G1: Fix intermediate overflow in adjoining width adjustments

Co-authored-by: Codex <noreply@openai.com>

crates/engine/src/cmd/distortcmds.rs

@@ -257,7 +257,22 @@ fn place(points: &mut Vec<(f64, f64, f64)>, mut pt: (f64, f64, f64), from_below:
 /// points at other positions either side change in proportion (by the same amount from zero).
 fn adjust_adjoining(points: &mut [(f64, f64, f64)], i: usize, old: (f64, f64, f64), new: (f64, f64, f64)) {
     let t = points[i].0;
-    let scale = |v: f64, o: f64, n: f64| if o > 1e-9 { v * n / o } else { v + n - o }.max(0.0);
+    let scale = |v: f64, o: f64, n: f64| {
+        let width = if o > 1e-9 {
+            let product = v * n;
+            if product.is_finite() {
+                // Keep the existing rounding, including small products that n/o would lose.
+                product / o
+            } else {
+                // With finite nonnegative factors, an overflowing product has both factors
+                // above one. Divide the larger first so this fallback cannot underflow.
+                (v.max(n) / o) * v.min(n)
+            }
+        } else {
+            v + n - o
+        };
+        width.max(0.0)
+    };
     let before = (0..i).rev().find(|j| (points[*j].0 - t).abs() > SAME_T);
     let after = (i + 1..points.len()).find(|j| (points[*j].0 - t).abs() > SAME_T);
     for j in before.into_iter().chain(after) {
@@ -293,8 +308,11 @@ fn width_point_set(s: &mut Session, p: &Value) -> Result<Value> {
         let st = weighted_stroke(d, id)?;
         let before = st.profile.clone();
         let half = st.width / 2.0;
-        let mut prof = st.profile.take().unwrap_or_else(uniform);
         let pt = (t, left / half, right / half);
+        if !half.is_finite() || half <= 0.0 || !pt.1.is_finite() || !pt.2.is_finite() {
+            return Err(bad(C, "width factors must be finite"));
+        }
+        let mut prof = st.profile.take().unwrap_or_else(uniform);
         pos = match point_index(p, &prof, C)? {
             Some(i) => {
                 let old = prof.points[i];
@@ -320,6 +338,11 @@ fn width_point_set(s: &mut Session, p: &Value) -> Result<Value> {
                 i
             }
         };
+        // Validate on edit_counted's copy: a failed adjoining adjustment must not change
+        // the document, its dirty state or either side of its history.
+        if prof.points.iter().any(|p| !p.1.is_finite() || !p.2.is_finite()) {
+            return Err(bad(C, "width factors must be finite"));
+        }
         st.profile = Some(prof);
         Ok(usize::from(!same_points(st.profile.as_ref(), before.as_ref())))
     })?;

crates/engine/src/tests_widthpoints.rs

@@ -230,3 +230,115 @@ fn new_width_point_adjust_adjoining_uses_sampled_widths() {
         );
     }
 }
+
+#[test]
+fn width_point_finite_extreme_adjoining_roundtrips_with_history() {
+    // Ordinary scaling, finite factors whose product overflows, and a representable
+    // normalization with a subnormal half weight. Exercise both adjoining callers.
