn rebase_rejects_a_context_source_from_another_nested_slot() {
+    let mut s = scene();
+    let outer = s.doc.node(s.slot).unwrap().parent.unwrap();
+    let sibling = instance(&mut s.doc, s.inner, outer, "Other nested slot");
+    s.doc.node_mut(sibling).unwrap().source = Some(s.inner);
+    let sibling_child = s.doc.node(sibling).unwrap().children[0];
+    mirror(&mut s.doc, sibling, s.root);
+    s.doc.node_mut(s.child).unwrap().source = Some(sibling_child);
+    both(&mut s);
+    assert_eq!(s.doc.node(s.nested).unwrap().source, Some(s.slot));
+    assert_eq!(s.doc.node(s.child).unwrap().source, Some(s.context));
+    assert_eq!(s.doc.node(sibling_child).unwrap().transform.translation().x, 2.0);
+    assert_eq!(s.doc.node(s.context).unwrap().transform.translation().x, 3.0);
+}
+
+#[test]
+fn rebase_does_not_mark_inherited_context_values_as_local_overrides() {
+    let mut s = scene();
+    s.doc.node_mut(s.child).unwrap().opacity = 0.3;
+    both(&mut s);
+    assert_eq!(s.doc.node(s.child).unwrap().source, Some(s.context));
+    assert!(!s.doc.node(s.child).unwrap().overrides.contains("opacity"));
+}
+
+#[test]
+fn rebase_preserves_multilevel_context_without_shortening_source_chains() {
+    let mut doc = Document::new("Nested source contexts");
+    let page = doc.first_page().unwrap();
+    let inner = component(&mut doc, page, "Inner");
+    let base = add(&mut doc, inner, NodeKind::Rectangle, "Body");
+    doc.node_mut(base).unwrap().transform = Affine::translate((2.0, 0.0));
+    let wrapper = component(&mut doc, page, "Wrapper");
+    let default_slot = instance(&mut doc, inner, wrapper, "Nested");
+    doc.node_mut(default_slot).unwrap().source = Some(inner);
+    let outer = component(&mut doc, page, "Outer");
+    let wrapper_slot = instance(&mut doc, wrapper, outer, "Wrapper slot");
+    doc.node_mut(wrapper_slot).unwrap().source = Some(wrapper);
+    let source_slot = doc.node(wrapper_slot).unwrap().children[0];
+    let context = doc.node(source_slot).unwrap().children[0];
+    doc.node_mut(context).unwrap().transform = Affine::translate((3.0, 0.0));
+    let root = instance(&mut doc, outer, page, "Outer copy");
+    let wrapper_copy = doc.node(root).unwrap().children[0];
+    let nested = doc.node(wrapper_copy).unwrap().children[0];
+    let child = doc.node(nested).unwrap().children[0];
+    doc.node_mut(nested).unwrap().name = "Renamed nested".into();
+    doc.node_mut(child).unwrap().transform = Affine::translate((2.0, 0.0));
+    for id in [nested, wrapper_copy, root] {
+        rebase_instance(&mut doc, id);
+        assert_eq!(doc.node(nested).unwrap().source, Some(source_slot));
+        assert_eq!(doc.node(child).unwrap().source, Some(context));
+    }
+    assert_eq!(doc.node(context).unwrap().source, Some(doc.node(default_slot).unwrap().children[0]));
+    assert_eq!(doc.node(context).unwrap().transform.translation().x, 3.0);
+    assert_eq!(doc.node(child).unwrap().transform.translation().x, 2.0);
+}
+
+#[test]
+fn rebase_preserves_placed_frame_to_instance_and_current_main_children() {
+    let mut doc = Document::new("Typed nested source");
+    let page = doc.first_page().unwrap();
+    let inner = component(&mut doc, page, "Inner");
+    let body = add(&mut doc, inner, NodeKind::Rectangle, "Body");
+    let outer = component(&mut doc, page, "Outer");
+    let slot = add(&mut doc, outer, NodeKind::Frame, "Empty slot");
+    let root = instance(&mut doc, outer, page, "Outer copy");
+    let nested = doc.node(root).unwrap().children[0];
+    doc.node_mut(nested).unwrap().kind = NodeKind::Instance { component: inner, props: BTreeMap::new() };
+    let child = mirror(&mut doc, body, nested);
+    rebase_instance(&mut doc, nested);
+    rebase_instance(&mut doc, root);
+    assert_eq!(doc.node(nested).unwrap().source, Some(slot));
+    assert_eq!(doc.node(child).unwrap().source, Some(body));
+    assert!(matches!(doc.node(nested).unwrap().kind, NodeKind::Instance { component, .. } if component == inner));
+}
+
+#[test]
+fn rebase_keeps_current_main_sources_and_component_delta_beneath_swap() {
+    let mut s = scene();
