diff --git a/crates/mdbook-html/src/utils.rs b/crates/mdbook-html/src/utils.rs
index 68f42a4094..9b75161c4b 100644
--- a/crates/mdbook-html/src/utils.rs
+++ b/crates/mdbook-html/src/utils.rs
@@ -83,7 +83,7 @@ pub(crate) fn id_from_content(content: &str) -> String {
// - https://pandoc.org/MANUAL.html#extension-auto_identifiers
// - https://kramdown.gettalong.org/converter/html#auto-ids
// - https://docs.rs/comrak/latest/comrak/options/struct.Extension.html#structfield.header_ids
- content
+ let id: String = content
.trim()
.to_lowercase()
.chars()
@@ -96,7 +96,16 @@ pub(crate) fn id_from_content(content: &str) -> String {
None
}
})
- .collect()
+ .collect();
+ // Headings consisting entirely of stripped characters (e.g. `## ::`) would
+ // otherwise produce an empty id and an empty `href="#"`, so fall back to
+ // "section" the way pandoc and kramdown do. `unique_id` will append a
+ // numeric suffix when the same fallback is used more than once.
+ if id.is_empty() {
+ String::from("section")
+ } else {
+ id
+ }
}
#[cfg(test)]
@@ -128,8 +137,32 @@ mod tests {
assert_eq!(id_from_content("中文"), "中文");
assert_eq!(id_from_content("にほんご"), "にほんご");
assert_eq!(id_from_content("한국어"), "한국어");
- assert_eq!(id_from_content(""), "");
+ assert_eq!(id_from_content(""), "section");
+ assert_eq!(id_from_content("::"), "section");
+ assert_eq!(id_from_content("!.():"), "section");
+ assert_eq!(id_from_content(" "), "section");
assert_eq!(id_from_content("中文標題 CJK title"), "中文標題-cjk-title");
assert_eq!(id_from_content("Über"), "über");
}
+
+ #[test]
+ fn punctuation_only_headings_get_unique_section_ids() {
+ let mut id_counter = Default::default();
+ assert_eq!(
+ unique_id(&id_from_content("::"), &mut id_counter),
+ "section"
+ );
+ assert_eq!(
+ unique_id(&id_from_content("!!!"), &mut id_counter),
+ "section-1"
+ );
+ assert_eq!(
+ unique_id(&id_from_content("Real Heading"), &mut id_counter),
+ "real-heading"
+ );
+ assert_eq!(
+ unique_id(&id_from_content("***"), &mut id_counter),
+ "section-2"
+ );
+ }
}
diff --git a/tests/testsuite/rendering/header_links/expected/header_links.html b/tests/testsuite/rendering/header_links/expected/header_links.html
index 29c35a530d..2b466df55c 100644
--- a/tests/testsuite/rendering/header_links/expected/header_links.html
+++ b/tests/testsuite/rendering/header_links/expected/header_links.html
@@ -1,7 +1,7 @@
-
-
+
+