OutputAsset trait (#5507)

### Description

adding a trait to all assets in the output graph

next.js PR: vercel/next.js#52606

crates/node-file-trace/src/nft_json.rs

@@ -4,6 +4,7 @@ use turbo_tasks_fs::{File, FileSystem};
 use turbopack_core::{
     asset::{Asset, AssetContentVc, AssetVc},
     ident::AssetIdentVc,
+    output::{OutputAsset, OutputAssetVc},
     reference::all_assets,
 };
 
@@ -20,6 +21,9 @@ impl NftJsonAssetVc {
     }
 }
 
+#[turbo_tasks::value_impl]
+impl OutputAsset for NftJsonAsset {}
+
 #[turbo_tasks::value_impl]
 impl Asset for NftJsonAsset {
     #[turbo_tasks::function]

crates/turbopack-build/src/chunking_context.rs

@@ -7,13 +7,14 @@ use turbo_tasks::{
 };
 use turbo_tasks_fs::FileSystemPathVc;
 use turbopack_core::{
-    asset::{Asset, AssetVc, AssetsVc},
+    asset::{Asset, AssetVc},
     chunk::{
         Chunk, ChunkVc, ChunkableModule, ChunkingContext, ChunkingContextVc, ChunksVc,
         EvaluatableAssetsVc,
     },
     environment::EnvironmentVc,
     ident::AssetIdentVc,
+    output::{OutputAssetVc, OutputAssetsVc},
 };
 use turbopack_css::chunk::CssChunkVc;
 use turbopack_ecmascript::chunk::{
@@ -119,7 +120,7 @@ impl BuildChunkingContextVc {
         path: FileSystemPathVc,
         module: EcmascriptChunkPlaceableVc,
         evaluatable_assets: EvaluatableAssetsVc,
-    ) -> Result<AssetVc> {
+    ) -> Result<OutputAssetVc> {
         let entry_chunk = module.as_root_chunk(self_vc.into());
 
         let other_chunks = self_vc
@@ -129,7 +130,7 @@ impl BuildChunkingContextVc {
         let asset = EcmascriptBuildNodeEntryChunkVc::new(
             path,
             self_vc,
-            AssetsVc::cell(other_chunks),
+            OutputAssetsVc::cell(other_chunks),
             evaluatable_assets,
             module,
         )
@@ -139,12 +140,14 @@ impl BuildChunkingContextVc {
     }
 
     #[turbo_tasks::function]
-    async fn generate_chunk(self, chunk: ChunkVc) -> Result<AssetVc> {
+    async fn generate_chunk(self, chunk: ChunkVc) -> Result<OutputAssetVc> {
         Ok(
             if let Some(ecmascript_chunk) = EcmascriptChunkVc::resolve_from(chunk).await? {
                 EcmascriptBuildNodeChunkVc::new(self, ecmascript_chunk).into()
+            } else if let Some(output_asset) = OutputAssetVc::resolve_from(chunk).await? {
+                output_asset
             } else {
-                chunk.into()
+                bail!("Unable to generate output asset for chunk");
             },
         )
     }
@@ -155,7 +158,7 @@ impl BuildChunkingContextVc {
         self,
         entry_chunk: ChunkVc,
         evaluatable_assets: EvaluatableAssetsVc,
-    ) -> Result<Vec<AssetVc>> {
+    ) -> Result<Vec<OutputAssetVc>> {
         let evaluatable_assets_ref = evaluatable_assets.await?;
 
         let mut chunks: IndexSet<_> = evaluatable_assets_ref
@@ -270,26 +273,26 @@ impl ChunkingContext for BuildChunkingContext {
     async fn chunk_group(
         self_vc: BuildChunkingContextVc,
         entry_chunk: ChunkVc,
-    ) -> Result<AssetsVc> {
+    ) -> Result<OutputAssetsVc> {
         let parallel_chunks = get_parallel_chunks([entry_chunk]).await?;
 
         let optimized_chunks = get_optimized_chunks(parallel_chunks).await?;
 
-        let assets: Vec<AssetVc> = optimized_chunks
+        let assets: Vec<OutputAssetVc> = optimized_chunks
             .await?
             .iter()
             .map(|chunk| self_vc.generate_chunk(*chunk))
             .collect();
 
-        Ok(AssetsVc::cell(assets))
+        Ok(OutputAssetsVc::cell(assets))
     }
 
     #[turbo_tasks::function]
     async fn evaluated_chunk_group(
         _self_vc: BuildChunkingContextVc,
         _entry_chunk: ChunkVc,
         _evaluatable_assets: EvaluatableAssetsVc,
-    ) -> Result<AssetsVc> {
+    ) -> Result<OutputAssetsVc> {
         // TODO(alexkirsz) This method should be part of a separate trait that is
         // only implemented for client/edge runtimes.
         bail!("the build chunking context does not support evaluated chunk groups")

crates/turbopack-build/src/ecmascript/node/chunk.rs

@@ -6,6 +6,7 @@ use turbopack_core::{
     chunk::ChunkingContext,
     ident::AssetIdentVc,
     introspect::{Introspectable, IntrospectableChildrenVc, IntrospectableVc},
+    output::{OutputAsset, OutputAssetVc},
     reference::AssetReferencesVc,
     source_map::{
         GenerateSourceMap, GenerateSourceMapVc, OptionSourceMapVc, SourceMapAssetReferenceVc,
@@ -62,6 +63,9 @@ impl EcmascriptBuildNodeChunkVc {
     }
 }
 