+    for (weight, factor) in [(10.0, 1.0), (1e-200, 1e200), (f64::MIN_POSITIVE, 1.0)] {
+        for indexed in [false, true] {
+            let (mut s, id) = line_session();
+            s.execute("stroke.set", &json!({"ids": [id.0], "weight": weight})).unwrap();
+            let mut profile = vec![(0.0, factor, factor), (1.0, factor, factor)];
+            if indexed {
+                profile.insert(1, (0.5, factor, factor));
+            }
+            s.execute("stroke.widthProfile.set", &json!({"ids": [id.0], "points": profile})).unwrap();
+            s.doc_mut().unwrap().mark_saved();
+            let before = s.doc().unwrap().doc.clone();
+            let selection = s.doc().unwrap().selection.clone();
+            let undo = s.doc().unwrap().history.undo.len();
+            let index = indexed.then_some(1);
+            let side = weight * factor;
+            set(&mut s, json!({"id": id.0, "index": index, "t": 0.5, "left": side, "right": side / 4.0, "adjustAdjoining": true}));
+            let pts = points(&s, id);
+            assert_eq!(pts.len(), 3);
+            for (i, &(t, left, right)) in pts.iter().enumerate() {
+                assert_eq!(t, i as f64 / 2.0);
+                assert!(left.is_finite() && right.is_finite(), "adjoining factors must stay finite: {pts:?}");
+                assert!((left / factor - 2.0).abs() < 1e-14 && (right / factor - 0.5).abs() < 1e-14, "{pts:?}");
+            }
+            let after = s.doc().unwrap().doc.clone();
+            let st = s.doc().unwrap();
+            assert_eq!(st.selection, selection);
+            assert_eq!((st.history.undo.len(), st.history.redo.len(), st.is_dirty()), (undo + 1, 0, true));
+            assert_eq!(st.history.undo.last().unwrap().label, "Width Point");
+            let back = vectorcraft_format::load(&vectorcraft_format::save(&after, false)).unwrap();
+            assert_eq!(back, *after, "finite width edits must round-trip through the native format");
+            s.execute("edit.undo", &json!({})).unwrap();
+            let st = s.doc().unwrap();
+            assert_eq!(st.doc, before);
+            assert_eq!(st.selection, selection);
+            assert_eq!((st.history.undo.len(), st.history.redo.len(), st.is_dirty()), (undo, 1, false));
+            s.execute("edit.redo", &json!({})).unwrap();
+            let st = s.doc().unwrap();
+            assert_eq!(st.doc, after);
+            assert_eq!(st.selection, selection);
+            assert_eq!((st.history.undo.len(), st.history.redo.len(), st.is_dirty()), (undo + 1, 0, true));
+        }
+    }
+}
+
+#[test]
+fn width_point_finite_scaling_preserves_small_results() {
+    // Blindly changing v*n/o to v*(n/o) underflows n/o to zero in this case.
+    for indexed in [false, true] {
+        let (mut s, id) = line_session();
+        s.execute("stroke.set", &json!({"ids": [id.0], "weight": 2})).unwrap();
+        let mut profile = vec![(0.0, 1e200, 1e200), (1.0, 1e200, 1e200)];
+        if indexed {
+            profile.insert(1, (0.5, 1e200, 1e200));
+        }
+        s.execute("stroke.widthProfile.set", &json!({"ids": [id.0], "points": profile})).unwrap();
+        set(&mut s, json!({"id": id.0, "index": indexed.then_some(1), "t": 0.5, "left": 1e-200, "right": 1e-200, "adjustAdjoining": true}));
+        for (_, left, right) in points(&s, id) {
+            assert!(left > 0.0 && right > 0.0, "representable small widths must not become zero");
+            assert!((left / 1e-200 - 1.0).abs() < 1e-14 && (right / 1e-200 - 1.0).abs() < 1e-14);
+        }
+    }
+}
+
+#[test]
+fn width_point_nonrepresentable_widths_reject_atomically() {
+    let history = |s: &Session| {
+        let h = &s.doc().unwrap().history;
+        let entries = |es: &[HistoryEntry]| es.iter().map(|e| (e.label.clone(), e.doc.clone(), e.selection.clone(), e.bytes)).collect::<Vec<_>>();
+        (entries(&h.undo), entries(&h.redo), h.limit, h.byte_budget)
+    };
+    for (case, weight, ends, middle, left) in [
+        ("normalized overflow", 1e-310, 1.0, 1.0, 1.0),
+        ("half weight rounds to zero", f64::from_bits(1), 1.0, 1.0, 0.0),
+        ("adjoining proportional overflow", 2.0, 1e308, 1.0, 4.0),
+        ("adjoining additive overflow", 1e-308, 1e308, 0.0, 0.5),
+    ] {
+        for indexed in [false, true] {
+            let (mut s, id) = line_session();
+            s.execute("stroke.set", &json!({"ids": [id.0], "weight": weight})).unwrap();
+            // The first neighbour can change before the second overflows; neither may commit.
