M3: a layer binds an effect's field only when its effect has it

`variable.bind` on a layer checked only the variable's type against the
field's scope, so `effects/0/refraction` on a drop shadow, or a binding on
an effect the layer doesn't have (`effects/9/radius`), was kept and did
nothing. An effect style already refuses both. The layer now uses the same
check: effect `i` must exist and have the field, and the field's type
comes from that effect. A binding an older file has on such a field still
does nothing, and still unbinds.

ROADMAP.md

@@ -2,7 +2,7 @@
 
 **Stage: alpha** · next: beta, ~26 points and ~162–292 h away (one Opus 5.5 agent; ~33–67 h wall-clock with 5 agents)
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-02 · **Change:** minor (glass bends towards its core, and rounded rectangles work it out in closed form; glass's light is a line on its bevel and splay turns the bend towards the centre; glass bends with a thick-lens profile and splits its colours over 8 steps; glass effects take variables and keep their frost within 0–100; web host bridge: `?host=parent` or `data-host="page"` hands a page the app's files, documented in the hosting guide; a connector end moved with Cmd/Ctrl held goes on any part of an object, and stays there as the object moves or resizes; a tap on a plugin panel's button keeps what was typed in its fields; a Dash cap setting (none, round or square) on Dash and Custom strokes, drawn on both ends of every dash; library analytics list how many layers and files use each style and variable; the Controller menu names each button as PlayStation and Switch controllers do; widgets draw lines and SVG pictures (plugin API 6); a connector end dropped along a side of a shape attaches to that side (#1708); regression tests pin a rounded shape's one-sided stroke and SVG ids and font families without XML-forbidden characters (#1351, #1124); a damaged image is refused with a reason instead of showing as an empty box (#1474); an image copied in another app pastes again on the desktop, and in the browser for the first time (#492); SwiftUI and Compose code names a bound variable by its iOS or Android code syntax; the colour picker's Image tab shows a placeholder and Upload from computer, an asset preview, and a file dropped on it replaces the image, keeping the fill mode, crop and position (#1682); the Frame tool's Phone presets have the iPhone 17 family (#1691); Show in folder works in the Flatpak build and selects the file on Linux (#1701); a dashed line starts and ends with a half-length dash, on the canvas and in exports; the Pages, Layers and Assets search fields keep their text in the middle of the field (#1703); a board connector's path can be reshaped by dragging its path handles (#1710); boards have 16 more shapes (arrows, polygons, star, plus and flowchart symbols), in pickers that lay them out in a grid; library analytics count insertions and show insertions and detachments over the past 30 days, 90 days or year; a stroke's Custom style takes a dash pattern of any length as a comma-separated list (#1681); a control request can set its own timeout, up to 10 minutes (`timeoutMs`; `figcraft-cli mcp --attach PORT --timeout SECONDS`) (#1696); gap 6: a widget opens its plugin's panel (plugin API 5), whose callbacks redraw it; the keyboard's Menu key opens the context menu, as Shift+F10 does; an Open link action can open in place of the prototype, with "Open in new tab" off (gap 15); a collection of this file can be extended (Extend collection on its row, `variable.extendCollection`), its extension following its edits at once, and extended collections extend again in the file; the eyedropper with Cmd/Ctrl+Shift makes a colour style or variable of what it picks; a live session's welcome sends the document compressed to clients that read it, about seven times smaller (#1665); a control request that times out says truthfully whether it was dropped or is still running and will take effect, and only screenshots and input blame the window (#1673); a board keeps earlier votes' results, listed newest first in Results and deleted one at a time; the object a stamp will stick to is outlined while the stamp tool is over it or a stamp is dragged over it, and board objects take no drops (gap 24); a server can list the files shared from it now for everyone who reaches it, Home ▸ Online shows them and their links carry no secret (`team_files`, part of #742); team library analytics count detached instances per component and file (gap 10); skipping the Open link notice by command is saved with the preferences at once (gap 15); a selected connector's bar on a board sets its start and end points, solid or dashed, its weight and any colour (#1596); cells copied from a spreadsheet paste onto a board as a table; a long layer name stays on one line in the Export button and the Dev Mode header, ending with an ellipsis, and no longer covers the Design panel (#1650); with hundreds of layers selected, the Design panel and the selection overlays stop going over the whole selection on every frame, so dragging 648 layers averages about 1.1 ms of UI per frame (#1571); plugin panels show pictures: an `image` control, base64 within 256 KB and 4,096 px a side, named by its label (gap 6); `.fig` connector labels without a saved snapshot are kept, centred on their line (gap 1); a drag moving many layers re-runs only what sits around them, not each layer's bindings, sizing, text and instance checks, on every move (#1571); damaged font tracking table offsets are checked instead of wrapping on 32-bit targets, and font indexing makes its existing offset bounds explicit (#1125); BLine truncated
