Correctly find parent for single-child sections

More like pages with associated files, really

hooks/nav.py

@@ -23,6 +23,15 @@ def children(page):
 
     return page_children
 
+def get_parent_page(page):
+    if is_list_page(page) and len(page.parent.children) == 1:
+        parent_section = page.parent.parent
+        if parent_section:
+            return parent_section.children[0]
+
+    return page.parent
+
+
 @jinja2.pass_context
 def get_page(context, slug):
     nav = context["nav"]
@@ -45,3 +54,4 @@ def on_env(env, config, files):
     env.filters["children"] = children
     env.globals["get_page"] = get_page
     env.globals["get_page_url"] = get_page_url
+    env.globals["get_parent_page"] = get_parent_page

theme/main.html

@@ -3,6 +3,7 @@
 Nav: {{ nav }}
 
 Parent: {{ page.parent }}
+Custom parent: {{ get_parent_page(page) }}
 Section: {{ page.is_section }}
 
 Is lits page: {{ page|is_list_page }}