+            s.execute("stroke.widthProfile.set", &json!({"ids": [id.0], "points": [[0, 1, 1], [0.5, middle, 1], [1, ends, 1]]})).unwrap();
+            s.execute("shape.rectangle", &json!({"x": 10, "y": 10, "width": 20, "height": 20})).unwrap();
+            let redo_doc = s.doc().unwrap().doc.clone();
+            s.execute("edit.undo", &json!({})).unwrap();
+            s.doc_mut().unwrap().mark_saved();
+            let before = s.doc().unwrap().doc.clone();
+            let selection = s.doc().unwrap().selection.clone();
+            let revision = s.doc().unwrap().revision;
+            let before_history = history(&s);
+            assert_eq!(s.doc().unwrap().history.redo.len(), 1);
+            let result = s.execute(
+                "stroke.widthPoint.set",
+                &json!({"id": id.0, "index": indexed.then_some(1), "t": 0.5, "left": left, "right": 0, "adjustAdjoining": true}),
+            );
+            assert!(result.is_err(), "{case}, indexed={indexed}: accepted nonrepresentable width factors");
+            assert_eq!(s.doc().unwrap().doc, before, "{case}");
+            assert_eq!(s.doc().unwrap().selection, selection, "{case}");
+            assert_eq!(s.doc().unwrap().revision, revision, "{case}");
+            assert_eq!(history(&s), before_history, "{case}");
+            assert!(!s.doc().unwrap().is_dirty(), "{case}");
+            s.execute("edit.redo", &json!({})).unwrap();
+            assert_eq!(s.doc().unwrap().doc, redo_doc, "{case}: pre-existing redo remains usable");
+            s.execute("edit.undo", &json!({})).unwrap();
+            assert_eq!(s.doc().unwrap().doc, before, "{case}");
+        }
+    }
+}

docs/ui-parity.md

@@ -1,6 +1,6 @@
 # UI and interaction parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-14 · **Change:** minor (Image Trace adjustment discovery; later 2026-10-14 merges: macOS save sheet Format menu back to missing, #1855, #866 reopened; anchor X/Y/W/H in the Transform panel, Properties and Control bar, #1824; Snap to Grid over Snap to Pixel, #1816; toolbar labels, columns and the All Tools drawer, #1751; Actions panel selection, #1629 in part; scores unchanged; 2026-10-14 merges: anchor Align and Distribute, #1636; Delete on closed paths and whole objects, #1674; selection inside isolation, #1666; Escape in a Direct Selection drag and while typing, #1743, #1686; Pen clicks under 3 px, #1663; [ and ] on more tools, #1661 in part; fields commit on click away, #1787; command search keys, #1757; a guide's position in the Transform panel is a convenience with no parity claim, #1659; scores unchanged; intersect Smart Guides for drawn points and dragged anchors, #1602 in part; a ruler guide's position in the Transform panel, #1597 in part; Symbol Options before New Symbol, #1560; tool flyout widths, #1616; Pathfinder Trim, Merge and Crop strokes, #1570; scores unchanged; G1/M11: Artboard deletion and history selection normalization; history regressions and full workspace CI pass; scores and hours unchanged; Width Point Edit: Shift-double-click enables adjoining adjustment; plain double-click keeps it off; scores and hours unchanged; per-corner radius fields with a link toggle, split from #1594; Join merges anchors lying on one another, #1533; correction: Average and Join with a corner or smooth choice is missing, not done; guide objects take the guide colour and style and Lock Guides, #1534; Keyboard Shortcuts lists commands outside the menus, #1539; round corners next to curves and the Smooth tool's reach, #1512; Make Compound Path on a group, #1537; dialog slider rails, #1483; template layers stay in Preview in Outline view, #1486; Direct Selection takes the selected object's anchor where anchors coincide, #1508; Tabs panel stop drags, #1458; Split Into Grid dialog, #1462; Transform Objects and Reflect's angle, #1448 and #1460; Pathfinder panel on a group, #1450; value fields: readable selection, #1465 in part, and a focused field follows its value, #1457; scores unchanged; Transform dialogs have a live Preview and step with the arrow keys, #1412; transform tools, dialogs and Move act on direct-selected anchors, #1408; the bounding box hides during a corner drag, #1229; scores unchanged; dialogs focus their first field on every open, #1367, and a first field that starts greyed out once it is enabled, #1395; scores unchanged; Rectangular Grid and Polar Grid click dialogs take the skew, frame, compound path and Fill Grid options, #1377 in part, score unchanged; Live Corners: a Direct Selection click on a widget