+#[turbo_tasks::value_impl]
+impl OutputAsset for EcmascriptBuildNodeChunk {}
+
 #[turbo_tasks::value_impl]
 impl Asset for EcmascriptBuildNodeChunk {
     #[turbo_tasks::function]

crates/turbopack-build/src/ecmascript/node/entry/chunk.rs

@@ -5,10 +5,11 @@ use indoc::writedoc;
 use turbo_tasks::{primitives::StringVc, ValueToString, ValueToStringVc};
 use turbo_tasks_fs::{File, FileSystemPathVc};
 use turbopack_core::{
-    asset::{Asset, AssetContentVc, AssetVc, AssetsVc},
+    asset::{Asset, AssetContentVc, AssetVc},
     chunk::{ChunkingContext, EvaluatableAssetsVc},
     code_builder::{CodeBuilder, CodeVc},
     ident::AssetIdentVc,
+    output::{OutputAsset, OutputAssetVc, OutputAssetsVc},
     reference::{AssetReferencesVc, SingleAssetReferenceVc},
     source_map::{
         GenerateSourceMap, GenerateSourceMapVc, OptionSourceMapVc, SourceMapAssetReferenceVc,
@@ -28,7 +29,7 @@ use crate::BuildChunkingContextVc;
 pub(crate) struct EcmascriptBuildNodeEntryChunk {
     path: FileSystemPathVc,
     chunking_context: BuildChunkingContextVc,
-    other_chunks: AssetsVc,
+    other_chunks: OutputAssetsVc,
     evaluatable_assets: EvaluatableAssetsVc,
     exported_module: EcmascriptChunkPlaceableVc,
 }
@@ -40,7 +41,7 @@ impl EcmascriptBuildNodeEntryChunkVc {
     pub fn new(
         path: FileSystemPathVc,
         chunking_context: BuildChunkingContextVc,
-        other_chunks: AssetsVc,
+        other_chunks: OutputAssetsVc,
         evaluatable_assets: EvaluatableAssetsVc,
         exported_module: EcmascriptChunkPlaceableVc,
     ) -> Self {
@@ -181,6 +182,9 @@ fn chunk_reference_description() -> StringVc {
     StringVc::cell("chunk".to_string())
 }
 
+#[turbo_tasks::value_impl]
+impl OutputAsset for EcmascriptBuildNodeEntryChunk {}
+
 #[turbo_tasks::value_impl]
 impl Asset for EcmascriptBuildNodeEntryChunk {
     #[turbo_tasks::function]
@@ -202,9 +206,10 @@ impl Asset for EcmascriptBuildNodeEntryChunk {
         }
 
         let other_chunks = this.other_chunks.await?;
-        for other_chunk in &*other_chunks {
+        for &other_chunk in &*other_chunks {
             references.push(
-                SingleAssetReferenceVc::new(*other_chunk, chunk_reference_description()).into(),
+                SingleAssetReferenceVc::new(other_chunk.into(), chunk_reference_description())
+                    .into(),
             );
         }
 

crates/turbopack-build/src/ecmascript/node/entry/runtime.rs

@@ -9,6 +9,7 @@ use turbopack_core::{
     chunk::ChunkingContext,
     code_builder::{CodeBuilder, CodeVc},
     ident::AssetIdentVc,
+    output::{OutputAsset, OutputAssetVc},
     reference::{AssetReference, AssetReferenceVc, AssetReferencesVc},
     resolve::{ResolveResult, ResolveResultVc},
     source_map::{
@@ -88,6 +89,9 @@ impl ValueToString for EcmascriptBuildNodeRuntimeChunk {
     }
 }
 
+#[turbo_tasks::value_impl]
+impl OutputAsset for EcmascriptBuildNodeRuntimeChunk {}
+
 #[turbo_tasks::value_impl]
 impl Asset for EcmascriptBuildNodeRuntimeChunk {
     #[turbo_tasks::function]

crates/turbopack-core/src/chunk/chunking_context.rs

@@ -6,9 +6,7 @@ use turbo_tasks_fs::FileSystemPathVc;
 
 use super::{ChunkVc, EvaluatableAssetsVc};
 use crate::{
-    asset::{AssetVc, AssetsVc},
-    environment::EnvironmentVc,
-    ident::AssetIdentVc,
+    asset::AssetVc, environment::EnvironmentVc, ident::AssetIdentVc, output::OutputAssetsVc,
 };
 
 /// A context for the chunking that influences the way chunks are created
@@ -49,11 +47,11 @@ pub trait ChunkingContext {
 
     fn with_layer(&self, layer: &str) -> ChunkingContextVc;
 
