M2: a text keeps a max height or a number of max lines, not both (#1832)

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>

crates/engine/src/cmd/props.rs

@@ -759,6 +759,14 @@ fn apply_sizing(cmd: &str, doc: &mut Document, id: NodeId, k: &str, v: &Value) -
                 other => Some(f64_of(other).ok_or_else(|| bad(cmd, format!("`{k}` must be a number or null")))?.clamp(0.0, 1e7)),
             };
             set_limit(&mut doc.get_mut(id)?.child_layout, k, val);
+            // A text has a max height or a number of max lines, not both: a max height sets the
+            // lines back to Auto (Guide to auto layout).
+            if k == "maxHeight"
+                && val.is_some()
+                && let Some(t) = doc.get_mut(id)?.kind.text_mut()
+            {
+                t.max_lines = 0;
+            }
         }
         "columnTracks" | "gridColumnTracks" | "rowTracks" | "gridRowTracks" => {
             let a = v.as_array().ok_or_else(|| bad(cmd, format!("`{k}` must be an array of tracks")))?;
@@ -900,7 +908,16 @@ fn apply_text(cmd: &str, doc: &mut Document, id: NodeId, props: &Map<String, Val
             *if k == "hangingList" { &mut t.hanging_list } else { &mut t.hanging_punctuation } = on;
         }
         "leadingTrim" => text_mut(cmd, doc.get_mut(id)?)?.leading_trim = enum_of(v).ok_or_else(|| bad(cmd, "leadingTrim: none|capHeight"))?,
-        "maxLines" => text_mut(cmd, doc.get_mut(id)?)?.max_lines = f64_of(v).unwrap_or(0.0).clamp(0.0, 10_000.0) as u32,
+        "maxLines" => {
+            let lines = f64_of(v).unwrap_or(0.0).clamp(0.0, 10_000.0) as u32;
+            let n = doc.get_mut(id)?;
+            text_mut(cmd, n)?.max_lines = lines;
+            // A text has a max height or a number of max lines, not both: a number of lines takes
+            // the max height away (Guide to auto layout).
+            if lines > 0 {
+                n.child_layout.max_h = None;
+            }
+        }
         "features" | "textFeatures" | "fontFeatures" | "openTypeFeatures" => {
             let f = features_of(cmd, v)?;
             let t = text_mut(cmd, doc.get_mut(id)?)?;

crates/engine/src/cmd/text.rs

@@ -323,12 +323,30 @@ pub fn specs() -> Vec<CommandSpec> {
             true,
             |s, p| {
                 let v = finite(req_num("text.maxLines", p, "lines")?).clamp(0.0, 10_000.0) as u32;
-                para(s, p, |t| {
+                let r = para(s, p, |t| {
                     t.max_lines = v;
                     if v > 0 && t.auto_resize != TextAutoResize::Height {
                         t.auto_resize = TextAutoResize::Truncate;
                     }
-                })
+                })?;
+                // A text has a max height or a number of max lines, not both (Guide to auto layout).
+                if v > 0 {
+                    let ids = match textedit::selected_range(s) {
+                        Some((id, _, _)) => vec![id],
+                        None => targets(s, p),
+                    };
+                    let doc = s.doc_mut()?;
+                    for i in ids {
+                        for d in doc.subtree(i) {
+                            if let Some(n) = doc.node_mut(d)
+                                && n.kind.text().is_some()
+                            {
+                                n.child_layout.max_h = None;
+                            }
+                        }
+                    }
+                }
+                Ok(r)
             }
         ),
         spec!(

crates/engine/src/text_behaviour_tests.rs

@@ -551,6 +551,36 @@ fn css_font_family_escapes_backslash_and_newline() {
     assert!(css.contains(r#"font-family: "Foo\"\3C /style>";"#), "{css}");
 }
 
+/// "Text layers cannot have both a max height and a set number of max lines. Adding a max height
+/// will set max lines to Auto. Setting max lines to a number will remove the layer's max height
+/// setting." (Guide to auto layout)
+#[test]
+fn a_text_has_a_max_height_or_max_lines_not_both() {
+    let mut s = Session::new();
+    let f = id(s.execute("frame.create", &json!({"x": 0, "y": 0, "width": 300, "height": 100})).unwrap());
+    s.execute("node.set", &json!({"id": f, "props": {"layout": "vertical"}})).unwrap();
+    let t = id(s.execute("text.create", &json!({"text": "Hello there world", "x": 0, "y": 0, "parent": f, "width": 60})).unwrap());
+    let state = |s: &Session| {
+        let n = s.doc().unwrap().node(t).unwrap().clone();
+        (n.kind.text().unwrap().max_lines, n.child_layout.max_h)
+    };
+    s.execute("node.set", &json!({"id": t, "props": {"maxLines": 2}})).unwrap();
+    assert_eq!(state(&s), (2, None));
+    s.execute("node.set", &json!({"id": t, "props": {"maxHeight": 40}})).unwrap();
+    assert_eq!(state(&s), (0, Some(40.0)), "a max height sets max lines to Auto");
+    s.execute("node.set", &json!({"id": t, "props": {"maxLines": 3}})).unwrap();
+    assert_eq!(state(&s), (3, None), "max lines take the max height away");
+    s.execute("node.set", &json!({"id": t, "props": {"maxHeight": 50}})).unwrap();
+    s.execute("text.maxLines", &json!({"ids": [t], "lines": 1})).unwrap();
+    assert_eq!(state(&s), (1, None), "the Max lines command too");
+    // Auto (0) leaves a max height alone, and a frame's max height has no lines to clear.
+    s.execute("node.set", &json!({"id": t, "props": {"maxHeight": 50}})).unwrap();
+    s.execute("node.set", &json!({"id": t, "props": {"maxLines": 0}})).unwrap();
+    assert_eq!(state(&s), (0, Some(50.0)));
+    s.execute("node.set", &json!({"id": f, "props": {"maxHeight": 80}})).unwrap();
+    assert_eq!(s.doc().unwrap().node(f).unwrap().child_layout.max_h, Some(80.0));
+}
+
 /// "Links are styled with an underline by default. Use the keyboard shortcut to remove the
 /// underline: Mac: Command U, Windows: Control U" (Add links to text).
 #[test]

