fix(mf): preserve consume fallback source emission

Emit consume-shared source data for shared consumers and let the runtime module reuse it when serializing consume metadata. This keeps module-output consume entries callable so layered federation consumers can initialize sharing before resolving shared react.

Made-with: Cursor

Author: ScriptedAlchemy

crates/rspack_plugin_mf/src/sharing/consume_shared_module.rs

@@ -8,7 +8,8 @@ use rspack_core::{
   BuildInfo, BuildMeta, BuildResult, CodeGenerationResult, Compilation, Context, DependenciesBlock,
   DependencyId, ExportsType, FactoryMeta, LibIdentOptions, Module, ModuleCodeGenerationContext,
   ModuleGraph, ModuleIdentifier, ModuleLayer, ModuleType, RuntimeGlobals, RuntimeSpec, SourceType,
-  impl_module_meta_info, impl_source_map_config, module_update_hash, rspack_sources::BoxSource,
+  impl_module_meta_info, impl_source_map_config, module_update_hash,
+  rspack_sources::{BoxSource, RawStringSource, SourceExt},
 };
 use rspack_error::{Result, impl_empty_diagnosable_trait};
 use rspack_hash::{RspackHash, RspackHashDigest};
@@ -252,6 +253,16 @@ impl Module for ConsumeSharedModule {
         runtime_template.async_module_factory(&self.get_blocks()[0], fallback, compilation)
       }
     });
+    code_generation_result.add(
+      SourceType::ConsumeShared,
+      RawStringSource::from(factory.clone().unwrap_or_else(|| {
+        format!(
+          "()=>()=>{{throw new Error(\"Can not get '{}' \")}}",
+          self.options.share_key
+        )
+      }))
+      .boxed(),
+    );
     code_generation_result
       .data
       .insert(CodeGenerationDataConsumeShared {

crates/rspack_plugin_mf/src/sharing/consume_shared_runtime_module.rs

@@ -102,6 +102,9 @@ impl RuntimeModule for ConsumeSharedRuntimeModule {
         .code_generation_results
         .get(&module, Some(chunk.runtime()));
       if let Some(data) = code_gen.data.get::<CodeGenerationDataConsumeShared>() {
+        let fallback_source = code_gen
+          .get(&SourceType::ConsumeShared)
+          .map(|source| source.source().into_string_lossy().into_owned());
         let share_scope_json = if enhanced {
           json_stringify(&data.share_scope)
         } else {
@@ -133,7 +136,11 @@ impl RuntimeModule for ConsumeSharedRuntimeModule {
           json_stringify(&data.singleton),
           json_stringify(&data.eager),
           layer_data,
-          data.fallback.as_deref().unwrap_or("undefined"),
+          data
+            .fallback
+            .as_deref()
+            .or(fallback_source.as_deref())
+            .unwrap_or("undefined"),
           json_stringify(&data.tree_shaking_mode),
         ));
       }