fix: rebuild should reset module.preOrderIndex

crates/rspack_core/src/old_cache/local/code_splitting_cache.rs

@@ -7,7 +7,7 @@ use tracing::instrument;
 
 use crate::{
   build_chunk_graph::code_splitter::CodeSplitter, incremental::IncrementalPasses, Chunk,
-  ChunkGraph, ChunkGroup, ChunkGroupUkey, ChunkUkey, Compilation,
+  ChunkGraph, ChunkGroup, ChunkGroupUkey, ChunkUkey, Compilation, ModuleIdentifier,
 };
 
 #[derive(Debug, Default)]
@@ -20,6 +20,7 @@ pub struct CodeSplittingCache {
   named_chunk_groups: HashMap<String, ChunkGroupUkey>,
   named_chunks: HashMap<String, ChunkUkey>,
   pub(crate) code_splitter: CodeSplitter,
+  pub(crate) module_order_index: HashMap<ModuleIdentifier, (u32, u32)>,
 }
 
 #[instrument(skip_all)]
@@ -39,13 +40,15 @@ where
     return Ok(());
   }
 
+  // take to escape from borrow checker
+  let mut cache = std::mem::take(&mut compilation.code_splitting_cache);
+
   let has_change = compilation.has_module_import_export_change();
   if !has_change
     || compilation
       .incremental
       .can_read_mutations(IncrementalPasses::BUILD_CHUNK_GRAPH)
   {
-    let cache = &mut compilation.code_splitting_cache;
     rayon::scope(|s| {
       s.spawn(|_| compilation.chunk_by_ukey = cache.chunk_by_ukey.clone());
       s.spawn(|_| compilation.chunk_graph = cache.chunk_graph.clone());
@@ -56,13 +59,23 @@ where
       s.spawn(|_| compilation.named_chunks = cache.named_chunks.clone());
     });
 
+    // recover mgm.pre_order_index
+    let mut module_graph = compilation.get_module_graph_mut();
+    for (m, (pre_idx, post_idx)) in &cache.module_order_index {
+      let Some(mgm) = module_graph.module_graph_module_by_identifier_mut(m) else {
+        continue;
+      };
+      mgm.pre_order_index = Some(*pre_idx);
+      mgm.post_order_index = Some(*post_idx);
+    }
+
     if !has_change {
+      compilation.code_splitting_cache = cache;
       return Ok(());
     }
   }
 
   let compilation = task(compilation).await?;
-  let cache = &mut compilation.code_splitting_cache;
   rayon::scope(|s| {
     s.spawn(|_| cache.chunk_by_ukey = compilation.chunk_by_ukey.clone());
     s.spawn(|_| cache.chunk_graph = compilation.chunk_graph.clone());
@@ -72,5 +85,20 @@ where
     s.spawn(|_| cache.named_chunk_groups = compilation.named_chunk_groups.clone());
     s.spawn(|_| cache.named_chunks = compilation.named_chunks.clone());
   });
+
+  let module_graph = compilation.get_module_graph();
+  for id in module_graph.modules().keys() {
+    let Some(mgm) = module_graph.module_graph_module_by_identifier(id) else {
+      continue;
+    };
+
+    let (Some(pre_idx), Some(post_idx)) = (mgm.pre_order_index, mgm.post_order_index) else {
+      continue;
+    };
+
+    cache.module_order_index.insert(*id, (pre_idx, post_idx));
+  }
+
+  compilation.code_splitting_cache = cache;
   Ok(())
 }

crates/rspack_ids/src/deterministic_module_ids_plugin.rs

@@ -36,9 +36,7 @@ fn module_ids(&self, compilation: &mut Compilation) -> Result<()> {
     |m| get_full_module_name(m, context),
     |a, b| compare_modules_by_pre_order_index_or_identifier(&module_graph, a, b),
     |module, id| {
-      let size = used_ids.len();
-      used_ids.insert(id.to_string());
-      if used_ids.len() == size {
+      if !used_ids.insert(id.to_string()) {
         conflicts += 1;
         return false;
       }

packages/rspack-test-tools/tests/watchCases/split-chunks-incremental/pre-order-index/0/index.js

@@ -0,0 +1,5 @@
+import v from './lib'
+
+it('should compile', async () => {
+	expect(v).toBe(1)
+})

packages/rspack-test-tools/tests/watchCases/split-chunks-incremental/pre-order-index/0/lib.js

@@ -0,0 +1 @@
+export default 1;

packages/rspack-test-tools/tests/watchCases/split-chunks-incremental/pre-order-index/1/lib.js

@@ -0,0 +1,2 @@
+// change
+export default 1;

packages/rspack-test-tools/tests/watchCases/split-chunks-incremental/pre-order-index/rspack.config.js

@@ -0,0 +1,6 @@
+/** @type {import("@rspack/core").Configuration} */
+module.exports = {
+	optimization: {
+		splitChunks: false,
+	},
+};

packages/rspack-test-tools/tests/watchCases/split-chunks-incremental/pre-order-index/test.config.js

@@ -0,0 +1,10 @@
+module.exports = {
+	checkStats(_stepName, stats) {
+		// should keep module preOrderIndex and postOrderIndex during build
+		return [...stats.modules].filter(m => {
+			return m.moduleType !== 'runtime'
+		}).every((m) => {
+			return m.preOrderIndex !== undefined && m.postOrderIndex !== undefined
+		})
+	}
+}