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-06 · **Change:** minor (a layer's effect binding takes only a field its effect has; glass bends towards its core, and rounded rectangles work it out in closed form; glass's light is a line on its bevel and splay turns the bend towards the centre; glass bends with a thick-lens profile and splits its colours over 8 steps; glass effects take variables and keep their frost within 0–100; web host bridge: `?host=parent` or `data-host="page"` hands a page the app's files, documented in the hosting guide; a connector end moved with Cmd/Ctrl held goes on any part of an object, and stays there as the object moves or resizes; a tap on a plugin panel's button keeps what was typed in its fields; a Dash cap setting (none, round or square) on Dash and Custom strokes, drawn on both ends of every dash; library analytics list how many layers and files use each style and variable; the Controller menu names each button as PlayStation and Switch controllers do; widgets draw lines and SVG pictures (plugin API 6); a connector end dropped along a side of a shape attaches to that side (#1708); regression tests pin a rounded shape's one-sided stroke and SVG ids and font families without XML-forbidden characters (#1351, #1124); a damaged image is refused with a reason instead of showing as an empty box (#1474); an image copied in another app pastes again on the desktop, and in the browser for the first time (#492); SwiftUI and Compose code names a bound variable by its iOS or Android code syntax; the colour picker's Image tab shows a placeholder and Upload from computer, an asset preview, and a file dropped on it replaces the image, keeping the fill mode, crop and position (#1682); the Frame tool's Phone presets have the iPhone 17 family (#1691); Show in folder works in the Flatpak build and selects the file on Linux (#1701); a dashed line starts and ends with a half-length dash, on the canvas and in exports; the Pages, Layers and Assets search fields keep their text in the middle of the field (#1703); a board connector's path can be reshaped by dragging its path handles (#1710); boards have 16 more shapes (arrows, polygons, star, plus and flowchart symbols), in pickers that lay them out in a grid; library analytics count insertions and show insertions and detachments over the past 30 days, 90 days or year; a stroke's Custom style takes a dash pattern of any length as a comma-separated list (#1681); a control request can set its own timeout, up to 10 minutes (`timeoutMs`; `figcraft-cli mcp --attach PORT --timeout SECONDS`) (#1696); gap 6: a widget opens its plugin's panel (plugin API 5), whose callbacks redraw it; the keyboard's Menu key opens the context menu, as Shift+F10 does; an Open link action can open in place of the prototype, with "Open in new tab" off (gap 15); a collection of this file can be extended (Extend collection on its row, `variable.extendCollection`), its extension following its edits at once, and extended collections extend again in the file; the eyedropper with Cmd/Ctrl+Shift makes a colour style or variable of what it picks; a live session's welcome sends the document compressed to clients that read it, about seven times smaller (#1665); a control request that times out says truthfully whether it was dropped or is still running and will take effect, and only screenshots and input blame the window (#1673); a board keeps earlier votes' results, listed newest first in Results and deleted one at a time; the object a stamp will stick to is outlined while the stamp tool is over it or a stamp is dragged over it, and board objects take no drops (gap 24); a server can list the files shared from it now for everyone who reaches it, Home ▸ Online shows them and their links carry no secret (`team_files`, part of #742); team library analytics count detached instances per component and file (gap 10); skipping the Open link notice by command is saved with the preferences at once (gap 15); a selected connector's bar on a board sets its start and end points, solid or dashed, its weight and any colour (#1596); cells copied from a spreadsheet paste onto a board as a table; a long layer name stays on one line in the Export button and the Dev Mode header, ending with an ellipsis, and no longer covers the Design panel (#1650); with hundreds of layers selected, the Design panel and the selection overlays stop going over the whole selection on every frame, so dragging 648 layers averages about 1.1 ms of UI per frame (#1571); plugin panels show pictures: an `image` control, base64 within 256 KB and 4,096 px a side, named by its label (gap 6); `.fig` connector labels without a saved snapshot are kept, centred on their line (gap 1); a drag moving many layers re-runs only what sits around them, not each layer's bindings, sizing, text and instance checks, on every move (#1571); damaged font tracking table offsets are checked instead of wrapping on 32-bit targets, and font iLine truncated
 