+    let page = s.doc.first_page().unwrap();
+    let replacement = component(&mut s.doc, page, "Replacement");
+    let body = add(&mut s.doc, replacement, NodeKind::Rectangle, "Body");
+    s.doc.node_mut(body).unwrap().transform = Affine::translate((7.0, 0.0));
+    s.doc.node_mut(s.nested).unwrap().kind = NodeKind::Instance { component: replacement, props: BTreeMap::new() };
+    s.doc.remove(s.child).unwrap();
+    s.child = mirror(&mut s.doc, body, s.nested);
+    s.doc.node_mut(s.child).unwrap().transform = Affine::translate((8.0, 0.0));
+    s.doc.node_mut(s.nested).unwrap().name = "Renamed swap".into();
+    rebase_instance(&mut s.doc, s.nested);
+    assert_eq!(s.doc.node(s.nested).unwrap().source, Some(s.slot));
+    assert!(s.doc.node(s.nested).unwrap().overrides.contains("component"));
+    rebase_instance(&mut s.doc, s.root);
+    assert_eq!(s.doc.node(s.nested).unwrap().source, Some(s.slot));
+    assert_eq!(s.doc.node(s.child).unwrap().source, Some(body));
+    assert!(s.doc.node(s.nested).unwrap().overrides.contains("component"));
+    assert_eq!(s.doc.node(s.child).unwrap().transform.translation().x, 8.0);
+}
+
+#[test]
+fn rebase_detached_nested_uses_own_main_and_keeps_inherited_geometry() {
+    let mut s = scene();
+    let page = s.doc.first_page().unwrap();
+    let detached = mirror(&mut s.doc, s.nested, page);
+    let child = s.doc.node(detached).unwrap().children[0];
+    // The old source references still exist, but their Outer context is absent here.
+    s.doc.node_mut(detached).unwrap().source = Some(s.slot);
+    s.doc.node_mut(child).unwrap().source = Some(s.context);
+    s.doc.node_mut(child).unwrap().transform = Affine::translate((3.0, 0.0));
+    rebase_instance(&mut s.doc, detached);
+    assert_eq!(s.doc.node(detached).unwrap().source, Some(s.inner));
+    assert_eq!(s.doc.node(child).unwrap().source, Some(s.base));
+    assert_eq!(s.doc.node(child).unwrap().transform.translation().x, 3.0);
+    assert_eq!(s.doc.node(s.base).unwrap().transform.translation().x, 2.0);
+}
+
+#[test]
+fn rebase_does_not_preserve_existing_foreign_or_stale_sources() {
+    let mut s = scene();
+    let page = s.doc.first_page().unwrap();
+    let foreign = component(&mut s.doc, page, "Foreign");
+    let foreign_body = add(&mut s.doc, foreign, NodeKind::Rectangle, "Body");
+    s.doc.node_mut(s.child).unwrap().source = Some(foreign_body);
+    both(&mut s);
+    assert_ne!(s.doc.node(s.child).unwrap().source, Some(foreign_body));
+    assert_eq!(s.doc.node(s.child).unwrap().source, Some(s.context));
+    let mut s = scene();
+    let page = s.doc.first_page().unwrap();
+    let replacement = component(&mut s.doc, page, "Replacement");
+    let body = add(&mut s.doc, replacement, NodeKind::Rectangle, "Body");
+    s.doc.node_mut(s.nested).unwrap().kind = NodeKind::Instance { component: replacement, props: BTreeMap::new() };
+    s.doc.node_mut(s.child).unwrap().source = Some(s.context);
+    both(&mut s);
+    assert_ne!(s.doc.node(s.child).unwrap().source, Some(s.context), "the old default-main child is stale after a swap");
+    assert!(s.doc.node(s.child).unwrap().source.is_none() || s.doc.node(s.child).unwrap().source == Some(body));
+}
+
+#[test]
+fn rebase_rejects_source_and_parent_cycles_with_bounded_lookups() {
+    let mut s = scene();
+    s.doc.node_mut(s.base).unwrap().source = Some(s.context);
+    both(&mut s);
+    assert_eq!(s.doc.node(s.child).unwrap().source, None);
+    let mut s = scene();
+    s.doc.node_mut(s.context).unwrap().parent = Some(s.context);
+    both(&mut s);
+    assert_ne!(s.doc.node(s.child).unwrap().source, Some(s.context));
+    let mut s = scene();
+    s.doc.node_mut(s.nested).unwrap().parent = Some(s.child);
+    s.doc.node_mut(s.child).unwrap().parent = Some(s.nested);
+    let sources = RebaseSources::new(&s.doc);
+    assert!(sources.owners(s.child).is_none());
+    let mut s = scene();
+    s.doc.node_mut(s.root).unwrap().kind = NodeKind::Instance { component: s.root, props: BTreeMap::new() };
+    rebase_instance(&mut s.doc, s.root);
+    assert_ne!(s.doc.node(s.root).unwrap().source, Some(s.root));
+}

