fix: avoid panic in layout when a section has no page definition

src/render/layout.rs

@@ -80,10 +80,10 @@ impl<'a> LayoutEngine<'a> {
         let mut pages = Vec::new();
 
         // Get page definition
-        let page_def = section
-            .page_def
-            .as_ref()
-            .expect("Section must have page definition");
+        let page_def = match section.page_def.as_ref() {
+            Some(page_def) => page_def,
+            None => return pages,
+        };
 
         let mut current_page = RenderedPage {
             width: page_def.width,

tests/layout_missing_page_def_test.rs

@@ -0,0 +1,22 @@
+use hwpers::render::layout::LayoutEngine;
+use hwpers::HwpReader;
+use std::path::PathBuf;
+
+/// A section without a PageDef record must not panic during layout.
+/// `styled_document.hwp` (shipped in the repo) parses into a section whose
+/// `page_def` is `None`, which previously triggered a panic in `layout_section`.
+#[test]
+fn test_layout_section_without_page_def_does_not_panic() {
+    let path = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("styled_document.hwp");
+    let bytes = std::fs::read(&path).expect("failed to read styled_document.hwp");
+    let doc = HwpReader::from_bytes(&bytes).expect("failed to parse styled_document.hwp");
+
+    assert!(
+        doc.sections().any(|s| s.page_def.is_none()),
+        "expected at least one section without a page definition"
+    );
+
+    let engine = LayoutEngine::new(&doc);
+    let result = engine.calculate_layout();
+    assert!(result.pages.is_empty());
+}