 FigCraft is a clean-room, open-source, pure-Rust reimplementation of the Figma design workflow,
 native on macOS, Windows, Linux and FreeBSD and in the browser, fully drivable by agents through
@@ -358,6 +358,7 @@ Ranked; detail and milestones in [`docs/roadmap.md`](docs/roadmap.md).
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-11-06 | patch | M3: a layer's effect binding (`variable.bind`, `effects/<i>/<field>`) takes only a field its effect has, as an effect style's does: `effects/0/refraction` on a drop shadow, or a binding on an effect the layer doesn't have, is refused instead of being kept and doing nothing (a binding an older file has there still does nothing, and unbinds). Tests: `binding_lists_tests::a_layer_binds_only_fields_its_effects_have`. Numbers unchanged |
 | 2026-11-02 | patch | M8, #1885: a glass whose shape is too big to keep whole at the zoom (past `MAX_SHAPE_PX` with its core's margin) bends along its edge normals instead of working out a core, so its fields never cover more pixels than a kept shape's, and the core's feature transform holds 16 bytes a pixel. The edge normals are box-blurred twice again and the bend directions once, as documented. Test: `glass::tests::a_shape_too_big_to_keep_bends_along_its_normals`. Numbers unchanged |
 | 2026-11-02 | minor | M3, #1885: glass bends the backdrop towards its core, the shape shrunk by `depth` and the bevel, as the reference tool's: round a sharp corner the bend turns smoothly instead of meeting along the diagonal, and a part thinner than twice that (a capsule, a letter's stroke) bends across itself towards its own middle (pixels about as deep as any within 2 px). Rectangles, frames, components, instances and sections whose corners aren't smoothed work their glass out in closed form, with nothing to rasterise, transform or keep: a zoom frame draws in 40 ms instead of 54 and a resize frame in 46 instead of 67 (`glass_render_timings`, release, 2×). Other shapes keep their fields, with the bend directions for the last two depths asked for beside them, so dragging the Depth slider works out only those again. Tests: `glass::tests::a_sharp_corner_bends_round_towards_the_core`, `glass::tests::a_thin_part_bends_across_itself`, `glass::tests::neighbouring_strokes_bend_towards_their_own_middles`, `glass::tests::a_rounded_rectangle_in_closed_form_matches_its_distance_transform`, `glass_cut_tests::what_the_shape_depends_on_works_it_out_again_and_nothing_else_does`. Numbers unchanged |
 | 2026-11-02 | minor | M3, #1885: glass's light is a line on its 1-unit bevel added to the backdrop, as the reference tool's: fully where the edge faces the light, none below 0.35 of facing it and 0.6 as much on the opposite side, with a faint gradient across the curve, 5% darker facing the light and lighter opposite (it was a glow mixed towards white, as deep as `splay` made it). `splay` turns the bend from along the edge's normal towards the way away from the layer's centre, as the reference tool's does, and no longer widens the light: files with a splay above 0 look different. The direction to the centre is worked out in the shape's own frame, so cut renders match. Tests: `glass::tests::the_light_lies_on_the_bevel_and_the_gradient_across_the_curve`, `backdrop_tests::splay_turns_the_bend_towards_the_centre`, `glass_cut_tests::the_light_is_a_line_on_the_bevel`. Numbers unchanged |

crates/engine/src/assets/style_vars.rs

@@ -29,13 +29,7 @@ pub fn field_type(kind: &StyleKind, key: &str) -> Option<VariableType> {
             };
             ok.then_some(Color)
         }
-        (StyleKind::Effect { effects }, Some((BoundList::Effects, i, field))) => match (&effects.get(i)?.kind, field) {
-            (EffectKind::DropShadow(_) | EffectKind::InnerShadow(_), "color") => Some(Color),
-            (EffectKind::DropShadow(_) | EffectKind::InnerShadow(_), "radius" | "spread" | "offsetX" | "offsetY") => Some(Number),
-            (EffectKind::LayerBlur(_) | EffectKind::BackgroundBlur(_), "radius" | "startRadius") => Some(Number),
-            (EffectKind::Glass(_), f) if figcraft_doc::Glass::BOUND_FIELDS.contains(&f) => Some(Number),
-            _ => None,
-        },
+        (StyleKind::Effect { effects }, Some((BoundList::Effects, i, field))) => effect_field_type(&effects.get(i)?.kind, field),
         (StyleKind::Grid { grids }, Some((BoundList::Grids, i, "size" | "count" | "gutter" | "offset"))) => grids.get(i).map(|_| Number),
         (StyleKind::Text { .. }, None) => match key {
             "fontSize" | "lineHeight" | "letterSpacing" => Some(Number),
@@ -46,6 +40,19 @@ pub fn field_type(kind: &StyleKind, key: &str) -> Option<VariableType> {
     }
 }
 
