Merge pull request #2046 from StrajnarFilip/claude/fix-2026-merge-layout-conflicts

M9: one auto layout edit on each side of a branch is one conflict (#2026)

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:** 2026-11-06 · **Change:** minor (the boolean operation menu leads each entry with an original icon (#2003); glass takes one sample instead of its dispersion window where the colours split under 1/256 px; 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 Line truncated
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-06 · **Change:** minor (; the boolean operation menu leads each entry with an original icon (#2003); glass takes one sample instead of its dispersion window where the colours split under 1/256 px; 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 everLine 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
@@ -359,6 +359,7 @@ Ranked; detail and milestones in [`docs/roadmap.md`](docs/roadmap.md).
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-11-06 | patch | M9, #2026: a branch merge counts one conflict per auto layout field changed both ways, not one for every size and place auto layout works out from it; values an instance takes from its main no longer conflict, and auto layout settings changed one way survive a conflict on another field. Tests: `branch_tests::one_conflicting_auto_layout_edit_is_one_conflict`, `branch_tests::auto_layout_fields_changed_one_way_survive_a_conflict`, `branch_tests::sizes_auto_layout_works_out_never_conflict`. Numbers unchanged |
 | 2026-11-06 | patch | M8: glass takes one backdrop sample instead of its 18-sample dispersion window where the colours split under 1/256 px (the flat end of the curve, where the move is short), within one level of the window over any backdrop: a large pane renders about 2–5% faster, with the same pixels in the renders compared. Tests: `glass::tests::a_split_too_narrow_to_show_takes_one_sample`. 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 |

crates/collab/src/merge.rs

@@ -9,16 +9,20 @@
 //! interactions, accessibility annotations, Dev Mode resources and measurements) merge item by
 //! item: both sides changing different items of the list (or one adding items at its end) is no
 //! conflict, only the same item changed both ways or the list shortened on a side while the other
-//! changed it. Nothing that conflicts is merged until it is resolved: each conflict is resolved for
-//! one side, and the other side's changes to it are left out. Everything else from both sides is
-//! kept.
+//! changed it. Auto layout settings (a frame's and a child's) merge field by field: each field
+//! changed both ways is a conflict of its own, and the other fields merge. Values a file works out
+//! for itself (a size or place auto layout gives a layer, text sizing to its characters, a value a
+//! layer in an instance takes from its main component) never conflict: the merged file works them
+//! out again from what they follow. Nothing that conflicts is merged until it is resolved: each
+//! conflict is resolved for one side, and the other side's changes to it are left out. Everything
+//! else from both sides is kept.
 
 use std::collections::{BTreeMap, BTreeSet};
 use std::fmt;
 
-use figcraft_doc::{Document, NodeId};
+use figcraft_doc::{Document, Node, NodeId, NodeKind, Sizing, TextAutoResize};
 use serde::{Deserialize, Serialize};
-use serde_json::Value;
+use serde_json::{Map, Value};
 
 use crate::change::{Change, DocProp, Entry, Json, Prop};
 use crate::replica::{Mode, Positions, Replica, create_change};
@@ -33,6 +37,7 @@ pub enum Side {
 }
 
 impl Side {
+    /// The side that isn't `self`.
     pub fn other(self) -> Side {
         match self {
             Side::Branch => Side::Main,
@@ -48,6 +53,7 @@ impl Side {
         }
     }
 
+    /// The side `"branch"` or `"main"` names (`None` for anything else).
     pub fn parse(s: &str) -> Option<Side> {
         match s {
             "branch" => Some(Side::Branch),
@@ -62,6 +68,9 @@ impl Side {
 pub enum Key {
     /// A layer property. A layer's parent and position are one property (where it is).
     Node(NodeId, Prop),
+    /// One field of a layer property that merges field by field ([`PER_FIELD`]): `padding` of
+    /// `layout`, `sizing_h` of `childLayout`…
+    Field(NodeId, Prop, String),
     /// A layer deleted on one side and edited (it or what's inside it) on the other.
     Layer(NodeId),
     /// A document-level property.
@@ -78,11 +87,13 @@ fn camel<T: Serialize>(v: &T) -> String {
     }
 }
 
-/// `12/fills`, `12/layer`, `doc/styleOrder`, `style/S:3`, `comment/7`… (the keys resolutions use).
+/// `12/fills`, `12/layout.padding`, `12/layer`, `doc/styleOrder`, `style/S:3`, `comment/7`… (the
+/// keys resolutions use).
 impl fmt::Display for Key {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Key::Node(id, prop) => write!(f, "{id}/{}", camel(prop)),
+            Key::Field(id, prop, field) => write!(f, "{id}/{}.{field}", camel(prop)),
             Key::Layer(id) => write!(f, "{id}/layer"),
             Key::Doc(prop) => write!(f, "doc/{}", camel(prop)),
             Key::Entry(e) => match e {
@@ -129,10 +140,25 @@ pub struct Plan {
     /// The main file's changes since the base.
     pub main: Vec<Change>,
     pub conflicts: Vec<Conflict>,
+    /// Layer properties changed both ways to values both files work out for themselves
+    /// ([`computed`]): no conflict, and a merge leaves the file merged into its own value.
+    derived: BTreeSet<Key>,
+    /// Layer properties ([`Key::Node`]) merged field by field with fields in conflict.
+    fields: BTreeMap<Key, Fields>,
     branch_positions: Positions,
     main_positions: Positions,
 }
 
