From 0b98f96ae0a8f56d9a530365c9b3d191e597886f Mon Sep 17 00:00:00 2001
From: Alexander Madyankin <alexander@madyankin.name>
Date: Fri, 13 Jun 2025 21:48:35 +0200
Subject: [PATCH] Fix sidebar links to use absolute paths to prevent 404 errors

This change makes all sidebar navigation links absolute paths (starting with '/') instead of relative paths, preventing duplicate path segments when navigating between nested pages.

Added test to verify all sidebar links are absolute paths.

Fixes #1764
---
 src/renderer/html_handlebars/helpers/toc.rs |  3 ++-
 tests/testsuite/toc.rs                      | 23 +++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/renderer/html_handlebars/helpers/toc.rs b/src/renderer/html_handlebars/helpers/toc.rs
index a3419ce817..58dabf83b2 100644
--- a/src/renderer/html_handlebars/helpers/toc.rs
+++ b/src/renderer/html_handlebars/helpers/toc.rs
@@ -117,7 +117,8 @@ impl HelperDef for RenderToc {
                         // Hack for windows who tends to use `\` as separator instead of `/`
                         .replace('\\', "/");
 
-                    // Add link
+                    // Add link - prepend with / to make it an absolute path from site root
+                    out.write("/")?;
                     out.write(&tmp)?;
                     out.write(if is_toc_html {
                         "\" target=\"_parent\">"
diff --git a/tests/testsuite/toc.rs b/tests/testsuite/toc.rs
index eafbdc4857..519faad8d7 100644
--- a/tests/testsuite/toc.rs
+++ b/tests/testsuite/toc.rs
@@ -143,6 +143,29 @@ fn check_link_target_fallback() {
     );
 }
 
+// Checks that sidebar links are absolute paths (start with a forward slash).
+#[test]
+fn check_sidebar_links_are_absolute() {
+    let doc = toc_js_html();
+    
+    // Find all links in the chapter list
+    let links = doc.find(
+        Class("chapter")
+            .descendant(Name("li"))
+            .descendant(Name("a").and(Class("toggle").not()))
+    );
+    
+    // Go through each link and check if its href attribute starts with a slash
+    for link in links {
+        if let Some(href) = link.attr("href") {
+            if !href.is_empty() && !href.starts_with("#") {
+                // Skip anchor links and empty hrefs
+                assert!(href.starts_with("/"), "Link '{}' should be an absolute path starting with '/'.", href);
+            }
+        }
+    }
+}
+
 // Checks formatting of summary names with inline elements.
 #[test]
 fn summary_with_markdown_formatting() {