crates/engine/src/fig_import_tests.rs

@@ -50,3 +50,43 @@ fn local_samples_match_their_exports() {
         }
     }
 }
+
+/// Layers of an instance copy keep their link to the layer they stand for when the file is
+/// opened, also after they were renamed in the copy (a name is no identity), and the override
+/// that a rename is stays an override.
+#[test]
+fn opened_fig_links_instance_layers_by_identity_not_by_name() {
+    use base64::Engine as _;
+    let mut s = Session::new();
+    let make = |s: &mut Session, cmd: &str, p: serde_json::Value| s.execute(cmd, &p).unwrap()["id"].as_u64().map(figcraft_doc::NodeId).unwrap();
+    let body = make(&mut s, "frame.create", json!({"x": 0, "y": 0, "width": 40, "height": 20, "name": "Inner"}));
+    let label = make(&mut s, "text.create", json!({"text": "Label", "x": 2, "y": 2, "parent": body, "props": {"name": "Label"}}));
+    let inner = make(&mut s, "component.create", json!({"ids": [body]}));
+    let frame = make(&mut s, "frame.create", json!({"x": 100, "y": 0, "width": 200, "height": 60, "name": "Outer"}));
+    let outer = make(&mut s, "component.create", json!({"ids": [frame]}));
+    let slot = make(&mut s, "instance.create", json!({"component": inner, "x": 0, "y": 0, "parent": outer}));
+    s.execute("node.set", &json!({"id": slot, "props": {"name": "Slot"}})).unwrap();
+    let copy = make(&mut s, "instance.create", json!({"component": outer, "x": 0, "y": 200}));
+    let copy_slot = s.doc().unwrap().node(copy).unwrap().children[0];
+    let copy_label = s.doc().unwrap().node(copy_slot).unwrap().children[0];
+    s.execute("node.set", &json!({"id": copy_slot, "props": {"name": "Renamed slot"}})).unwrap();
+    s.execute("node.set", &json!({"id": copy_label, "props": {"name": "Renamed label"}})).unwrap();
+    let _ = label;
+
+    let exported = s.execute("file.export", &json!({"format": "fig"})).unwrap();
+    let path = std::env::temp_dir().join(format!("figcraft-slots-{}.fig", std::process::id()));
+    std::fs::write(&path, base64::engine::general_purpose::STANDARD.decode(exported["data"].as_str().unwrap()).unwrap()).unwrap();
+    let mut opened = Session::new();
+    let result = opened.execute("file.open", &json!({"path": path.to_string_lossy()}));
+    let _ = std::fs::remove_file(&path);
+    result.unwrap();
+    let doc = opened.doc().unwrap();
+    let outer = doc.nodes().find(|n| n.name == "Outer" && matches!(n.kind, NodeKind::Component { .. })).unwrap();
+    let copy = doc.nodes().find(|n| n.name == "Outer" && matches!(n.kind, NodeKind::Instance { .. })).unwrap();
+    let slot = doc.node(copy.children[0]).unwrap();
+    let label = doc.node(slot.children[0]).unwrap();
+    assert_eq!((slot.name.as_str(), label.name.as_str()), ("Renamed slot", "Renamed label"));
+    assert_eq!(slot.source, Some(outer.children[0]));
+    assert_eq!(label.source, Some(doc.node(outer.children[0]).unwrap().children[0]));
+    assert!(slot.overrides.contains("name") && label.overrides.contains("name"));
+}