+/// A layer property merged field by field ([`merge_fields`]): the value with every field changed
+/// one way (or the same way on both sides) merged, and each side's values of the fields changed
+/// both ways (`Null` for a field a side left out).
+#[derive(Clone, Debug, Default, PartialEq)]
+struct Fields {
+    merged: Map<String, Value>,
+    branch: Map<String, Value>,
+    main: Map<String, Value>,
+}
+
 /// Document-level properties that belong to each copy, not to the work: the file name (a branch
 /// is named after itself) and the page it opens on.
 fn merges(c: &Change) -> bool {
@@ -152,6 +178,7 @@ fn key_of(c: &Change) -> Option<Key> {
     })
 }
 
+/// The changes (indexes) in `changes` grouped by what they write ([`key_of`]).
 fn by_key(changes: &[Change]) -> BTreeMap<Key, Vec<usize>> {
     let mut out: BTreeMap<Key, Vec<usize>> = BTreeMap::new();
     for (i, c) in changes.iter().enumerate() {
@@ -193,6 +220,108 @@ fn merged_list(base: &Document, key: &Key, b: Option<&Change>, m: Option<&Change
     merge_items(o.0.as_array()?, bv.0.as_array()?, mv.0.as_array()?).map(|v| Json(Value::Array(v)))
 }
 