selects its corner, #1239; custom ruler origin, #1212; Artboard tool clicks fit the topmost editable object in one undo step (#1227); scores unchanged; Pathfinder single-result source names and SVG IDs retained, #1293; DXF control-point SPLINE closure read, #1299 follow-up; Document Setup: Edit Artboards closes the modal after applying valid settings; pointer-click regressions; scores and hours unchanged; Artboards: Escape exits editing; an active drag cancels first; shortcut-routing regression; scores and hours unchanged; Simplify preview/counts and valid rewritten-path selection (#1272); parity remains partial; Texture-effect drag redraws optimized (#1257); idle Windows interaction still unverified; scores unchanged; Curvature point display improved (#1236, in part); scores unchanged; Direct Selection: no-op anchor Align preserves Undo, Redo and saved state (#1180 follow-up); Eyedropper cursor distinguished from precise crosshair (#1269); scores unchanged; Eyedropper can read visible locked and outside-isolation sources (#1251); scores unchanged; Direct Selection: independent segment picks and Delete (#1278); scores unchanged; Adding paint to an unpainted zero-width stroke restores the 1 pt default (#1253); scores unchanged; macOS save sheets offer a Format menu, #866; Attributes fill-rule controls edit the compound when a member is selected, #1197; a marquee needs to touch a path, not just lie inside its fill, #1103; earlier: Live Corners round corners between curved sides, #1144) · **Target:** Adobe Illustrator 2026 (30.x)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-14 · **Change:** minor (Width-point finite-arithmetic follow-up validated; scores and hours unchanged; Image Trace adjustment discovery; later 2026-10-14 merges: macOS save sheet Format menu back to missing, #1855, #866 reopened; anchor X/Y/W/H in the Transform panel, Properties and Control bar, #1824; Snap to Grid over Snap to Pixel, #1816; toolbar labels, columns and the All Tools drawer, #1751; Actions panel selection, #1629 in part; scores unchanged; 2026-10-14 merges: anchor Align and Distribute, #1636; Delete on closed paths and whole objects, #1674; selection inside isolation, #1666; Escape in a Direct Selection drag and while typing, #1743, #1686; Pen clicks under 3 px, #1663; [ and ] on more tools, #1661 in part; fields commit on click away, #1787; command search keys, #1757; a guide's position in the Transform panel is a convenience with no parity claim, #1659; scores unchanged; intersect Smart Guides for drawn points and dragged anchors, #1602 in part; a ruler guide's position in the Transform panel, #1597 in part; Symbol Options before New Symbol, #1560; tool flyout widths, #1616; Pathfinder Trim, Merge and Crop strokes, #1570; scores unchanged; G1/M11: Artboard deletion and history selection normalization; history regressions and full workspace CI pass; scores and hours unchanged; Width Point Edit: Shift-double-click enables adjoining adjustment; plain double-click keeps it off; scores and hours unchanged; per-corner radius fields with a link toggle, split from #1594; Join merges anchors lying on one another, #1533; correction: Average and Join with a corner or smooth choice is missing, not done; guide objects take the guide colour and style and Lock Guides, #1534; Keyboard Shortcuts lists commands outside the menus, #1539; round corners next to curves and the Smooth tool's reach, #1512; Make Compound Path on a group, #1537; dialog slider rails, #1483; template layers stay in Preview in Outline view, #1486; Direct Selection takes the selected object's anchor where anchors coincide, #1508; Tabs panel stop drags, #1458; Split Into Grid dialog, #1462; Transform Objects and Reflect's angle, #1448 and #1460; Pathfinder panel on a group, #1450; value fields: readable selection, #1465 in part, and a focused field follows its value, #1457; scores unchanged; Transform dialogs have a live Preview and step with the arrow keys, #1412; transform tools, dialogs and Move act on direct-selected anchors, #1408; the bounding box hides during a corner drag, #1229; scores unchanged; dialogs focus their first field on every open, #1367, and a first field that starts greyed out once it is enabled, #1395; scores unchanged; Rectangular Grid and Polar Grid click dialogs take the skew, frame, compound path and Fill Grid options, #1377 in part, score unchanged; Live Corners: a Direct Selection click on a widget selects its corner, #1239; custom ruler origin, #1212; Artboard tool clicks fit the topmost editable object in