crates/engine/src/lib.rs

@@ -401,6 +401,8 @@ impl DocState {
             doc.repair();
         }
         doc.link_layer_text_styles();
+        cmd::styles::apply_paint_bindings_on_load(&mut doc);
+        // Initial import settlement belongs to the saved baseline, not the user's first edit.
         let page = doc.current_page.filter(|p| doc.pages.contains(p)).or_else(|| doc.first_page()).unwrap_or(NodeId(0));
         let doc = Arc::new(doc);
         let mut st = Self {

crates/engine/src/library.rs

@@ -1221,9 +1221,16 @@ pub fn check_read_only(cmd: &str, before: &Document, after: &Document) -> std::r
     if !variables_unchanged(before, after) {
         return Err(READ_ONLY.into());
     }
-    let Some(store) = after.library_store().or_else(|| before.library_store()) else { return Ok(()) };
-    let touched = |d: &Document, id: NodeId| d.contains(id) && d.page_of(id) == Some(store);
-    if after.dirty().iter().any(|id| touched(before, *id) || touched(after, *id)) {
+    let changed_remote = |id| {
+        if !before.is_remote(id) && !after.is_remote(id) {
+            return false;
+        }
+        match (before.node_arc(id), after.node_arc(id)) {
+            (Some(old), Some(new)) => !Arc::ptr_eq(old, new),
+            _ => true,
+        }
+    };
+    if after.dirty().iter().any(|id| changed_remote(*id)) {
         return Err(READ_ONLY.into());
     }
     Ok(())

crates/engine/src/library_tests.rs

@@ -45,6 +45,38 @@ fn path_str(p: &std::path::Path) -> String {
     p.to_string_lossy().into_owned()
 }
 