+/// Layer properties whose fields merge one by one: auto layout settings, a frame's (`layout`) and
+/// a child's (`childLayout`). Changing the padding on one side and the gap on the other is no
+/// conflict, and each field changed both ways is a conflict of its own ([`Key::Field`]).
+const PER_FIELD: &[Prop] = &[Prop::Layout, Prop::ChildLayout];
+
+/// Three-way merge of object `o` changed to `b` on one side and `m` on the other, field by field:
+/// a field changed on one side takes that side's value, and one changed both ways (differently)
+/// is in conflict. `None` when any of them isn't an object (auto layout added or removed).
+fn merge_fields(o: &Value, b: &Value, m: &Value) -> Option<Fields> {
+    let (o, b, m) = (o.as_object()?, b.as_object()?, m.as_object()?);
+    let names: BTreeSet<&String> = o.keys().chain(b.keys()).chain(m.keys()).collect();
+    let mut out = Fields::default();
+    for name in names {
+        let (base, x, y) = (o.get(name), b.get(name), m.get(name));
+        let kept = if x == base {
+            y
+        } else if y == base || x == y {
+            x
+        } else {
+            out.branch.insert(name.clone(), x.cloned().unwrap_or(Value::Null));
+            out.main.insert(name.clone(), y.cloned().unwrap_or(Value::Null));
+            base
+        };
+        if let Some(v) = kept {
+            out.merged.insert(name.clone(), v.clone());
+        }
+    }
+    Some(out)
+}
+
+/// Both sides' writes `b` and `m` of property `key` (one of [`PER_FIELD`]) merged field by field
+/// against the base; `None` when `key` isn't such a property or a value isn't an object.
+fn merged_fields(base: &Document, key: &Key, b: Option<&Change>, m: Option<&Change>) -> Option<Fields> {
+    let Key::Node(id, prop) = key else { return None };
+    let (Some(Change::Set { value: bv, .. }), Some(Change::Set { value: mv, .. })) = (b, m) else { return None };
+    if !PER_FIELD.contains(prop) {
+        return None;
+    }
+    let o = prop.get(base.node(*id)?).ok()?;
+    merge_fields(&o.0, &bv.0, &mv.0)
+}
+
+/// Whether layer `n` of `doc` is placed by its parent's auto layout (not absolute).
+fn in_flow(doc: &Document, n: &Node) -> bool {
+    !n.child_layout.absolute && n.parent.and_then(|p| doc.node(p)).is_some_and(|p| p.layout.is_some())
+}
+
+/// Whether auto layout or text works out layer `n`'s width (`horizontal`) or height: an auto layout
+/// frame hugging its contents, a child filling its auto layout parent, or text sizing to its
+/// characters.
+fn sized_for_itself(doc: &Document, n: &Node, horizontal: bool) -> bool {
+    let sizing = if horizontal { n.child_layout.sizing_h } else { n.child_layout.sizing_v };
+    let by_layout = match sizing {
+        Sizing::Hug => n.layout.is_some(),
+        Sizing::Fill => in_flow(doc, n),
+        Sizing::Fixed => false,
+    };
+    let by_text = match &n.kind {
+        NodeKind::Text(t) => t.auto_resize == TextAutoResize::WidthAndHeight || (!horizontal && t.auto_resize == TextAutoResize::Height),
+        _ => false,
+    };
+    by_layout || by_text
+}
+
+/// Whether layer `n` of `doc` (an instance, or a layer inside one) has property `prop` as its main
+/// component's layer has it: it follows the main rather than overriding it.
+fn follows_main(doc: &Document, n: &Node, prop: Prop) -> bool {
+    let main = match &n.kind {
+        NodeKind::Instance { component, .. } => Some(*component),
+        _ => n.source,
+    };
+    Prop::FIELDS.contains(&prop) && main.and_then(|m| doc.node(m)).is_some_and(|m| !prop.differs(n, m))
+}
+
+/// Whether layer property `key` holds a value `doc` works out for itself rather than one set on
+/// the layer: a size auto layout or text gives it ([`sized_for_itself`]), its place in an auto
+/// layout parent, or a value it takes from its main component ([`follows_main`]).
+fn computed(doc: &Document, key: &Key) -> bool {
+    let Key::Node(id, prop) = key else { return false };
+    let Some(n) = doc.node(*id) else { return false };
+    let by_layout = match prop {
+        Prop::Width => sized_for_itself(doc, n, true),
+        Prop::Height => sized_for_itself(doc, n, false),
+        Prop::Transform => in_flow(doc, n),
+        _ => false,
+    };
+    by_layout || follows_main(doc, n, *prop)
+}
+
+/// Whether property `key`, changed both ways, is one both files work out for themselves
+/// ([`computed`]), so neither side's value is a choice to make. A place given by auto layout is
+/// only that when both sides also turn and scale the layer the same way (a rotation is set on the
+/// layer, not worked out).
+fn derived_on_both(branch: &Document, main: &Document, key: &Key) -> bool {
+    if !(computed(branch, key) && computed(main, key)) {
+        return false;
+    }
+    let Key::Node(id, Prop::Transform) = key else { return true };
+    let linear = |doc: &Document| doc.node(*id).map(|n| n.transform.as_coeffs()).map(|c| [c[0], c[1], c[2], c[3]]);
+    linear(branch) == linear(main)
+}
+
 /// The change at the only index in `c`.
 fn only<'a>(c: &[usize], all: &'a [Change]) -> Option<&'a Change> {
     match c {
@@ -265,6 +394,8 @@ pub fn plan(base: &Document, branch: &Document, main: &Document) -> Result<Plan,
     let mut mc: Vec<Change> = m.changes.into_iter().filter(merges).collect();
     let mut conflicts = Vec::new();
     let mut lists = Vec::new();
+    let mut derived = BTreeSet::new();
+    let mut fields = BTreeMap::new();
     let km = by_key(&mc);
     for (k, bi) in by_key(&bc) {
         // Deletions conflict with edits (below); images are content-addressed, so never differ.
@@ -279,13 +410,28 @@ pub fn plan(base: &Document, branch: &Document, main: &Document) -> Result<Plan,
         if same {
             continue;
         }
-        match merged_list(base, &k, only(&bi, &bc), only(mi, &mc)) {
-            Some(value) => lists.push((bi, mi.clone(), value)),
-            None => conflicts.push(Conflict { key: k, deleted_by: None, branch: bi, main: mi.clone() }),
+        if derived_on_both(branch, main, &k) {
+            derived.insert(k);
+            continue;
+        }
+        if let Some(value) = merged_list(base, &k, only(&bi, &bc), only(mi, &mc)) {
+            lists.push((bi, mi.clone(), value));
+            continue;
+        }
+        match (&k, merged_fields(base, &k, only(&bi, &bc), only(mi, &mc))) {
+            (_, Some(f)) if f.branch.is_empty() => lists.push((bi, mi.clone(), Json(Value::Object(f.merged)))),
+            (Key::Node(id, prop), Some(f)) => {
+                for name in f.branch.keys() {
+                    let key = Key::Field(*id, *prop, name.clone());
+                    conflicts.push(Conflict { key, deleted_by: None, branch: bi.clone(), main: mi.clone() });
+                }
+                fields.insert(k, f);
+            }
+            _ => conflicts.push(Conflict { key: k, deleted_by: None, branch: bi, main: mi.clone() }),
         }
     }
-    // Both sides' writes of a list merged item by item become the merged list, so merging either
-    // way writes it.
+    // Both sides' writes of a list merged item by item (or of auto layout settings merged field by
+    // field) become the merged value, so merging either way writes it.
     for (bi, mi, value) in lists {
         for (changes, at) in [(&mut bc, bi), (&mut mc, mi)] {
             for i in at {
@@ -313,6 +459,8 @@ pub fn plan(base: &Document, branch: &Document, main: &Document) -> Result<Plan,
         branch: bc,
         main: mc,
         conflicts,
+        derived,
+        fields,
         branch_positions: b.replica.positions().clone(),
         main_positions: m.replica.positions().clone(),
     })
@@ -332,6 +480,42 @@ impl Plan {
         }
     }
 
