Rollup merge of #92146 - willcrichton:example-analyzer, r=jyn514

Don't emit shared files when scraping examples from dependencies in Rustdoc

This PR fixes #91605. The issue is that `Context::init` gets called when scraping dependencies. By default, just calling `init` calls into `write_shared` and `build_index` which register the scraped crate into a list that later gets used for the Rustdoc sidebar. The fix is to ensure that `write_shared` is not called when scraping.

r? `@jyn514`

src/librustdoc/html/render/context.rs

@@ -397,6 +397,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
             show_type_layout,
             generate_link_to_definition,
             call_locations,
+            no_emit_shared,
             ..
         } = options;
 
@@ -516,13 +517,16 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
             sources::render(&mut cx, &krate)?;
         }
 
-        // Build our search index
-        let index = build_index(&krate, &mut Rc::get_mut(&mut cx.shared).unwrap().cache, tcx);
+        if !no_emit_shared {
+            // Build our search index
+            let index = build_index(&krate, &mut Rc::get_mut(&mut cx.shared).unwrap().cache, tcx);
+
+            // Write shared runs within a flock; disable thread dispatching of IO temporarily.
+            Rc::get_mut(&mut cx.shared).unwrap().fs.set_sync_only(true);
+            write_shared(&cx, &krate, index, &md_opts)?;
+            Rc::get_mut(&mut cx.shared).unwrap().fs.set_sync_only(false);
+        }
 
-        // Write shared runs within a flock; disable thread dispatching of IO temporarily.
-        Rc::get_mut(&mut cx.shared).unwrap().fs.set_sync_only(true);
-        write_shared(&cx, &krate, index, &md_opts)?;
-        Rc::get_mut(&mut cx.shared).unwrap().fs.set_sync_only(false);
         Ok((cx, krate))
     }