rustdoc: sort deprecated items lower in search

serialize `q` (`itemPaths`) sparsely
overall 4% reduction in search index size

src/librustdoc/formats/cache.rs

@@ -337,6 +337,7 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
                                     self.cache,
                                 ),
                                 aliases: item.attrs.get_doc_aliases(),
+                                deprecation: item.deprecation(self.tcx),
                             });
                         }
                     }

src/librustdoc/html/render/mod.rs

@@ -107,6 +107,7 @@ pub(crate) struct IndexItem {
     pub(crate) parent_idx: Option<usize>,
     pub(crate) search_type: Option<IndexItemFunctionType>,
     pub(crate) aliases: Box<[Symbol]>,
+    pub(crate) deprecation: Option<Deprecation>,
 }
 
 /// A type used for the search index.

src/librustdoc/html/render/print_item.rs

@@ -470,10 +470,11 @@ fn extra_info_tags(item: &clean::Item, parent: &clean::Item, tcx: TyCtxt<'_>) ->
 
     // The trailing space after each tag is to space it properly against the rest of the docs.
     if let Some(depr) = &item.deprecation(tcx) {
-        let mut message = "Deprecated";
-        if !stability::deprecation_in_effect(depr) {
-            message = "Deprecation planned";
-        }
+        let message = if stability::deprecation_in_effect(depr) {
+            "Deprecated"
+        } else {
+            "Deprecation planned"
+        };
         tags += &tag_html("deprecated", "", message);
     }
 

src/librustdoc/html/render/search_index.rs

@@ -42,6 +42,7 @@ pub(crate) fn build_index<'tcx>(
                 parent_idx: None,
                 search_type: get_function_type_for_search(item, tcx, impl_generics.as_ref(), cache),
                 aliases: item.attrs.get_doc_aliases(),
+                deprecation: item.deprecation(tcx),
             });
         }
     }
@@ -244,7 +245,17 @@ pub(crate) fn build_index<'tcx>(
             )?;
             crate_data.serialize_field(
                 "q",
-                &self.items.iter().map(|item| &item.path).collect::<Vec<_>>(),
+                &self
+                    .items
+                    .iter()
+                    .enumerate()
+                    // Serialize as an array of item indices and full paths
+                    .filter_map(
+                        |(index, item)| {
+                            if item.path.is_empty() { None } else { Some((index, &item.path)) }
+                        },
+                    )
+                    .collect::<Vec<_>>(),
             )?;
             crate_data.serialize_field(
                 "d",
@@ -297,6 +308,16 @@ pub(crate) fn build_index<'tcx>(
                     })
                     .collect::<Vec<_>>(),
             )?;
+            crate_data.serialize_field(
+                "c",
+                &self
+                    .items
+                    .iter()
+                    .enumerate()
+                    // Serialize as an array of deprecated item indices
+                    .filter_map(|(index, item)| item.deprecation.map(|_| index))
+                    .collect::<Vec<_>>(),
+            )?;
             crate_data.serialize_field(
                 "p",
                 &self.paths.iter().map(|(it, s)| (it, s.as_str())).collect::<Vec<_>>(),

src/librustdoc/html/static/js/search.js

@@ -811,6 +811,13 @@ function initSearch(rawSearchIndex) {
                     return a - b;
                 }
 
+                // sort deprecated items later
+                a = aaa.item.deprecated;
+                b = bbb.item.deprecated;
+                if (a !== b) {
+                    return a - b;
+                }
+
                 // sort by crate (current crate comes first)
                 a = (aaa.item.crate !== preferredCrate);
                 b = (bbb.item.crate !== preferredCrate);
@@ -1170,6 +1177,7 @@ function initSearch(rawSearchIndex) {
                 parent: item.parent,
                 type: item.type,
                 is_alias: true,
+                deprecated: item.deprecated,
             };
         }
 
@@ -1965,10 +1973,11 @@ function initSearch(rawSearchIndex) {
              *   n: Array<string>,
              *   t: Array<Number>,
              *   d: Array<string>,
-             *   q: Array<string>,
+             *   q: Array<[Number, string]>,
              *   i: Array<Number>,
              *   f: Array<RawFunctionSearchType>,
              *   p: Array<Object>,
+             *   c: Array<Number>
              * }}
              */
             const crateCorpus = rawSearchIndex[crate];
@@ -1987,6 +1996,7 @@ function initSearch(rawSearchIndex) {
                 type: null,
                 id: id,
                 normalizedName: crate.indexOf("_") === -1 ? crate : crate.replace(/_/g, ""),
+                deprecated: null,
             };
             id += 1;
             searchIndex.push(crateRow);
@@ -1996,14 +2006,20 @@ function initSearch(rawSearchIndex) {
             const itemTypes = crateCorpus.t;
             // an array of (String) item names
             const itemNames = crateCorpus.n;
-            // an array of (String) full paths (or empty string for previous path)
-            const itemPaths = crateCorpus.q;
+            // an array of [(Number) item index,
+            //              (String) full path]
+            // an item whose index is not present will fall back to the previous present path
+            // i.e. if indices 4 and 11 are present, but 5-10 and 12-13 are not present,
+            // 5-10 will fall back to the path for 4 and 12-13 will fall back to the path for 11
+            const itemPaths = new Map(crateCorpus.q);
             // an array of (String) descriptions
             const itemDescs = crateCorpus.d;
             // an array of (Number) the parent path index + 1 to `paths`, or 0 if none
             const itemParentIdxs = crateCorpus.i;
             // an array of (Object | null) the type of the function, if any
             const itemFunctionSearchTypes = crateCorpus.f;
+            // an array of (Number) indices for the deprecated items
+            const deprecatedItems = new Set(crateCorpus.c);
             // an array of [(Number) item type,
             //              (String) name]
             const paths = crateCorpus.p;
@@ -2045,12 +2061,13 @@ function initSearch(rawSearchIndex) {
                     crate: crate,
                     ty: itemTypes[i],
                     name: itemNames[i],
-                    path: itemPaths[i] ? itemPaths[i] : lastPath,
+                    path: itemPaths.has(i) ? itemPaths.get(i) : lastPath,
                     desc: itemDescs[i],
                     parent: itemParentIdxs[i] > 0 ? paths[itemParentIdxs[i] - 1] : undefined,
                     type: buildFunctionSearchType(itemFunctionSearchTypes[i], lowercasePaths),
                     id: id,
                     normalizedName: word.indexOf("_") === -1 ? word : word.replace(/_/g, ""),
+                    deprecated: deprecatedItems.has(i),
                 };
                 id += 1;
                 searchIndex.push(row);