Rollup merge of #93576 - jsha:fix-rustdoc-html, r=GuillaumeGomez

Emit more valid HTML from rustdoc

Previously, tidy-html5 (`tidy`) would complain about a few things in our HTML. The main thing is that `<summary>` tags can't contain `<div>`s. That's easily fixed by changing out the `<div>`s for `<span>`s with `display: block`.

However, there's also a rule that `<span>`s can't contain heading elements. `<span>` permits only "phrasing content" https://developer.mozilla.org/en-US/docs/Web/HTML/Element/span, and `<h3>` (and friends) are "Flow content, heading content, palpable content". https://developer.mozilla.org/en-US/docs/Web/HTML/Element/Heading_Elements

We have a wrapping `<div>` that goes around each `<h3>`/`<h4>`, etc. We turn that into a `<section>` rather than a `<span>` because `<section>` permits "flow content". https://developer.mozilla.org/en-US/docs/Web/HTML/Element/section

After this change we get only three warnings from tidy, run on struct.String.html:

line 6 column 10790 - Warning: trimming empty <span>
line 1 column 1118 - Warning: <link> proprietary attribute "disabled"
line 1 column 1193 - Warning: <link> proprietary attribute "disabled"

The empty `<span>` is a known issue - there's a span in front of the search box to work around a strange Safari issue.

The `<link>` attributes are the non-default stylesheets. We can probably refactor theme application to avoid using this proprietary "disabled" attribute.

We can suppress those warnings with flags to tidy, and get a run that returns 0 (success):

```
tidy -o /dev/null -quiet --drop-empty-elements no --warn-proprietary-attributes no build/x86_64-unknown-linux-gnu/doc/std/string/trait.ToString.html
```

Note: this requires the latest version of tidy-html5, built from https://github.com/htacg/tidy-html5. Older versions (including the default version on Ubuntu 21.10) think `<section>` can't occur inside `<summary>`.

Demo: https://rustdoc.crud.net/jsha/fix-rustdoc-html/std/string/struct.String.html

r? `@GuillaumeGomez`

1 files changed, 27 insertions, 35 deletions

diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index 59a6187b62b..f3e65df6b14 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -1265,7 +1265,7 @@ fn notable_traits_decl(decl: &clean::FnDecl, cx: &Context<'_>) -> String {
                         if out.is_empty() {
                             write!(
                                 &mut out,
-                                "<div class=\"notable\">Notable traits for {}</div>\
+                                "<span class=\"notable\">Notable traits for {}</span>\
                              <code class=\"content\">",
                                 impl_.for_.print(cx)
                             );
@@ -1297,9 +1297,9 @@ fn notable_traits_decl(decl: &clean::FnDecl, cx: &Context<'_>) -> String {
         out.insert_str(
             0,
             "<span class=\"notable-traits\"><span class=\"notable-traits-tooltip\">ⓘ\
-            <div class=\"notable-traits-tooltiptext\"><span class=\"docblock\">",
+            <span class=\"notable-traits-tooltiptext\"><span class=\"docblock\">",
         );
-        out.push_str("</code></span></div></span></span>");
+        out.push_str("</code></span></span></span></span>");
     }
 
     out.into_inner()
@@ -1431,7 +1431,7 @@ fn render_impl(
                         .map(|item| format!("{}.{}", item.type_(), name));
                     write!(
                         w,
-                        "<div id=\"{}\" class=\"{}{} has-srclink\">",
+                        "<section id=\"{}\" class=\"{}{} has-srclink\">",
                         id, item_type, in_trait_class,
                     );
                     render_rightside(w, cx, item, containing_item, render_mode);
@@ -1446,7 +1446,7 @@ fn render_impl(
                         render_mode,
                     );
                     w.write_str("</h4>");
-                    w.write_str("</div>");
+                    w.write_str("</section>");
                 }
             }
             clean::TypedefItem(ref tydef, _) => {
@@ -1454,7 +1454,7 @@ fn render_impl(
                 let id = cx.derive_id(source_id.clone());
                 write!(
                     w,
-                    "<div id=\"{}\" class=\"{}{} has-srclink\">",
+                    "<section id=\"{}\" class=\"{}{} has-srclink\">",
                     id, item_type, in_trait_class
                 );
                 write!(w, "<a href=\"#{}\" class=\"anchor\"></a>", id);
@@ -1469,14 +1469,14 @@ fn render_impl(
                     cx,
                 );
                 w.write_str("</h4>");
-                w.write_str("</div>");
+                w.write_str("</section>");
             }
             clean::AssocConstItem(ref ty, _) => {
                 let source_id = format!("{}.{}", item_type, name);
                 let id = cx.derive_id(source_id.clone());
                 write!(
                     w,
-                    "<div id=\"{}\" class=\"{}{} has-srclink\">",
+                    "<section id=\"{}\" class=\"{}{} has-srclink\">",
                     id, item_type, in_trait_class
                 );
                 render_rightside(w, cx, item, containing_item, render_mode);
@@ -1491,12 +1491,12 @@ fn render_impl(
                     cx,
                 );
                 w.write_str("</h4>");
-                w.write_str("</div>");
+                w.write_str("</section>");
             }
             clean::AssocTypeItem(ref bounds, ref default) => {
                 let source_id = format!("{}.{}", item_type, name);
                 let id = cx.derive_id(source_id.clone());
-                write!(w, "<div id=\"{}\" class=\"{}{}\">", id, item_type, in_trait_class,);
+                write!(w, "<section id=\"{}\" class=\"{}{}\">", id, item_type, in_trait_class,);
                 write!(w, "<a href=\"#{}\" class=\"anchor\"></a>", id);
                 w.write_str("<h4 class=\"code-header\">");
                 assoc_type(
@@ -1509,7 +1509,7 @@ fn render_impl(
                     cx,
                 );
                 w.write_str("</h4>");
-                w.write_str("</div>");
+                w.write_str("</section>");
             }
             clean::StrippedItem(..) => return,
             _ => panic!("can't make docs for trait item with name {:?}", item.name),
@@ -1668,21 +1668,23 @@ fn render_rightside(
         RenderMode::ForDeref { .. } => (None, None),
     };
 