+/// The type of variable an effect of `kind` takes on `field` (the last part of an
+/// `effects/<i>/<field>` key), on a layer or in an effect style; None when it has no such field.
+pub fn effect_field_type(kind: &EffectKind, field: &str) -> Option<VariableType> {
+    use VariableType::{Color, Number};
+    match (kind, field) {
+        (EffectKind::DropShadow(_) | EffectKind::InnerShadow(_), "color") => Some(Color),
+        (EffectKind::DropShadow(_) | EffectKind::InnerShadow(_), "radius" | "spread" | "offsetX" | "offsetY") => Some(Number),
+        (EffectKind::LayerBlur(_) | EffectKind::BackgroundBlur(_), "radius" | "startRadius") => Some(Number),
+        (EffectKind::Glass(_), f) if figcraft_doc::Glass::BOUND_FIELDS.contains(&f) => Some(Number),
+        _ => None,
+    }
+}
+
 /// The variable scopes a picker offers for `key` of a style of `kind`: a variable scoped to any one
 /// of them fits. A paint style's colors take fill and stroke variables, an effect style's fields
 /// take effect variables, and a text style's fields take the variables of their font property.

crates/engine/src/binding_lists_tests.rs

@@ -129,6 +129,37 @@ fn glass_fields_take_number_variables() {
     assert!(s.execute("style.bind", &json!({"style": fx, "field": "effects/0/spread", "variable": "large"})).is_err(), "glass has no spread");
 }
 
+#[test]
+fn a_layer_binds_only_fields_its_effects_have() {
+    let (mut s, r) = setup();
+    ex(&mut s, "effect.add", json!({"ids": [r], "type": "dropShadow"}));
+    ex(&mut s, "effect.add", json!({"ids": [r], "type": "glass"}));
+    // As an effect style does: a drop shadow has no refraction, glass no spread, and there is no
+    // effect 5. Nothing is bound.
+    for (field, var, says) in [
+        ("effects/0/refraction", "large", "no field"),
+        ("effects/1/spread", "large", "no field"),
+        ("effects/5/radius", "large", "no field"),
+        ("effects/1/lightAngle", "brand", "doesn't take a color variable"),
+        ("effects/0/color", "large", "doesn't take a number variable"),
+    ] {
+        let e = s.execute("variable.bind", &json!({"ids": [r], "field": field, "variable": var})).unwrap_err().to_string();
+        assert!(e.contains(says), "{field} ← {var}: {e}");
+    }
+    assert!(s.doc().unwrap().node(r).unwrap().bound.is_empty());
+    // The fields each effect has still bind.
+    ex(&mut s, "variable.bind", json!({"ids": [r], "field": "effects/0/spread", "variable": "small"}));
+    ex(&mut s, "variable.bind", json!({"ids": [r], "field": "effects/1/refraction", "variable": "large"}));
+    assert_eq!(s.doc().unwrap().node(r).unwrap().bound.len(), 2);
+    // A binding an older file already has on a field its effect lacks does nothing, and unbinds.
+    let large = s.doc().unwrap().variables.get("large").unwrap().id.clone();
+    s.doc_mut().unwrap().get_mut(r).unwrap().bound.insert("effects/0/refraction".into(), large);
+    ex(&mut s, "variable.set", json!({"variable": "large", "value": 40}));
+    assert!(matches!(&s.doc().unwrap().node(r).unwrap().effects[0].kind, EffectKind::DropShadow(_)));
+    ex(&mut s, "variable.bind", json!({"ids": [r], "field": "effects/0/refraction"}));
+    assert!(!s.doc().unwrap().node(r).unwrap().bound.contains_key("effects/0/refraction"));
+}
+
 fn ex_value(s: &mut Session, cmd: &str, p: serde_json::Value) -> serde_json::Value {
     s.execute(cmd, &p).unwrap_or_else(|e| panic!("{cmd}: {e}"))
 }