one undo step (#1227); scores unchanged; Pathfinder single-result source names and SVG IDs retained, #1293; DXF control-point SPLINE closure read, #1299 follow-up; Document Setup: Edit Artboards closes the modal after applying valid settings; pointer-click regressions; scores and hours unchanged; Artboards: Escape exits editing; an active drag cancels first; shortcut-routing regression; scores and hours unchanged; Simplify preview/counts and valid rewritten-path selection (#1272); parity remains partial; Texture-effect drag redraws optimized (#1257); idle Windows interaction still unverified; scores unchanged; Curvature point display improved (#1236, in part); scores unchanged; Direct Selection: no-op anchor Align preserves Undo, Redo and saved state (#1180 follow-up); Eyedropper cursor distinguished from precise crosshair (#1269); scores unchanged; Eyedropper can read visible locked and outside-isolation sources (#1251); scores unchanged; Direct Selection: independent segment picks and Delete (#1278); scores unchanged; Adding paint to an unpainted zero-width stroke restores the 1 pt default (#1253); scores unchanged; macOS save sheets offer a Format menu, #866; Attributes fill-rule controls edit the compound when a member is selected, #1197; a marquee needs to touch a path, not just lie inside its fill, #1103; earlier: Live Corners round corners between curved sides, #1144) · **Target:** Adobe Illustrator 2026 (30.x)
 
 How VectorCraft's tools, handles, snapping and panels behave next to Illustrator's. A vector illustrator's
 trust is in the details: where a handle lands, what Shift and Alt do mid-drag, what a smart guide snaps to,
@@ -151,7 +151,7 @@ tools, never checked side by side) isn't captured row by row.
 | Cmd/Ctrl: last-used selection tool; Cmd+Alt: Group Selection inside Direct Selection | partial | |
 | Eyedropper reads visible sources while their layer/object is locked or outside isolation | done | Ordinary/Shift/Shift+Alt and gradient-stop reads preserve the source and selection; Alt reverse remains editable-only; hidden art stays excluded (`eyedropper_sources.rs`, #1251) |
 | Add a visible stroke after drawing with inherited None/zero-width paint | done | Paint and Swap Fill/Stroke restore the existing 1 pt default; positive widths and painted zero widths stay as set; Undo/Redo and targeted appearance items tested (`stroke_visibility.rs`, #1253) |
-| Double-click a stroked segment to create a width point in Width Point Edit | done | Command and pointer regressions cover opening, sampled widths, adjoining adjustment on/off through checkbox/OK, compound paths, Cancel/Delete and Undo/Redo; dialog layout reviewed. [Validation evidence](target-app-parity.md#evidence-what-ships-today-by-area) |
+| Double-click a stroked segment to create a width point in Width Point Edit | done | Finite-arithmetic follow-up: engine regressions and full CI passed; [Validation evidence](target-app-parity.md#evidence-what-ships-today-by-area). Command and pointer regressions cover opening, sampled widths, adjoining adjustment on/off through checkbox/OK, compound paths, Cancel/Delete and Undo/Redo; dialog layout reviewed. [Validation evidence](target-app-parity.md#evidence-what-ships-today-by-area) |
 | Shift-double-click a width point enables adjoining adjustment in Width Point Edit | done | Tool dispatch, plain double-click control, neighboring widths, Undo/Redo and Cancel in `dialogs/width_point.rs` |
 | Alt-drag duplicates (objects, artboards with their art) | done | |
 | Document Setup → Edit Artboards applies valid settings, closes the dialog and activates the Artboard tool | done | Pointer-click tests cover successful handoff, invalid settings, OK, Cancel and Undo in `dialogs/document_setup.rs`. |
@@ -226,6 +226,7 @@ re-measure of the panels added since. Slider rails show on Medium Dark (#1808, #
 |---|---|---|
 | 2026-10-14 | minor | Quick Image Trace presets reveal the adjustment panel with Advanced open; Properties reopens it. Sliders keep their preset row until release so the re-trace is committed. UI regressions added; scores and remaining estimates unchanged. |
 | 2026-10-14 | minor | The macOS save sheet's Format menu goes back to missing: #1855 withdrew it to restore saving (#866 reopened). Rows added for the X/Y/W/H of direct-selected anchors (#1839, fixes #1824), the toolbar and All Tools drawer (#1751) and the Actions panel selection (#1853, part of #1629); the snapping row notes Snap to Grid over Snap to Pixel (#1840). Scores unchanged (estimated) |
