Don't try to render summary links as markdown.

src/book/book.rs

@@ -7,6 +7,7 @@ use std::path::{Path, PathBuf};
 use super::summary::{parse_summary, Link, SectionNumber, Summary, SummaryItem};
 use crate::config::BuildConfig;
 use crate::errors::*;
+use crate::utils::bracket_escape;
 
 /// Load a book into memory from its `src/` directory.
 pub fn load_book<P: AsRef<Path>>(src_dir: P, cfg: &BuildConfig) -> Result<Book> {
@@ -53,7 +54,7 @@ fn create_missing(src_dir: &Path, summary: &Summary) -> Result<()> {
                     let mut f = File::create(&filename).with_context(|| {
                         format!("Unable to create missing file: {}", filename.display())
                     })?;
-                    writeln!(f, "# {}", link.name)?;
+                    writeln!(f, "# {}", bracket_escape(&link.name))?;
                 }
             }
 

src/renderer/html_handlebars/helpers/toc.rs

@@ -1,11 +1,10 @@
 use std::collections::BTreeMap;
-use std::io;
 use std::path::Path;
 
 use crate::utils;
+use crate::utils::bracket_escape;
 
 use handlebars::{Context, Handlebars, Helper, HelperDef, Output, RenderContext, RenderError};
-use pulldown_cmark::{html, Event, Parser};
 
 // Handlebars helper to construct TOC
 #[derive(Clone, Copy)]
@@ -103,7 +102,7 @@ impl HelperDef for RenderToc {
             // Part title
             if let Some(title) = item.get("part") {
                 out.write("<li class=\"part-title\">")?;
-                write_escaped(out, title)?;
+                out.write(&bracket_escape(title))?;
                 out.write("</li>")?;
                 continue;
             }
@@ -148,20 +147,7 @@ impl HelperDef for RenderToc {
             }
 
             if let Some(name) = item.get("name") {
-                // Render only inline code blocks
-
-                // filter all events that are not inline code blocks
-                let parser = Parser::new(name).filter(|event| match *event {
-                    Event::Code(_) | Event::Html(_) | Event::Text(_) => true,
-                    _ => false,
-                });
-
-                // render markdown to html
-                let mut markdown_parsed_name = String::with_capacity(name.len() * 3 / 2);
-                html::push_html(&mut markdown_parsed_name, parser);
-
-                // write to the handlebars template
-                write_escaped(out, &markdown_parsed_name)?;
+                out.write(&bracket_escape(name))?
             }
 
             if path_exists {
@@ -205,18 +191,3 @@ fn write_li_open_tag(
     li.push_str("\">");
     out.write(&li)
 }
-
-fn write_escaped(out: &mut dyn Output, mut title: &str) -> io::Result<()> {
-    let needs_escape: &[char] = &['<', '>'];
-    while let Some(next) = title.find(needs_escape) {
-        out.write(&title[..next])?;
-        match title.as_bytes()[next] {
-            b'<' => out.write("&lt;")?,
-            b'>' => out.write("&gt;")?,
-            _ => unreachable!(),
-        }
-        title = &title[next + 1..];
-    }
-    out.write(title)?;
-    Ok(())
-}

src/utils/mod.rs

@@ -233,8 +233,26 @@ pub fn log_backtrace(e: &Error) {
     }
 }
 
+pub(crate) fn bracket_escape(mut s: &str) -> String {
+    let mut escaped = String::with_capacity(s.len());
+    let needs_escape: &[char] = &['<', '>'];
+    while let Some(next) = s.find(needs_escape) {
+        escaped.push_str(&s[..next]);
+        match s.as_bytes()[next] {
+            b'<' => escaped.push_str("&lt;"),
+            b'>' => escaped.push_str("&gt;"),
+            _ => unreachable!(),
+        }
+        s = &s[next + 1..];
+    }
+    escaped.push_str(s);
+    escaped
+}
+
 #[cfg(test)]
 mod tests {
+    use super::bracket_escape;
+
     mod render_markdown {
         use super::super::render_markdown;
 
@@ -431,4 +449,14 @@ more text with spaces
             assert_eq!(unique_id_from_content("## Über", &mut id_counter), "Über-2");
         }
     }
+
+    #[test]
+    fn escaped_brackets() {
+        assert_eq!(bracket_escape(""), "");
+        assert_eq!(bracket_escape("<"), "&lt;");
+        assert_eq!(bracket_escape(">"), "&gt;");
+        assert_eq!(bracket_escape("<>"), "&lt;&gt;");
+        assert_eq!(bracket_escape("<test>"), "&lt;test&gt;");
+        assert_eq!(bracket_escape("a<test>b"), "a&lt;test&gt;b");
+    }
 }

tests/dummy_book/summary-formatting/SUMMARY.md

@@ -0,0 +1,6 @@
+# Summary formatting tests
+
+- [*Italic* `code` \*escape\* \`escape2\`](formatted-summary.md)
+- [Soft
+line break](soft.md)
+- [\<escaped tag\>](escaped-tag.md)

tests/rendered_output.rs

@@ -621,6 +621,42 @@ fn remove_absolute_components(path: &Path) -> impl Iterator<Item = Component> +
     })
 }
 
+/// Checks formatting of summary names with inline elements.
+#[test]
+fn summary_with_markdown_formatting() {
+    let temp = DummyBook::new().build().unwrap();
+    let mut cfg = Config::default();
+    cfg.set("book.src", "summary-formatting").unwrap();
+    let md = MDBook::load_with_config(temp.path(), cfg).unwrap();
+    md.build().unwrap();
+
+    let rendered_path = temp.path().join("book/formatted-summary.html");
+    assert_contains_strings(
+        rendered_path,
+        &[
+            r#"<a href="formatted-summary.html" class="active"><strong aria-hidden="true">1.</strong> Italic code *escape* `escape2`</a>"#,
+            r#"<a href="soft.html"><strong aria-hidden="true">2.</strong> Soft line break</a>"#,
+            r#"<a href="escaped-tag.html"><strong aria-hidden="true">3.</strong> &lt;escaped tag&gt;</a>"#,
+        ],
+    );
+
+    let generated_md = temp.path().join("summary-formatting/formatted-summary.md");
+    assert_eq!(
+        fs::read_to_string(generated_md).unwrap(),
+        "# Italic code *escape* `escape2`\n"
+    );
+    let generated_md = temp.path().join("summary-formatting/soft.md");
+    assert_eq!(
+        fs::read_to_string(generated_md).unwrap(),
+        "# Soft line break\n"
+    );
+    let generated_md = temp.path().join("summary-formatting/escaped-tag.md");
+    assert_eq!(
+        fs::read_to_string(generated_md).unwrap(),
+        "# &lt;escaped tag&gt;\n"
+    );
+}
+
 #[cfg(feature = "search")]
 mod search {
     use crate::dummy_book::DummyBook;