Fix validation of heading 1 in a page, now only validate pages that a…

…re actually in the navigation

mkdocs_print_site_plugin/plugin.py

@@ -9,7 +9,7 @@
 from mkdocs.utils import write_file, copy_file, get_relative_url, warning_filter
 
 from mkdocs_print_site_plugin.renderer import Renderer
-from mkdocs_print_site_plugin.utils import get_theme_name
+from mkdocs_print_site_plugin.utils import flatten_nav, get_theme_name
 
 logger = logging.getLogger("mkdocs.plugins")
 logger.addFilter(warning_filter)
@@ -147,6 +147,7 @@ def on_nav(self, nav, config, files, **kwargs):
 
         # Save the (order of) pages and sections in the navigation before adding the print page
         self.renderer.items = nav.items
+        self.all_pages_in_nav = flatten_nav(nav.items)
 
         # Optionally add the print page to the site navigation
         if self.config.get("add_to_navigation"):
@@ -172,12 +173,13 @@ def on_page_content(self, html, page, config, files, **kwargs):
         # We need to validate that the first heading on each page is a h1
         # This is required for the print page table of contents and enumeration logic
         if self.config.get("add_table_of_contents") or self.config.get("enumerate_headings"):
-            match = re.search(r"\<h[0-6]", html)
-            if match:
-                if not match.group() == "<h1":
-                    msg = f"The page {page.title} ({page.file.src_path}) does not start with a level 1 heading."
-                    msg += "This is required for print page Table of Contents and/or enumeration of headings."
-                    raise AssertionError(msg)
+            if page in self.all_pages_in_nav:
+                match = re.search(r"\<h[0-6]", html)
+                if match:
+                    if not match.group() == "<h1":
+                        msg = f"The page {page.title} ({page.file.src_path}) does not start with a level 1 heading."
+                        msg += "This is required for print page Table of Contents and/or enumeration of headings."
+                        raise AssertionError(msg)
 
         # Link to the PDF version of the entire site on a page.
         if self.config.get("path_to_pdf") != "":

mkdocs_print_site_plugin/utils.py

@@ -24,3 +24,17 @@ def get_theme_name(config) -> str:
         return "mkdocs"
     else:
         return name
+
+
+def flatten_nav(items):
+    """
+    Create a flat list of pages from a nested navigation.
+    """
+    pages = []
+
+    for item in items:
+        if item.is_page:
+            pages.append(item)
+        if item.is_section:
+            pages.append(flatten_nav(item.children))
+    return pages