+    /// Layer properties both sides changed to values both files work out for themselves (a size or
+    /// place auto layout gives, a value an instance takes from its main): not conflicts, and
+    /// merging leaves the file merged into its own value for the merged file to work out again.
+    pub fn derived(&self) -> &BTreeSet<Key> {
+        &self.derived
+    }
+
+    /// The branch's and main's values of field conflict `key` ([`Key::Field`]); `None` for other
+    /// keys.
+    pub fn field_values(&self, key: &Key) -> Option<(&Value, &Value)> {
+        let Key::Field(id, prop, name) = key else { return None };
+        let f = self.fields.get(&Key::Node(*id, *prop))?;
+        Some((f.branch.get(name)?, f.main.get(name)?))
+    }
+
+    /// The side `pick` chose for each field in conflict of every property merged field by field,
+    /// written into the value merged from the other fields: the writes that replace both sides'
+    /// own writes of those properties.
+    fn field_writes(&self, pick: &dyn Fn(&Key) -> Option<Side>) -> Vec<Change> {
+        let mut out = Vec::new();
+        for (key, f) in &self.fields {
+            let Key::Node(id, prop) = key else { continue };
+            let mut value = f.merged.clone();
+            for name in f.branch.keys() {
+                let won = if pick(&Key::Field(*id, *prop, name.clone())) == Some(Side::Branch) { &f.branch } else { &f.main };
+                match won.get(name) {
+                    Some(Value::Null) | None => value.remove(name),
+                    Some(v) => value.insert(name.clone(), v.clone()),
+                };
+            }
+            out.push(Change::Set { id: *id, prop: *prop, value: Json(Value::Object(value)) });
+        }
+        out
+    }
+
+    /// `side`'s positions (fractional keys) of the layers, for applying its changes elsewhere.
     fn positions(&self, side: Side) -> &Positions {
         match side {
             Side::Branch => &self.branch_positions,
@@ -355,7 +539,10 @@ impl Plan {
         let mut skip: BTreeSet<usize> = BTreeSet::new();
         let mut batch = Vec::new();
         for c in &self.conflicts {
-            if pick(&c.key) != Some(from) {
+            if matches!(c.key, Key::Field(..)) {
+                // Written whole below, each field from the side picked for it.
+                skip.extend(c.changes(from));
+            } else if pick(&c.key) != Some(from) {
                 skip.extend(c.changes(from));
             } else if let (Key::Layer(id), Some(by)) = (&c.key, c.deleted_by)
                 && by != from
@@ -372,7 +559,11 @@ impl Plan {
         // shortcut: images a side stopped using are kept (unused ones cost file size only); drop
         // them if files grow.
         let kept = |c: &Change| !matches!(c, Change::Remove { entry: Entry::Image(_) });
-        batch.extend(self.changes(from).iter().enumerate().filter(|(i, c)| !skip.contains(i) && kept(c)).map(|(_, c)| c.clone()));
+        // Values both files work out for themselves stay as `into` has them; normalising the merged
+        // file works them out again from what changed.
+        let own = |c: &Change| key_of(c).is_some_and(|k| self.derived.contains(&k));
+        batch.extend(self.changes(from).iter().enumerate().filter(|(i, c)| !skip.contains(i) && kept(c) && !own(c)).map(|(_, c)| c.clone()));
+        batch.extend(self.field_writes(pick));
         let mut r = Replica::from_parts(into.clone(), self.positions(from.other()).clone());
         let applied = r.apply(&batch, Mode::Strict)?;
         Ok((r.document().clone(), applied.touched))

crates/engine/src/branch_tests.rs

@@ -193,6 +193,109 @@ fn branch_commands_refuse_what_makes_no_sense() {
     assert!(s.execute("branch.merge", &json!({"id": "nope"})).is_err());
 }
 