docs/auto-layout-parity.md

@@ -1,6 +1,6 @@
 # Auto layout and constraints parity
 
-> **Last reviewed:** 2026-10-11 · **Last updated:** 2026-11-01 · **Change:** minor (Remove all auto layout, as the help center's More layout options has it: `layout.removeAll` takes the auto layout off a frame and every frame nested in it in one undo step; grid auto-placement looks for free cells a 64-bit word at a time and skips what blocks it, with the same placements (#1083); Layout sidebar: Add auto layout (+) is available for groups and converts a single group to a frame in place, with mask order, flow-only inference and Fill sizing preserved; adding auto layout to an empty frame keeps its size (#369); `node.set` applies auto layout keys only to frames, with warnings (#603); core editor leftovers: auto gap handles, wrapped-line alignment; behaviour suite written from the public documentation, every rule's status; fixes and the missing settings it found) · **Target:** Figma Design (desktop app 126.10.7)
+> **Last reviewed:** 2026-10-11 · **Last updated:** 2026-11-01 · **Change:** minor (a text keeps a max height or a number of max lines, not both, as the Guide to auto layout says: a max height sets max lines to Auto and max lines remove the max height; Remove all auto layout, as the help center's More layout options has it: `layout.removeAll` takes the auto layout off a frame and every frame nested in it in one undo step; grid auto-placement looks for free cells a 64-bit word at a time and skips what blocks it, with the same placements (#1083); Layout sidebar: Add auto layout (+) is available for groups and converts a single group to a frame in place, with mask order, flow-only inference and Fill sizing preserved; adding auto layout to an empty frame keeps its size (#369); `node.set` applies auto layout keys only to frames, with warnings (#603); core editor leftovers: auto gap handles, wrapped-line alignment; behaviour suite written from the public documentation, every rule's status; fixes and the missing settings it found) · **Target:** Figma Design (desktop app 126.10.7)
 
 Auto layout is the most used layout feature in Figma and the one where small differences (a
 hugging frame one pixel off, text wrapping at another width) break real files. **Breadth ~98%,
@@ -42,6 +42,7 @@ Status: **pass** (a case in the suite holds), **fixed** (the suite found a diver
 | Hug only on auto layout frames (and text); Fill only in an auto layout flow, never on a top-level frame | pass | `al_behaviour_tests::hug_and_fill_only_where_they_apply` |
 | Min/max width and height bound Hug, Fill and Fixed sizes, on frames and children | pass | `sizing_rules`; a fill child at its max leaves the rest to the other fill children (silent on redistribution: CSS flexbox) |
 | A hugging text wider than its max width wraps at the max | pass | `sizing_rules` |
+| A text has a max height or a number of max lines, not both: a max height sets max lines to Auto, a number of max lines removes the max height | **fixed** | both coexisted; `node.set {maxHeight}` and `{maxLines}` and `text.maxLines` keep one of the two (a frame's max height is untouched); `text_behaviour_tests::a_text_has_a_max_height_or_max_lines_not_both` |
 | Remove all auto layout: a frame and all of its nested objects lose their auto layout at once (More layout options) | **added** | `layout.removeAll {ids?}`, one undo step, in the canvas context menu beside Add auto layout; instances and the layers inside them keep theirs; `al_nesting_tests::remove_all_auto_layout_strips_the_frame_and_every_frame_nested_in_it` |
 | Text filling a width wraps and its hugging frame grows with it | pass | `sizing_rules` |
 | A hugging frame follows a child that grows, through nested levels, in one edit and one undo step | pass | `al_behaviour_tests::a_hugging_frame_follows_its_children_through_nested_levels` |
@@ -96,6 +97,7 @@ Status: **pass** (a case in the suite holds), **fixed** (the suite found a diver
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-11-01 | patch | M2: a text layer keeps a max height or a number of max lines, not both ("Text layers cannot have both a max height and a set number of max lines", Guide to auto layout): `node.set {maxHeight}` on a text sets its max lines to Auto, and `node.set {maxLines}` or `text.maxLines` with a number removes its max height. Found by a documentation audit of this page. Test: `text_behaviour_tests::a_text_has_a_max_height_or_max_lines_not_both`. Numbers unchanged |
 | 2026-11-01 | minor | M2: Remove all auto layout ("To remove auto layout from a frame and all of its nested objects at once, right-click on the frame and go to More layout options > Remove all auto layout", Toggle on auto layout in designs): `layout.removeAll {ids?}` strips the frames and every frame nested in them in one undo step, leaving instances and their layers alone; in the canvas context menu beside Add auto layout and in the Actions palette. Found by a documentation audit of this page. Test: `al_nesting_tests::remove_all_auto_layout_strips_the_frame_and_every_frame_nested_in_it`. Numbers unchanged |
 | 2026-10-30 | minor | M8, #1083: grid placement finds free cells on a bitmap, a word at a time, with the same placements; crafted grids of wide children no longer stall a layout pass. Numbers unchanged. |
 | 2026-10-29 | minor | M2 review fixes: conversion preserves mask runs and Fill sizing per axis; layout inference uses visible, non-absolute flow children; the sidebar hides Add for mixed selections containing existing auto layout. Regression coverage includes rendered mask pixels, visible-child positions, parent layout stability and the sidebar accessibility tree. Numbers unchanged |