fix(mf): resolve version from parent package for secondary entry points

When a secondary entry point (e.g. `@mui/material/styles`) has its own
`package.json` without a `version` field, ProvideSharedPlugin now walks
up the directory tree to find the parent package's version instead of
emitting a warning. This matches the behavior expected for packages that
use the secondary entry point pattern (MUI, Emotion, Apollo Client, etc).

The fix validates the relationship by checking that the shared key
exactly equals `<parent_name>/<relative_path>` and stops at the
`node_modules` boundary.

Fixes: webpack/webpack#15864
Ref: webpack/webpack#13457
Made-with: Cursor

Author: davidfestal

crates/rspack_plugin_mf/src/sharing/provide_shared_plugin.rs

@@ -1,5 +1,6 @@
 use std::{
   fmt,
+  path::Path,
   sync::{Arc, LazyLock},
 };
 
@@ -101,6 +102,40 @@ impl ProvideSharedPlugin {
     )
   }
 
+  /// For secondary entry points (e.g. `@mui/material/styles`) whose own
+  /// `package.json` has no `version`, walk up to the parent package and use
+  /// its version — but only when the shared key matches
+  /// `<parent_name>/<relative_path>`.
+  fn find_parent_package_version(description_path: &Path, key: &str) -> Option<String> {
+    let entry_dir = description_path.parent()?;
+    let mut search_dir = entry_dir.parent();
+
+    while let Some(dir) = search_dir {
+      if dir.file_name().is_some_and(|n| n == "node_modules") {
+        break;
+      }
+
+      let parent_pkg = dir.join("package.json");
+      if parent_pkg.exists() {
+        if let Ok(data) = std::fs::read(&parent_pkg)
+          && let Ok(parent) = serde_json::from_slice::<serde_json::Value>(&data)
+          && let Some(parent_name) = parent.get("name").and_then(|n| n.as_str())
+          && let Some(parent_version) = parent.get("version").and_then(|v| v.as_str())
+        {
+          if let Ok(rel) = entry_dir.strip_prefix(dir) {
+            let expected_key = format!("{parent_name}/{}", rel.to_string_lossy());
+            if key == expected_key {
+              return Some(parent_version.to_string());
+            }
+          }
+        }
+      }
+      search_dir = dir.parent();
+    }
+
+    None
+  }
+
   #[allow(clippy::too_many_arguments)]
   pub async fn provide_shared_module(
     &self,
@@ -134,16 +169,21 @@ impl ProvideSharedPlugin {
         },
       );
     } else if let Some(description) = resource_data.description() {
-      if let Some(description) = description.json().as_object()
-        && let Some(version) = description.get("version")
-        && let Some(version) = version.as_str()
-      {
+      let version = description
+        .json()
+        .as_object()
+        .and_then(|d| d.get("version"))
+        .and_then(|v| v.as_str())
+        .map(|v| v.to_string())
+        .or_else(|| Self::find_parent_package_version(description.path(), key));
+
+      if let Some(version) = version {
         self.resolved_provide_map.write().await.insert(
           resource.to_string(),
           VersionedProvideOptions {
             share_key: share_key.to_string(),
             share_scope: share_scope.clone(),
-            version: ProvideVersion::Version(version.to_string()),
+            version: ProvideVersion::Version(version),
             eager,
             singleton,
             strict_version,

tests/rspack-test/configCases/sharing/share-plugin-secondary-entry-point/index.js

@@ -0,0 +1,17 @@
+it("should provide a secondary entry point using the parent package version", async () => {
+	const styles = await import("@scope/pkg/styles");
+	expect(styles).toEqual(
+		expect.objectContaining({
+			default: "pkg-styles"
+		})
+	);
+});
+
+it("should provide the root package normally", async () => {
+	const pkg = await import("@scope/pkg");
+	expect(pkg).toEqual(
+		expect.objectContaining({
+			default: "pkg-root"
+		})
+	);
+});

tests/rspack-test/configCases/sharing/share-plugin-secondary-entry-point/node_modules/@scope/pkg/index.js

@@ -0,0 +1,15 @@
+const { SharePlugin } = require("@rspack/core").sharing;
+
+/** @type {import("@rspack/core").Configuration} */
+module.exports = {
+	mode: "development",
+	devtool: false,
+	plugins: [
+		new SharePlugin({
+			shared: {
+				"@scope/pkg": {},
+				"@scope/pkg/styles": {}
+			}
+		})
+	]
+};