+fn dirty_library_document() -> (Document, NodeId) {
+    let mut doc = Document::new("Dirty library cache");
+    let store = doc.ensure_library_store();
+    let remote = doc.alloc_id();
+    doc.insert(Node::new(remote, NodeKind::Frame, "Remote", 10.0, 10.0), store, None).unwrap();
+    (doc, remote)
+}
+
+/// An imported cache is dirty until the first edit; that alone is no edit of the library copies.
+#[test]
+fn read_only_allows_unchanged_predirty_remote_nodes() {
+    let (before, remote) = dirty_library_document();
+    assert!(before.dirty().contains(&remote));
+
+    let mut after = before.clone();
+    after.add_page("Unrelated page");
+    assert!(after.dirty().contains(&remote), "the imported remote node remains in the pending dirty set");
+    check_read_only("page.add", &before, &after).unwrap();
+
+    let mut edited = before.clone();
+    edited.get_mut(remote).unwrap().opacity = 0.5;
+    assert_eq!(check_read_only("node.set", &before, &edited), Err(READ_ONLY.into()));
+
+    let mut moved = before.clone();
+    moved.reparent(remote, before.first_page().unwrap(), None).unwrap();
+    assert_eq!(check_read_only("node.reparent", &before, &moved), Err(READ_ONLY.into()));
+
+    let mut deleted = before.clone();
+    deleted.remove(remote).unwrap();
+    assert_eq!(check_read_only("edit.delete", &before, &deleted), Err(READ_ONLY.into()));
+}
+
 /// The library file's layers.
 struct Kit {
     button: NodeId,
@@ -179,8 +211,16 @@ fn add_place_and_update_keep_overrides() {
         NodeKind::Instance { component, .. } => component,
         _ => panic!("not an instance"),
     };
+    let unchanged = s.doc().unwrap().clone();
     let e = s.execute("node.set", &json!({"id": remote_button, "props": {"fill": "#ff0000"}})).unwrap_err();
     assert!(e.to_string().contains("can't be edited"), "{e}");
+    assert_eq!(s.doc().unwrap(), &unchanged, "a refused remote edit rolls back");
+    for (cmd, args) in
+        [("node.reparent", json!({"ids": [remote_button], "parent": s.page().unwrap()})), ("edit.delete", json!({"ids": [remote_button]}))]
+    {
+        assert!(s.execute(cmd, &args).is_err(), "{cmd} must preserve read-only copies");
+        assert_eq!(s.doc().unwrap(), &unchanged, "refused {cmd} rolls back");
+    }
     let style = s.doc().unwrap().styles[0].id.clone();
     assert!(s.execute("style.update", &json!({"style": style, "name": "Mine"})).is_err());
     assert!(s.execute("style.delete", &json!({"style": style})).is_err());
@@ -281,10 +321,16 @@ fn library_styles_apply_and_import_with_pages() {
     let copy = doc.nodes().find(|n| n.name == node(&s, inst).name && matches!(n.kind, NodeKind::Instance { .. }) && !doc.is_remote(n.id)).unwrap();
     let NodeKind::Instance { component, .. } = copy.kind else { panic!("not an instance") };
     assert!(doc.is_remote(component));
+    let store_roots = |s: &Session| {
+        let doc = s.doc().unwrap();
+        doc.library_store().and_then(|id| doc.node(id)).map_or(0, |n| n.children.len())
+    };
+    assert_eq!(store_roots(&t), 2, "recorded copies are not copied twice");
     // A second import shares the copies it already has.
     ex(&mut t, "file.import", json!({"path": path}));
     healthy(&t);
     assert_eq!(t.doc().unwrap().libraries.components.len(), 2);
+    assert_eq!(store_roots(&t), 2);
     let _ = std::fs::remove_dir_all(&d);
 }
 

crates/engine/src/variable_tests.rs

@@ -5,6 +5,79 @@ use serde_json::json;
 use crate::Session;
 use crate::params::id_of;
 