+/// Node id `v` of a command's answer (`{"id": …}` or a bare id).
+fn idv(v: &Value) -> NodeId {
+    NodeId(v.get("id").unwrap_or(v).as_u64().unwrap())
+}
+
+/// The issue #2026 file, with a branch of it made and shown: a component `Card` (horizontal auto
+/// layout hugging its contents, padding 12, one 40×20 rectangle) and an instance of it in a
+/// vertical auto layout frame hugging its contents. Returns (session, branch id, card, instance,
+/// frame, rectangle).
+fn card_file() -> (Session, String, NodeId, NodeId, NodeId, NodeId) {
+    let mut s = Session::with_document(Document::new("Cards"));
+    let props = json!({"layout": "horizontal", "padding": 12, "sizingH": "hug", "sizingV": "hug"});
+    let frame = idv(&ok(&mut s, "frame.create", json!({"x": 0, "y": 0, "width": 100, "height": 50, "name": "Card", "props": props})));
+    let rect = idv(&ok(&mut s, "shape.rectangle", json!({"x": 0, "y": 0, "width": 40, "height": 20, "parent": frame})));
+    let card = idv(&ok(&mut s, "component.create", json!({"ids": [frame]})));
+    let props = json!({"layout": "vertical", "padding": 0, "sizingH": "hug", "sizingV": "hug"});
+    let stack = idv(&ok(&mut s, "frame.create", json!({"x": 0, "y": 200, "width": 100, "height": 100, "name": "Stack", "props": props})));
+    let inst = idv(&ok(&mut s, "instance.create", json!({"component": card, "parent": stack})));
+    let b = ok(&mut s, "branch.create", json!({"name": "padding 8"}));
+    (s, b["id"].as_str().unwrap().to_string(), card, inst, stack, rect)
+}
+
+/// Size and place of every layer of `doc` (what auto layout works out).
+fn geometry(doc: &Document) -> Vec<(NodeId, [f64; 8])> {
+    doc.nodes()
+        .map(|n| {
+            let c = n.transform.as_coeffs();
+            (n.id, [n.width, n.height, c[0], c[1], c[2], c[3], c[4], c[5]])
+        })
+        .collect()
+}
+
+/// Issue #2026: one auto layout edit on each side is one conflict (the field changed both ways),
+/// not one for every size and place auto layout works out from it; the merged file lays out
+/// from the padding picked.
+#[test]
+fn one_conflicting_auto_layout_edit_is_one_conflict() {
+    for (pick, padding) in [("branch", 8.0), ("main", 16.0)] {
+        let (mut s, id, card, inst, _, _) = card_file();
+        ok(&mut s, "node.set", json!({"id": card, "props": {"padding": 8}}));
+        ok(&mut s, "doc.switch", json!({"index": 0}));
+        ok(&mut s, "node.set", json!({"id": card, "props": {"padding": 16}}));
+        // What main looks like with the picked padding set directly.
+        let mut direct = Session::with_document(s.doc().unwrap().clone());
+        ok(&mut direct, "node.set", json!({"id": card, "props": {"padding": padding}}));
+        let review = ok(&mut s, "branch.review", json!({"id": id}));
+        let conflicts = review["conflicts"].as_array().unwrap();
+        assert_eq!(conflicts.len(), 1, "{review}");
+        let key = format!("{card}/layout.padding");
+        assert_eq!(conflicts[0]["key"], key.as_str());
+        assert_eq!(
+            (&conflicts[0]["property"], &conflicts[0]["branch"], &conflicts[0]["main"]),
+            (&json!("auto layout padding"), &json!("8, 8, 8, 8"), &json!("16, 16, 16, 16"))
+        );
+        let err = s.execute("branch.merge", &json!({"id": id})).unwrap_err().to_string();
+        assert!(err.contains(&key) && !err.contains("width"), "{err}");
+        ok(&mut s, "branch.merge", json!({"id": id, "resolutions": {&key: pick}}));
+        let doc = s.doc().unwrap();
+        for n in [card, inst] {
+            assert_eq!(doc.node(n).unwrap().layout.as_ref().unwrap().padding, [padding; 4], "{pick} wins");
+        }
+        assert_eq!(geometry(doc), geometry(direct.doc().unwrap()), "{pick} wins: laid out from the padding picked");
+    }
+}
+
+/// Auto layout merges field by field: a gap changed only on the branch is kept whichever side's
+/// padding wins, both when merging and when updating the branch from main.
+#[test]
+fn auto_layout_fields_changed_one_way_survive_a_conflict() {
+    for (cmd, pick, padding) in [("branch.merge", "main", 16.0), ("branch.merge", "branch", 8.0), ("branch.updateFromMain", "main", 16.0)] {
+        let (mut s, id, card, _, _, _) = card_file();
+        ok(&mut s, "node.set", json!({"id": card, "props": {"padding": 8, "gap": 30}}));
+        ok(&mut s, "doc.switch", json!({"index": 0}));
+        ok(&mut s, "node.set", json!({"id": card, "props": {"padding": 16, "mainAlign": "center"}}));
+        let key = format!("{card}/layout.padding");
+        let review = ok(&mut s, "branch.review", json!({"id": id}));
+        assert_eq!(review["conflicts"].as_array().unwrap().iter().map(|c| c["key"].clone()).collect::<Vec<_>>(), vec![json!(key)], "{review}");
+        ok(&mut s, cmd, json!({"id": id, "resolutions": {&key: pick}}));
+        if cmd == "branch.updateFromMain" {
+            ok(&mut s, "doc.switch", json!({"index": 1}));
+        }
+        let layout = s.doc().unwrap().node(card).unwrap().layout.clone().unwrap();
+        assert_eq!((layout.padding, layout.gap, layout.main_align), ([padding; 4], 30.0, figcraft_doc::MainAlign::Center), "{cmd}, {pick} wins");
+    }
+}
+
+/// Auto layout on one side and a hugging frame's size on both: the sizes auto layout works out
+/// on each side are no conflict, and merging leaves no stale size behind.
+#[test]
+fn sizes_auto_layout_works_out_never_conflict() {
+    let (mut s, id, card, _, stack, rect) = card_file();
+    ok(&mut s, "node.set", json!({"id": rect, "props": {"width": 60}}));
+    ok(&mut s, "doc.switch", json!({"index": 0}));
+    ok(&mut s, "node.set", json!({"id": card, "props": {"padding": 4}}));
+    let review = ok(&mut s, "branch.review", json!({"id": id}));
+    assert_eq!(review["conflicts"], json!([]), "{review}");
+    let mut direct = Session::with_document(s.doc().unwrap().clone());
+    ok(&mut direct, "node.set", json!({"id": rect, "props": {"width": 60}}));
+    ok(&mut s, "branch.merge", json!({"id": id}));
+    assert_eq!(s.doc().unwrap().node(stack).unwrap().width, 60.0 + 8.0);
+    assert_eq!(geometry(s.doc().unwrap()), geometry(direct.doc().unwrap()));
+}
+
 /// Every change a side made (that the other side didn't overwrite) shows in `doc`.
 fn shows(changes: &[Change], doc: &Document) -> Result<(), String> {
     let r = Replica::new(doc.clone());
@@ -282,16 +385,25 @@ fn random_edits_on_both_sides_merge() {
             let none = |_: &figcraft_collab::merge::Key| None;
             let (into_main, _) = p.merge(&m, Side::Branch, &none).unwrap_or_else(|e| panic!("seed {seed}: {e}"));
             let (into_branch, _) = p.merge(&b, Side::Main, &none).unwrap_or_else(|e| panic!("seed {seed}: {e}"));
+            // Values both sides work out for themselves (sizes and places auto layout gives) stay
+            // as the file merged into has them.
+            let chosen = |changes: &[Change]| -> Vec<Change> {
+                changes
+                    .iter()
+                    .filter(|c| !matches!(c, Change::Set { id, prop, .. } if p.derived().contains(&Key::Node(*id, *prop))))
+                    .cloned()
+                    .collect()
+            };
             let mut both = Replica::new(start.clone());
             both.apply(&p.main, Mode::Strict).unwrap();
-            both.apply(&p.branch, Mode::Strict).unwrap();
+            both.apply(&chosen(&p.branch), Mode::Strict).unwrap();
             let mut want = both.document().clone();
             (want.name, want.current_page) = (m.name.clone(), m.current_page);
             assert_eq!(into_main, want, "seed {seed}");
             for doc in [&into_main, &into_branch] {
                 assert!(doc.validate().is_empty(), "seed {seed}: {:?}", doc.validate());
                 for side in [&p.branch, &p.main] {
-                    shows(side, doc).unwrap_or_else(|c| panic!("seed {seed}: lost {c}"));
+                    shows(&chosen(side), doc).unwrap_or_else(|c| panic!("seed {seed}: lost {c}"));
                 }
             }
         } else {

