#1378: max lines only while truncation is ENDING, with a REST test for auto height with truncation off

crates/format/src/rest/tests.rs

@@ -365,6 +365,17 @@ fn text_styles_and_runs() {
     assert!(!named(&doc, "NoFills").fills.is_empty(), "text keeps its default fill");
 }
 
+#[test]
+fn max_lines_apply_only_while_truncating() {
+    let (doc, _) = one(json!([
+        {"id": "1", "name": "Auto", "type": "TEXT", "relativeTransform": at(0.0, 0.0), "size": {"x": 100, "y": 20}, "characters": "a",
+         "style": {"textAutoResize": "HEIGHT", "textTruncation": "DISABLED", "maxLines": 2}}
+    ]));
+    let NodeKind::Text(td) = &named(&doc, "Auto").kind else { panic!() };
+    assert_eq!((td.auto_resize, td.max_lines), (TextAutoResize::Height, 0));
+    assert!(!td.truncates());
+}
+
 #[test]
 fn auto_layout_constraints_and_grids() {
     let (doc, _) = one(json!([

crates/format/src/rest/text.rs

@@ -69,9 +69,11 @@ fn paragraph(s: &Value, td: &mut TextData) {
         // Missing means a fixed box.
         _ => TextAutoResize::None,
     };
-    td.max_lines = num(s, "maxLines").filter(|n| *n >= 1.0).map_or(0, |n| n.min(10_000.0) as u32);
+    // A line limit applies only while truncation is on; a leftover `maxLines` is ignored.
+    let ending = text(s, "textTruncation") == Some("ENDING");
+    td.max_lines = num(s, "maxLines").filter(|n| ending && *n >= 1.0).map_or(0, |n| n.min(10_000.0) as u32);
     // Auto height with a line limit keeps hugging its lines up to the limit.
-    if text(s, "textTruncation") == Some("ENDING") && !td.truncates() {
+    if ending && !td.truncates() {
         td.auto_resize = TextAutoResize::Truncate;
     }
     td.paragraph_spacing = len(s, "paragraphSpacing").unwrap_or(0.0);