Do not include optional crates that are not selected features

Author: shepmaster

top-crates/src/lib.rs

@@ -360,9 +360,10 @@ fn extend_direct_dependencies(
 ) {
     // Add a direct dependency on each starting crate.
     let mut summaries = Vec::new();
-    let mut valid_for_our_platform = BTreeSet::new();
+    let mut packages_to_build = BTreeSet::new();
+
     for dep in mem::take(crates).into_values() {
-        valid_for_our_platform.insert(dep.summary.package_id());
+        packages_to_build.insert(dep.summary.package_id());
         summaries.push((
             dep.summary,
             ResolveOpts {
@@ -391,20 +392,32 @@ fn extend_direct_dependencies(
     .expect("Unable to resolve dependencies");
 
     // Find transitive deps compatible with the playground's platform.
-    let mut to_visit = valid_for_our_platform.clone();
+    let mut to_visit = packages_to_build.clone();
     while !to_visit.is_empty() {
         let mut visit_next = BTreeSet::new();
 
         for package_id in to_visit {
+            let selected_features = resolve.features(package_id);
+
             for (dep_pkg, deps) in resolve.deps(package_id) {
-                let for_this_platform = deps.iter().any(|dep| {
-                    dep.platform().map_or(true, |platform| {
+                let will_be_built = deps.iter().any(|dep| {
+                    let selected_or_opted_in = match dep.is_optional() {
+                        false => true,
+                        true => {
+                            let name = dep.name_in_toml();
+                            selected_features.contains(&name)
+                        }
+                    };
+
+                    let for_this_platform = dep.platform().is_none_or(|platform| {
                         platform.matches(PLAYGROUND_TARGET_PLATFORM, global.target_info.cfg())
-                    })
+                    });
+
+                    selected_or_opted_in && for_this_platform
                 });
 
-                if for_this_platform {
-                    valid_for_our_platform.insert(dep_pkg);
+                if will_be_built {
+                    packages_to_build.insert(dep_pkg);
                     visit_next.insert(dep_pkg);
                 }
             }
@@ -416,7 +429,7 @@ fn extend_direct_dependencies(
     // Remove invalid and excluded packages that have been added due to resolution
     let package_ids = resolve
         .iter()
-        .filter(|pkg| valid_for_our_platform.contains(pkg))
+        .filter(|pkg| packages_to_build.contains(pkg))
         .filter(|pkg| !global.modifications.excluded(pkg.name().as_str()))
         .collect_vec();