crates/engine/src/sharing/branches.rs

@@ -611,6 +611,21 @@ fn doc_change(plan: &Plan, c: &Change) -> Option<DocChange> {
     Some(DocChange { what, change: entry_change(plan, c) })
 }
 
+/// One side's value of an auto layout field in conflict, in words: `16`, `8, 8, 8, 8`, `min`,
+/// `on`, `none`.
+fn field_text(v: &Value) -> String {
+    match v {
+        Value::Null => "none".to_string(),
+        Value::Bool(on) => if *on { "on" } else { "off" }.to_string(),
+        Value::Number(n) => n.as_f64().map_or_else(|| n.to_string(), |x| x.to_string()),
+        Value::String(s) => words(s),
+        Value::Array(items) => items.iter().map(field_text).collect::<Vec<_>>().join(", "),
+        Value::Object(_) => v.to_string(),
+    }
+}
+
+/// The review's row for conflict `c`: the layer (or file entry) and property, and what each side
+/// changed it to.
 fn conflict_row(plan: &Plan, c: &Conflict, base: &Document, head: &Document, main: &Document) -> ConflictRow {
     let layer = |id: NodeId| main.node(id).or(head.node(id)).or(base.node(id)).map_or_else(|| id.to_string(), |n| n.name.clone());
     let text = |side: Side| match c.changes(side).first().and_then(|i| plan.changes(side).get(*i)) {
@@ -627,6 +642,11 @@ fn conflict_row(plan: &Plan, c: &Conflict, base: &Document, head: &Document, mai
             let property = if *prop == Prop::Parent { "place in layers".to_string() } else { words(prop) };
             (Some(*id), layer(*id), property, b, m)
         }
+        Key::Field(id, prop, field) => {
+            let (b, m) = plan.field_values(&c.key).map_or_else(|| ("changed".into(), "changed".into()), |(b, m)| (field_text(b), field_text(m)));
+            let owner = if *prop == Prop::Layout { "auto layout".to_string() } else { words(prop) };
+            (Some(*id), layer(*id), format!("{owner} {}", field.replace('_', " ")), b, m)
+        }
         Key::Layer(id) => {
             let (b, m) = if c.deleted_by == Some(Side::Branch) { ("deleted", "edited") } else { ("edited", "deleted") };
             (Some(*id), layer(*id), "layer".to_string(), b.to_string(), m.to_string())

docs/collaboration-parity.md

@@ -1,6 +1,6 @@
 # Collaboration parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-06 · **Change:** minor (a file shared on the local network can be shared to look at only: a view-only code next to the edit code, picked in the Share popover before or while sharing)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-06 · **Change:** minor (; a file shared on the local network can be shared to look at only: a view-only code next to the edit code, picked in the Share popover before or while sharing)
 