crates/engine/src/cmd/styles.rs

@@ -788,6 +788,9 @@ pub(crate) fn bind_variable(cmd: &str, doc: &mut Document, ids: &[NodeId], field
         for i in ids {
             match field.strip_prefix(crate::components::PROP_BINDING) {
                 Some(name) => super::component::check_prop_binding(doc, *i, name, v.kind).map_err(|e| bad(cmd, e))?,
+                None if !super::variables::has_field(doc, *i, field) => {
+                    return Err(bad(cmd, format!("the layer has no field `{field}` to bind")));
+                }
                 None if !super::variables::field_takes(doc, *i, field, v.kind) => {
                     return Err(bad(cmd, format!("`{field}` doesn't take a {} variable", v.kind.id())));
                 }

crates/engine/src/cmd/variables.rs

@@ -654,10 +654,28 @@ pub fn field_scope(doc: &Document, node: NodeId, field: &str) -> Option<&'static
     })
 }
 
+/// The type of variable effect `i` of `node` takes on `field`, as an effect style's does: None when
+/// the layer has no effect `i` or that effect has no such field.
+fn effect_field(doc: &Document, node: NodeId, i: usize, field: &str) -> Option<VariableType> {
+    crate::style_vars::effect_field_type(&doc.node(node)?.effects.get(i)?.kind, field)
+}
+
+/// Whether `node` has the field a binding key names. Only effect fields are checked: a layer has
+/// `effects/<i>/<field>` when its effect `i` has that field (a drop shadow has no `refraction`).
+pub fn has_field(doc: &Document, node: NodeId, field: &str) -> bool {
+    match super::lists::list_binding(field) {
+        Some((BoundList::Effects, i, f)) => effect_field(doc, node, i, f).is_some(),
+        _ => true,
+    }
+}
+
 /// Whether property `field` of `node` takes a variable of type `kind`: the type its scope belongs
 /// to (number variables also fill text content), booleans for visibility, numbers for layout grid
-/// fields; fields without a known type take any.
+/// fields, an effect's field the type its effect takes there; fields without a known type take any.
 pub fn field_takes(doc: &Document, node: NodeId, field: &str, kind: VariableType) -> bool {
+    if let Some((BoundList::Effects, i, f)) = super::lists::list_binding(field) {
+        return effect_field(doc, node, i, f) == Some(kind);
+    }
     match (field, field_scope(doc, node, field)) {
         ("visible", _) => kind == VariableType::Boolean,
         (_, Some(scope)) => scope_known(kind, scope),

crates/engine/src/variable_tests.rs

@@ -172,7 +172,8 @@ fn effects_follow_their_variables() {
     bind(&mut s, "effects/0/offsetY", "y");
     bind(&mut s, "effects/0/color", "shadow");
     bind(&mut s, "effects/1/radius", "blur");
-    bind(&mut s, "effects/9/radius", "blur");
+    // There is no effect 9 to bind (see `binding_lists_tests::a_layer_binds_only_fields_its_effects_have`).
+    assert!(s.execute("variable.bind", &json!({"ids": [r], "field": "effects/9/radius", "variable": "blur"})).is_err());
     let fx = |s: &Session| s.doc().unwrap().node(r).unwrap().effects.clone();
     match &fx(&s)[0].kind {
         figcraft_doc::EffectKind::DropShadow(sh) => {