-    write!(w, "<div class=\"rightside\">");
+    let mut rightside = Buffer::new();
     let has_stability = render_stability_since_raw(
-        w,
+        &mut rightside,
         item.stable_since(tcx),
         const_stability,
         containing_item.stable_since(tcx),
         const_stable_since,
     );
-    let mut tmp_buf = Buffer::empty_from(w);
-    write_srclink(cx, item, &mut tmp_buf);
-    if has_stability && !tmp_buf.is_empty() {
-        w.write_str(" · ");
+    let mut srclink = Buffer::empty_from(w);
+    write_srclink(cx, item, &mut srclink);
+    if has_stability && !srclink.is_empty() {
+        rightside.write_str(" · ");
+    }
+    rightside.push_buffer(srclink);
+    if !rightside.is_empty() {
+        write!(w, "<span class=\"rightside\">{}</span>", rightside.into_inner());
     }
-    w.push_buffer(tmp_buf);
-    w.write_str("</div>");
 }
 
 pub(crate) fn render_impl_summary(
@@ -1713,7 +1715,7 @@ pub(crate) fn render_impl_summary(
     } else {
         format!(" data-aliases=\"{}\"", aliases.join(","))
     };
-    write!(w, "<div id=\"{}\" class=\"impl has-srclink\"{}>", id, aliases);
+    write!(w, "<section id=\"{}\" class=\"impl has-srclink\"{}>", id, aliases);
     render_rightside(w, cx, &i.impl_item, containing_item, RenderMode::Normal);
     write!(w, "<a href=\"#{}\" class=\"anchor\"></a>", id);
     write!(w, "<h3 class=\"code-header in-band\">");
@@ -1737,11 +1739,11 @@ pub(crate) fn render_impl_summary(
     let is_trait = i.inner_impl().trait_.is_some();
     if is_trait {
         if let Some(portability) = portability(&i.impl_item, Some(parent)) {
-            write!(w, "<div class=\"item-info\">{}</div>", portability);
+            write!(w, "<span class=\"item-info\">{}</span>", portability);
         }
     }
 
-    w.write_str("</div>");
+    w.write_str("</section>");
 }
 
 fn print_sidebar(cx: &Context<'_>, it: &clean::Item, buffer: &mut Buffer) {
@@ -1802,19 +1804,9 @@ fn print_sidebar(cx: &Context<'_>, it: &clean::Item, buffer: &mut Buffer) {
     // to navigate the documentation (though slightly inefficiently).
 
     if !it.is_mod() {
-        buffer.write_str("<h2 class=\"location\">In ");
-        for (i, name) in cx.current.iter().take(parentlen).enumerate() {
-            if i > 0 {
-                buffer.write_str("::<wbr>");
-            }
-            write!(
-                buffer,
-                "<a href=\"{}index.html\">{}</a>",
-                &cx.root_path()[..(cx.current.len() - i - 1) * 3],
-                *name
-            );
-        }
-        buffer.write_str("</h2>");
+        let path: String = cx.current.iter().map(|s| s.as_str()).intersperse("::").collect();
+
+        write!(buffer, "<h2 class=\"location\"><a href=\"index.html\">In {}</a></h2>", path);
     }
 
     // Sidebar refers to the enclosing module, not this module.