+| 2026-10-14 | minor | Width-point finite-arithmetic follow-up: atomicity, history and native round-trip regressions and current full CI passed; scores and hours unchanged. |
 | 2026-10-14 | minor | Align and Distribute act on the anchor points selected with Direct Selection: the points of one path align to each other, not to the artboard, and Distribute spaces them (#1641, fixes #1636; aligning to a key anchor is still missing); Delete removes every selected anchor of a closed path (it used to remove the wrong ones), removes objects selected whole along with the selected anchors of others, and keeps the remainder selected so a second Delete removes it (#1674); In isolation mode Direct Selection and Group Selection pick only inside the isolated object (#1666); Escape cancels a Direct Selection drag (#1803, #1743); Escape while typing ends the edit, keeps the type selected and switches to the Selection tool (#1802, #1686, #1656); A filled Pencil path keeps a stroke of None (#1804, part of #1679); With the Pen, a press that moves under 3 screen pixels is a click (a corner without handles), and a Precise Cursors command toggles the existing preference and can take a shortcut (#1663); The [ and ] keys reach the Blob Brush, the Eraser and the Symbolism tools in the app (#1734, part of #1661); In the Pathfinder panel a group selected alone counts its nested shapes, so an expanded stroked object keeps the Shape Modes enabled (#1642, #1635); Object › Expand turns radial, grid and mirror repeats into groups of their instances (#1765, #1756); Select › Same matches type on its characters' fill and stroke (#1746, #1737); Fields commit what was typed when you click away or move to another field, as Enter does; Escape still discards it (#1787); Up and Down move through the command search results and Enter runs the highlighted one (#1798, #1757); Slider rails show on Medium Dark (#1808, #1662); On Windows the custom title bar's window stays truly borderless, so the pointer lines up with what is drawn on systems where the hidden caption offset it (#1791, #1758; awaiting the reporter's confirmation); Tool cursors are painted into the window on Wayland (#1652; not run on Linux, #1645 stays open until confirmed); the guide-position row (#1659) is now "not scored": the documentation found doesn't establish it, and it is kept as a convenience pending the owner's decision; scores unchanged |
 | 2026-10-13 | minor | Pathfinder's Trim, Merge and Crop remove the objects' strokes, and Merge joins same-fill objects whatever their strokes were, as the public Pathfinder page describes (#1572, fixes #1570); Offset Path with an inset larger than the shapes says the offset leaves nothing, instead of asking to select paths (#1591, fixes #1590); The Symbols panel's New Symbol opens Symbol Options to name the symbol first, and Alt-click skips it (#1566, fixes #1560); Tool flyouts are as wide as their longest translated name and shortcut need, so names no longer run into shortcuts in Spanish and other languages (#1650, fixes #1616); Smart Guides: a point drawn with the Pen or a shape tool, and an anchor dragged with Direct Selection, snaps to where paths and ruler guides cross, labelled "intersect" (#1658, part of #1602; a moved selection's own anchors don't); The Transform panel shows a selected ruler guide's X or Y, and typing a value moves it (#1659, part of #1597). This is not established by the documentation we could find: the public help pages on guides, rulers and the Transform, Control and Properties panels (read again on 2026-10-14) describe selecting and dragging unlocked guides and the panels' X and Y for a selection, not a guide's position in a panel, and the one public statement of it is a user's [community answer](https://community.adobe.com/questions-652/adding-a-new-custom-guide-785586), which is not documentation. It is kept as a convenience pending the owner's decision, with no parity claim and nothing counted towards a score; Select Behind (Ctrl/Cmd-click) tests each object once, so a deep stack of overlapping objects no longer slows it; same objects in the same order (#1571); Commands that take `ids` run on the objects given with nothing selected, over MCP, the control channel and the CLI too (#1577, fixes #1575); scores unchanged (estimated) |
 | 2026-10-13 | minor | G1/M11: Artboard panel deletion, protected deletion keys and navigator/tool synchronization before and after deletion; history normalization preserves valid multiselection; history regressions and full workspace CI pass; scores and hours unchanged |