docs/components-parity.md

@@ -1,6 +1,6 @@
 # Components, variants, styles and variables parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-02 · **Change:** minor (glass effects take variables; Delete on a layer inside an instance hides it as an override instead of being refused, as the help center says: "Figma will only toggle the layer's visibility instead of removing it"; library analytics list how many layers and files use each style and variable; SwiftUI and Compose code names a bound variable by its iOS or Android code syntax; library analytics count insertions and show insertions and detachments over the past 30 days, 90 days or year; a collection of this file can be extended (Extend collection on its row, `variable.extendCollection`), its extension following its edits at once, and extended collections extend again in the file; a typed or stored variable, collection or mode id names only the object with that id (#1613); colour variables can be calculated from other colours per mode — `{alpha}` replaces a colour's alpha, `{mix}` blends two — and follow them (#1280); stored variable and collection references keep their identity when another object is named like their id (follow-up to #1542); a component set's property rows fit the 240 px right panel: variant values wrap two to a line there and every + and − stays in view; opening a file contacts no team library server it names until you check it (#1097); an explicit variables file path (`variable.import`, the `variables` of `file.open` and `file.import`) is refused past 256 MiB or when it isn't a regular file, as the sibling `variables.json` already was (part of #1114); component properties keep the order they were made in when one is renamed, and Make slot asks for the slot's name first (#1536, #1537); components can't contain their own instances, directly or through others (#1084); the instance-swap menus have a search field (#1338); an instance-swap property's default menu scrolls (#1338); variables on a text style's fields from the style editor; instance-swap properties in the component playground; duplicating or Alt-dragging a main component makes an instance of it (#892); a bound colour variable's alpha applies once (#802); variables import reads `variables` outside `meta` and warns when it imports none (#790); variant properties reorder by drag; library files saved right after a read are read again; Hide when publishing note corrected; size and resizing overrides of layers inside instances (#731); variables export in the browser as a download; core editor leftovers: component playground, variables inside styles; layers and assets panels behaviour suite and fixes; extended collections tail; styles and variables behaviour suite and fixes; components behaviour suite and fixes; team libraries on the server, library usage and swapping a library; extended collections, variables import/export, gradient stops and variant properties bound to variables) · **Target:** Figma Design (desktop app 126.10.7)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-06 · **Change:** minor (a layer's effect binding takes only a field its effect has; glass effects take variables; Delete on a layer inside an instance hides it as an override instead of being refused, as the help center says: "Figma will only toggle the layer's visibility instead of removing it"; library analytics list how many layers and files use each style and variable; SwiftUI and Compose code names a bound variable by its iOS or Android code syntax; library analytics count insertions and show insertions and detachments over the past 30 days, 90 days or year; a collection of this file can be extended (Extend collection on its row, `variable.extendCollection`), its extension following its edits at once, and extended collections extend again in the file; a typed or stored variable, collection or mode id names only the object with that id (#1613); colour variables can be calculated from other colours per mode — `{alpha}` replaces a colour's alpha, `{mix}` blends two — and follow them (#1280); stored variable and collection references keep their identity when another object is named like their id (follow-up to #1542); a component set's property rows fit the 240 px right panel: variant values wrap two to a line there and every + and − stays in view; opening a file contacts no team library server it names until you check it (#1097); an explicit variables file path (`variable.import`, the `variables` of `file.open` and `file.import`) is refused past 256 MiB or when it isn't a regular file, as the sibling `variables.json` already was (part of #1114); component properties keep the order they were made in when one is renamed, and Make slot asks for the slot's name first (#1536, #1537); components can't contain their own instances, directly or through others (#1084); the instance-swap menus have a search field (#1338); an instance-swap property's default menu scrolls (#1338); variables on a text style's fields from the style editor; instance-swap properties in the component playground; duplicating or Alt-dragging a main component makes an instance of it (#892); a bound colour variable's alpha applies once (#802); variables import reads `variables` outside `meta` and warns when it imports none (#790); variant properties reorder by drag; library files saved right after a read are read again; Hide when publishing note corrected; size and resizing overrides of layers inside instances (#731); variables export in the browser as a download; core editor leftovers: component playground, variables inside styles; layers and assets panels behaviour suite and fixes; extended collections tail; styles and variables behaviour suite and fixes; components behaviour suite and fixes; team libraries on the server, library usage and swapping a library; extended collections, variables import/export, gradient stops and variant properties bound to variables) · **Target:** Figma Design (desktop app 126.10.7)
 