+fn stale_bound_color_document() -> (figcraft_doc::Document, figcraft_doc::NodeId) {
+    let mut s = Session::new();
+    let id = id_of(&s.execute("shape.rectangle", &json!({"x": 4000, "y": 4000, "width": 23, "height": 17})).unwrap()["id"]).unwrap();
+    let page = s.doc().unwrap().first_page().unwrap();
+    s.execute("variable.createCollection", &json!({"name": "Theme", "modes": ["Light", "Dark"]})).unwrap();
+    s.execute("variable.create", &json!({"collection": "Theme", "name": "surface", "type": "color", "value": "#FFFFFF"})).unwrap();
+    s.execute("variable.create", &json!({"collection": "Theme", "name": "size", "type": "number", "value": 23})).unwrap();
+    s.execute("variable.set", &json!({"variable": "surface", "mode": "Dark", "value": "#202124"})).unwrap();
+    s.execute("variable.set", &json!({"variable": "size", "mode": "Dark", "value": 99})).unwrap();
+    s.execute("variable.bind", &json!({"ids": [id], "field": "fill", "variable": "surface"})).unwrap();
+    s.execute("variable.bind", &json!({"ids": [id], "field": "width", "variable": "size"})).unwrap();
+    s.execute("variable.setMode", &json!({"collection": "Theme", "mode": "Dark"})).unwrap();
+    let mut doc = s.doc().unwrap().clone();
+    let node = doc.get_mut(id).unwrap();
+    node.name = "load-binding-sentinel".into();
+    node.fills = vec![figcraft_color::Paint::solid(figcraft_color::Color::WHITE)];
+    node.width = 5.0;
+    node.source = Some(page);
+    node.overrides.insert("sentinel".into());
+    doc.take_dirty();
+    (doc, id)
+}
+
+fn assert_dark_bound_color(doc: &figcraft_doc::Document, transform: figcraft_doc::geom::Affine) -> figcraft_doc::NodeId {
+    let node = doc.nodes().find(|n| n.name == "load-binding-sentinel").unwrap();
+    assert_eq!(node.fills.first().and_then(|p| p.solid_color()).map(|c| c.to_hex()), Some("202124".into()));
+    assert_eq!((node.transform, node.width, node.height), (transform, 5.0, 17.0));
+    assert!(node.bound.contains_key("fills/0/color") || node.bound.contains_key("fill"));
+    node.id
+}
+
+#[test]
+fn initial_color_bindings_settle_in_constructor_and_loaders() {
+    let (stale, _id) = stale_bound_color_document();
+    let name_transform = stale.nodes().find(|n| n.name == "load-binding-sentinel").unwrap().transform;
+
+    let mut state = Session::with_document(stale.clone());
+    let id = assert_dark_bound_color(state.doc().unwrap(), name_transform);
+    assert_eq!(state.doc().unwrap().node(id).unwrap().source, stale.first_page());
+    assert!(state.doc().unwrap().node(id).unwrap().overrides.contains("sentinel"));
+    assert!(!state.ds().unwrap().is_dirty());
+    assert!(state.doc().unwrap().dirty().is_empty());
+    assert_eq!(state.undo_depth(), (0, 0));
+    state.execute("shape.rectangle", &json!({"x": 0, "y": 0, "width": 2, "height": 2})).unwrap();
+    assert_dark_bound_color(state.doc().unwrap(), name_transform);
+
+    let native = figcraft_format::save_bytes(&stale, None).unwrap();
+    let (loaded, _) = crate::cmd::file::load_bytes(&native, "bindings.figcraft").unwrap();
+    // A native file settles when it opens as a document, not in the loader.
+    let opened = Session::with_document(loaded);
+    let loaded = opened.doc().unwrap();
+    let loaded_id = assert_dark_bound_color(loaded, name_transform);
+    assert_eq!(loaded_id, id);
+    assert_eq!(loaded.node(id).unwrap().source, stale.first_page());
+    assert!(loaded.node(id).unwrap().overrides.contains("sentinel"));
+    assert!(loaded.dirty().is_empty());
+
+    let (fig, _) = figcraft_format::fig::export(&stale, None).unwrap();
+    let (loaded, _) = crate::cmd::file::load_bytes(&fig, "bindings.fig").unwrap();
+    assert_dark_bound_color(&loaded, name_transform);
+}
+
+#[test]
+fn initial_paint_settlement_preserves_existing_dirty_nodes() {
+    let (mut doc, _) = stale_bound_color_document();
+    let page = doc.first_page().unwrap();
+    doc.mark_dirty([page]);
+
+    crate::cmd::styles::apply_paint_bindings_on_load(&mut doc);
+
+    assert_eq!(doc.dirty().iter().copied().collect::<Vec<_>>(), [page]);
+}
+
 #[test]
 fn bound_layers_follow_variable_values_and_unbind() {
     let mut s = Session::new();