rustdoc: account for intra-doc links in <meta name="description">

Author: notriddle

src/librustdoc/html/markdown.rs

@@ -1180,14 +1180,23 @@ pub(crate) fn short_markdown_summary(markdown: &str, link_names: &[RenderedLink]
 /// - Headings, links, and formatting are stripped.
 /// - Inline code is rendered as-is, surrounded by backticks.
 /// - HTML and code blocks are ignored.
-pub(crate) fn plain_text_summary(md: &str) -> String {
+pub(crate) fn plain_text_summary(md: &str, link_names: &[RenderedLink]) -> String {
     if md.is_empty() {
         return String::new();
     }
 
     let mut s = String::with_capacity(md.len() * 3 / 2);
 
-    for event in Parser::new_ext(md, summary_opts()) {
+    let mut replacer = |broken_link: BrokenLink<'_>| {
+        link_names
+            .iter()
+            .find(|link| link.original_text.as_str() == &*broken_link.reference)
+            .map(|link| (link.href.as_str().into(), link.new_text.as_str().into()))
+    };
+
+    let p = Parser::new_with_broken_link_callback(md, summary_opts(), Some(&mut replacer));
+
+    for event in p {
         match &event {
             Event::Text(text) => s.push_str(text),
             Event::Code(code) => {

src/librustdoc/html/markdown/tests.rs

@@ -249,7 +249,7 @@ fn test_short_markdown_summary() {
 #[test]
 fn test_plain_text_summary() {
     fn t(input: &str, expect: &str) {
-        let output = plain_text_summary(input);
+        let output = plain_text_summary(input, &[]);
         assert_eq!(output, expect, "original: {}", input);
     }
 

src/librustdoc/html/render/context.rs

@@ -182,7 +182,10 @@ impl<'tcx> Context<'tcx> {
         };
         title.push_str(" - Rust");
         let tyname = it.type_();
-        let desc = it.doc_value().as_ref().map(|doc| plain_text_summary(doc));
+        let desc = it
+            .doc_value()
+            .as_ref()
+            .map(|doc| plain_text_summary(doc, &it.link_names(&self.cache())));
         let desc = if let Some(desc) = desc {
             desc
         } else if it.is_crate() {

tests/rustdoc/description.rs

@@ -22,3 +22,9 @@ pub mod foo_mod {
 //   'Only paragraph.'
 /// Only paragraph.
 pub fn foo_fn() {}
+
+// @has 'foo/fn.bar_fn.html' '//meta[@name="description"]/@content' \
+//   'Description with intra-doc link to foo_fn and [nonexistent_item] and foo_fn.'
+#[allow(rustdoc::broken_intra_doc_links)]
+/// Description with intra-doc link to [foo_fn] and [nonexistent_item] and [foo_fn](self::foo_fn).
+pub fn bar_fn() {}