 Figma is multiplayer first; FigCraft is local first. **Ready ~13% (estimated):** comments, version
 history and branches (review and merge) work inside one file; the real-time collaboration core landed in #103 (sync model,
@@ -18,7 +18,7 @@ cursors, selections, text carets, cursor chat and spotlights shown live ([`colla
 | Share links, permissions (view / edit), teams and projects | yes | **partial**: sharing with a join code from the Share popover (online: the file goes to the server in Preferences and the server names its edit, comment and view links with short codes; local network: the app hosts and the code carries its address, with an edit code and a view-only code, picked before or while sharing, whose holders see every change and can't make one; one field joins with a code or a link, in the popover and on the home screen, and the Join dialog then shows the join until its file is ready (Cancel), or why it failed (Try again, #1381); the browser build also joins from a link in its URL's fragment, `#join=…`, which never reaches the web host's logs, capped at 6 KiB and checked like a `figcraft://` link (#712; unit-tested, not run in a browser), and shares online and publishes to a server as the desktop app does, though not on the local network (#917; the owner token of a file it puts on an open server lasts as long as the page)); `figcraft-server` share links per file with edit, comment or view access (a viewer sees changes and presence, a "View only" badge and only the moving tools; a commenter also adds, replies to, reacts to and resolves comment threads, with a "Can comment" badge and the comment tool, #1525; the server refuses their other edits), revocable at once, tokens stored as hashes; managed from the app's Share popover (first links), the server's command line or a managing connection. On a server open to the public, whoever published a file manages it with its owner token (links, name, removal: `collab.manageFile`), which the app remembers: Home ▸ Online lists your online files (open again as owner, start and stop sharing, copy the code, rename, remove, forget), with one request per server for what became of them; anyone in a file can report it, and the operator blocks addresses. The person hosting a session, or a file's owner, removes someone from it (right-click their avatar, `collab.removePerson`): they are disconnected and their address can't join that file again while it runs. The list is per computer; a server only a team reaches can also list the files shared from it now for everyone (`team_files`): Home ▸ Online shows that team list for the server in Preferences, a row joins its file, and its links (`figcraft://join?server=…&file=…&team=1`, or the browser build's) carry no secret and stop working with the share. No accounts, teams or projects | 8–17 |
 | Comments: pins on frames and layers, threads, reactions, @mentions, resolve, unread, search and filters, links, in the presenter | yes (shared) | **done, local**: stored in the file, your name from Preferences (an AI agent attached over MCP comments as its own name, marked Agent); a behaviour suite from the documentation (pinning and following layers, threads, own edits and deletes, mentions, reactions, C and Shift+C, stepping, filters, saving, copy and paste); restoring a version keeps them. `comment.list` (CLI, MCP) gives each message its `mentions` (`{name, known, you}`, by the highlighting rule). In a live session threads sync and anyone in it can reply, react and resolve (no accounts: a name is who you are) | (shared once multiplayer lands) |
 | Version history: named versions, autosave checkpoints, view before restore, restore, duplicate | yes (cloud) | **done**, saved in the `.figcraft` file: restoring keeps the replaced design as an autosave first, a titled autosave becomes a named version, merging a branch records the file before and after. Versions are per person in a live session (a shared history needs accounts); no comparing two versions (Dev Mode compares a ready-for-dev layer with its state when marked) | — |
-| Branching and merging | yes (paid plans) | **done, also in live sessions**: branches saved in the `.figcraft` file, each opened in its own tab; Review and merge shows both sides' changes since the branch was made and the conflicts (the same property on both sides, or a layer deleted on one side and edited on the other), each resolved for the branch or main; merge as one undo step (the branch is archived, the main file's history gets a version for the merge), update from main, archive. Each branch keeps its own version history (saved, viewed and restored on the branch tab, kept when it is merged or archived; entries for its creation and updates from main); fills, strokes, effects, layout grids, export settings, guides, interactions, annotations and Dev Mode resources merge item by item. In a live session a branch stays with its author (its ids in their own client space, far above the main file's) and merging it is one edit everyone gets; peers' edits merge against the branch's own base and conflicts resolve as offline; a view link refuses merging. Left: others in the session can't see or open your branches (the server would have to keep them); text runs conflict as a whole; a branch made offline that adds layers merges only outside a session | 1–2 |
+| Branching and merging | yes (paid plans) | **done, also in live sessions**: branches saved in the `.figcraft` file, each opened in its own tab; Review and merge shows both sides' changes since the branch was made and the conflicts (the same property on both sides, or a layer deleted on one side and edited on the other), each resolved for the branch or main; merge as one undo step (the branch is archived, the main file's history gets a version for the merge), update from main, archive. Each branch keeps its own version history (saved, viewed and restored on the branch tab, kept when it is merged or archived; entries for its creation and updates from main); fills, strokes, effects, layout grids, export settings, guides, interactions, annotations and Dev Mode resources merge item by item. Auto layout settings (a frame's and a child's) merge field by field, each field changed both ways a conflict of its own (`<id>/layout.padding`), and sizes and places auto layout works out (hugging, filling, a child's place) or that an instance takes from its main are no conflict: the merged file lays them out again. In a live session a branch stays with its author (its ids in their own client space, far above the main file's) and merging it is one edit everyone gets; peers' edits merge against the branch's own base and conflicts resolve as offline; a view link refuses merging. Left: others in the session can't see or open your branches (the server would have to keep them); text runs conflict as a whole; a branch made offline that adds layers merges only outside a session | 1–2 |
 | Team / organization libraries | yes | **partial**: a file's library is published to `figcraft-server` under the file and enabled in other files by a share link (per-asset versions, background update checks, overrides kept), usage counts per component and file, swapping a library by names ([components-parity](components-parity.md), [server.md](server.md#team-libraries)). No team-wide library list, accounts or analytics over time | 4–8 |
 | Notifications, activity | yes | no | with sharing |
 