 Design systems are why teams adopt Figma. **Components: breadth ~96%, ready ~72%. Styles and
 variables: breadth ~95%, ready ~76% (estimated).** QA'd with a synthetic design system of ~300
@@ -67,7 +67,7 @@ updates with overrides kept: `library_tests.rs`, `components_scale_tests.rs`.
 | Modes: add, duplicate, rename, delete, set as default / reorder | done | layers on Auto follow a new default; explicit modes stay |
 | Deleting a bound variable or its collection | done | layers keep their last value and are unbound; aliases to it take its values and colour calculations reading it keep the colour they show |
 | Code syntax per platform (Web, iOS, Android) | done | generated CSS uses the Web name, SwiftUI the iOS one and Compose the Android one (a variable without one keeps its value there); in the variables JSON; ArkUI and Flutter have no platform of their own and write values |
-| Bindings: fills, strokes, effects, opacity, padding, gaps, sizes, radius, font family/style, font size/weight, line height, letter spacing, paragraph spacing/indent, text, visibility, layout grids, instance properties | done | type-checked per field; glass fields too (light angle, intensity, refraction, depth, dispersion, frost and splay, percentages as the Design panel shows them); number variables fill text content; the Design panel's font family and font style menus start with Apply variable (string variables), and a bound one shows its variable in place of the menu; a colour variable bound to a solid paint brings its whole colour, alpha included, once (the paint's opacity restarts at 100% on binding, an opacity set while bound multiplies on top; unbinding moves the alpha back into the opacity) |
+| Bindings: fills, strokes, effects, opacity, padding, gaps, sizes, radius, font family/style, font size/weight, line height, letter spacing, paragraph spacing/indent, text, visibility, layout grids, instance properties | done | type-checked per field, an effect's only where its effect has the field (as in effect styles); glass fields too (light angle, intensity, refraction, depth, dispersion, frost and splay, percentages as the Design panel shows them); number variables fill text content; the Design panel's font family and font style menus start with Apply variable (string variables), and a bound one shows its variable in place of the menu; a colour variable bound to a solid paint brings its whole colour, alpha included, once (the paint's opacity restarts at 100% on binding, an opacity set while bound multiplies on top; unbinding moves the alpha back into the opacity) |
 | Explicit modes per frame, library collections' modes | done | stored variable and collection references resolve by exact id in export, library copies and swaps, imported aliases, alias deletion and cycle checks, Dev Inspect, the library mode picker and prototype playback; a collection or variable named like another's id no longer stands in for it there |
 | Gradient stops and variant properties bound to variables | done | a stop's binding follows it when earlier stops are removed |
 | Extended collections | done | this file's collections (Extend collection on a collection's row; following its edits at once, chains included) and library collections, including a library's own extended collections (chains through libraries); overrides per mode with reset; follow library updates, variables new to the library collection being an update of their own; modes inherited. Checked with synthetic libraries only ([gaps](gaps.md) #14) |
@@ -78,6 +78,7 @@ updates with overrides kept: `library_tests.rs`, `components_scale_tests.rs`.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-11-06 | patch | M3: a layer's effect binding (`variable.bind`, `effects/<i>/<field>`) takes only a field its effect has, as an effect style's does: `effects/0/refraction` on a drop shadow, or a binding on an effect the layer doesn't have, is refused instead of being kept and doing nothing (a binding an older file has there still does nothing, and unbinds). Tests: `binding_lists_tests::a_layer_binds_only_fields_its_effects_have`. Grade unchanged. |
 | 2026-11-02 | minor | M3, #1885: glass effects take variables, as the reference tool's do: its light angle, intensity, refraction, depth, dispersion, frost and splay bind to number variables on a layer (`variable.bind`, `effects/<i>/<lightAngle\|lightIntensity\|refraction\|depth\|dispersion\|radius\|splay>`, `radius` being the frost) and in an effect style (`style.bind`), and the Design panel's glass fields take a variable like the shadow and blur fields. A variable reads as the field shows it: intensity, refraction, dispersion and splay in percent. Tests: `binding_lists_tests::glass_fields_take_number_variables`, `effects_tests::glass_fields_take_bound_numbers_as_the_panel_shows_them`. Grade unchanged. |
 | 2026-11-01 | patch | M3: Delete on a layer inside an instance hides it (an override) instead of being refused ("You can't delete a layer or object from an instance. If you try, Figma will only toggle the layer's visibility instead of removing it", Guide to auto layout); `edit.delete` reports those ids under `hidden`, the structure and the main component stay as they were, one undo step; deleting the instance itself still removes it. Found by a documentation audit of the auto layout page. Test: `components_behaviour_tests::deleting_a_layer_inside_an_instance_hides_it_instead` (the refusal row for it is gone from `what_instances_cannot_override_is_refused`). Numbers unchanged |
 | 2026-10-31 | minor | M3, gap 10: library analytics cover styles and variables. A file reports how many of its layers use each of a library's styles and variables, and Show usage (`library.usage`) lists them beside the components, by a Type choice, with their layers and files. Layers inside instances count for their component. Insertions, detachments and modes aren't counted for them yet. Numbers unchanged. Tests: `library_assets_tests`. |