@@ -26,6 +26,7 @@ cursors, selections, text carets, cursor chat and spotlights shown live ([`colla
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-11-06 | patch | M9, #2026: one conflicting auto layout edit added a conflict for every size and place it moved (a padding changed on both sides of a file with one instance gave 10, with 15 instances 138), and a `layout` conflict took all auto layout fields together, so a gap changed only on the branch was lost if main won the padding. `merge::plan` now leaves out values both sides work out for themselves: a hugging frame's or a filling child's size, text sizing to its characters, an auto layout child's place (when both sides turn it the same way) and a value a layer in an instance takes from its main; merging keeps the file merged into's own value and normalising lays it out from the merged inputs. `layout` and `childLayout` merge field by field: a field changed on one side merges, each field changed both ways is its own conflict (`<id>/layout.padding`, shown as auto layout padding with both sides' values). Tests: `branch_tests::one_conflicting_auto_layout_edit_is_one_conflict`, `branch_tests::auto_layout_fields_changed_one_way_survive_a_conflict`, `branch_tests::sizes_auto_layout_works_out_never_conflict`; the merge fuzz test leaves worked-out values out of what each side must show |
 | 2026-11-06 | minor | M9: a file shared on the local network can be shared read-only. The session the app hosts has a second secret, so a view-only code next to the edit code (same address and port, a 44-bit secret of its own); whoever joins with it is welcomed as a viewer, sees every change and presence, gets the "View only" badge and only the moving tools, and the session refuses their edits. The Share popover offers Can edit / Can view under Local network before sharing starts (the edit code then never shows) and while sharing; `collab.share {via: "local", access: "view"}` does the same (its `link` and `url`, like its `code`, are the view-only way in), and `share` in `collab.peers` lists both codes and links. No comment code on the local network. Numbers unchanged. |
 | 2026-10-31 | patch | M9, #1665: the document in a live session's welcome goes compressed (deflate) to clients whose hello announces `packed`, about seven times smaller on the wire (a synthetic file of 4,040 layers: 397 KB to 53 KB); older clients keep getting it uncompressed, and the client reads a packed document only up to the size an uncompressed welcome could have had. |
 | 2026-10-30 | minor | M9, part of #742: a team list on `figcraft-server`. With `team_files = "edit"` (or `comment`, `view`) everyone who reaches the server sees the files shared from it now (a link of theirs has a join code: Share ▸ Start sharing) and joins them by a team list link, `figcraft://join?server=…&file=…&team=1`, which carries no secret: the server hands out the file's team link while it stays shared (`ResolveTeam`, answered like a join code), and Stop sharing revokes it with the others, disconnecting whoever joined with it. Turning the list off or changing its access refuses the old team links at once. `collab.files {refresh}` asks the server in Preferences for its list (`Admin::Team`; not the public server FigCraft ships with), and Home ▸ Online shows it below your own files: a row joins its file, its menu copies the link for the app or, with the server's `web_url`, for the browser build (`<web_url>#join=…`). A browser build served beside its server names it with `<meta name="figcraft-server">`, the page's default for sharing, codes and the team list. No accounts: the list is for a server only your team reaches. Tests: `team_tests` (the server and apps over loopback), `code_tests` (links and the browser's driver), `online_tests` (the Online section), `query_tests` (the page's server). Percentages and hours unchanged |

docs/mcp.md

@@ -1353,7 +1353,10 @@ branches). Driven with `run_command`:
   export settings, guides, prototype interactions, annotations and Dev Mode resources compare item
   by item, so changing different items of one list on each side, or adding items at its end on one
   side, merges without a conflict; other lists, such as code links, compare whole; a layer's parent
-  and position are one property, `parent`), a layer deleted on one side while the other edited it or what's inside it
+  and position are one property, `parent`; auto layout settings, `layout` and `childLayout`, compare
+  field by field, each field changed both ways its own conflict, `<layer id>/layout.padding`; sizes and
+  places auto layout works out, and values a layer in an instance takes from its main, are never
+  conflicts: the merged file works them out again), a layer deleted on one side while the other edited it or what's inside it
   (`<layer id>/layer`, with `deletedBy`), or a document-level entry or setting changed on both sides
   (`style/<id>`, `variable/<id>`, `comment/<id>`, `doc/<property>`…).
 - `branch.merge {id?, resolutions?}` merges the branch into the main file as one undo step,