-    fn chunk_group(&self, entry: ChunkVc) -> AssetsVc;
+    fn chunk_group(&self, entry: ChunkVc) -> OutputAssetsVc;
 
     fn evaluated_chunk_group(
         &self,
         entry: ChunkVc,
         evaluatable_assets: EvaluatableAssetsVc,
-    ) -> AssetsVc;
+    ) -> OutputAssetsVc;
 }

crates/turbopack-core/src/chunk/data.rs

@@ -3,8 +3,9 @@ use turbo_tasks::{primitives::StringVc, TryJoinIterExt};
 use turbo_tasks_fs::FileSystemPathVc;
 
 use crate::{
-    asset::{Asset, AssetVc, AssetsVc},
+    asset::Asset,
     chunk::{ModuleIdReadRef, OutputChunk, OutputChunkRuntimeInfo, OutputChunkVc},
+    output::{OutputAssetVc, OutputAssetsVc},
     reference::{AssetReferencesVc, SingleAssetReferenceVc},
 };
 
@@ -37,7 +38,7 @@ impl ChunkDataVc {
     #[turbo_tasks::function]
     pub async fn from_asset(
         output_root: FileSystemPathVc,
-        chunk: AssetVc,
+        chunk: OutputAssetVc,
     ) -> Result<ChunkDataOptionVc> {
         let output_root = output_root.await?;
         let path = chunk.ident().path().await?;
@@ -127,7 +128,7 @@ impl ChunkDataVc {
     #[turbo_tasks::function]
     pub async fn from_assets(
         output_root: FileSystemPathVc,
-        chunks: AssetsVc,
+        chunks: OutputAssetsVc,
     ) -> Result<ChunksDataVc> {
         Ok(ChunksDataVc::cell(
             chunks

crates/turbopack-core/src/chunk/mod.rs

@@ -39,6 +39,7 @@ use crate::{
     asset::{Asset, AssetVc, AssetsVc},
     ident::AssetIdentVc,
     module::{Module, ModuleVc},
+    output::OutputAssetsVc,
     reference::{AssetReference, AssetReferenceVc, AssetReferencesVc},
     resolve::{PrimaryResolveResult, ResolveResult, ResolveResultVc},
 };
@@ -208,7 +209,7 @@ impl ChunkGroupReferenceVc {
     }
 
     #[turbo_tasks::function]
-    async fn chunks(self) -> Result<AssetsVc> {
+    async fn chunks(self) -> Result<OutputAssetsVc> {
         let this = self.await?;
         Ok(this.chunking_context.chunk_group(this.entry))
     }
@@ -218,7 +219,7 @@ impl ChunkGroupReferenceVc {
 impl AssetReference for ChunkGroupReference {
     #[turbo_tasks::function]
     async fn resolve_reference(self_vc: ChunkGroupReferenceVc) -> Result<ResolveResultVc> {
-        let set = self_vc.chunks().await?.clone_value();
+        let set = self_vc.chunks().await?.iter().map(|&c| c.into()).collect();
         Ok(ResolveResult::assets(set).into())
     }
 }

crates/turbopack-core/src/lib.rs

@@ -18,9 +18,11 @@ pub mod ident;
 pub mod introspect;
 pub mod issue;
 pub mod module;
+pub mod output;
 pub mod package_json;
 pub mod proxied_asset;
 pub mod raw_module;
+pub mod raw_output;
 pub mod reference;
 pub mod reference_type;
 pub mod resolve;

crates/turbopack-core/src/output.rs

@@ -0,0 +1,29 @@
+use anyhow::{Context, Result};
+
+use crate::asset::{Asset, AssetVc};
+
+/// An asset that should be outputted, e. g. written to disk or served from a
+/// server.
+#[turbo_tasks::value_trait]
+pub trait OutputAsset: Asset {}
+
+#[turbo_tasks::value(transparent)]
+pub struct OutputAssets(Vec<OutputAssetVc>);
+
+#[turbo_tasks::value_impl]
+impl OutputAssetsVc {
+    #[turbo_tasks::function]
+    pub fn empty() -> Self {
+        Self::cell(Vec::new())
+    }
+}
+
+/// This is a temporary function that should be removed once the [OutputAsset]
+/// trait completely replaces the [Asset] trait.
+/// TODO make this function unnecessary
+#[turbo_tasks::function]
+pub async fn asset_to_output_asset(asset: AssetVc) -> Result<OutputAssetVc> {
+    OutputAssetVc::resolve_from(asset)
+        .await?
+        .context("Asset must be a OutputAsset")
+}

crates/turbopack-core/src/proxied_asset.rs

@@ -4,6 +4,7 @@ use turbo_tasks_fs::FileSystemPathVc;
 use crate::{
     asset::{Asset, AssetContentVc, AssetVc},
     ident::AssetIdentVc,
+    output::{OutputAsset, OutputAssetVc},
     reference::AssetReferencesVc,
     version::VersionedContentVc,
 };
@@ -27,6 +28,9 @@ impl ProxiedAssetVc {
     }
 }
 
+#[turbo_tasks::value_impl]
+impl OutputAsset for ProxiedAsset {}
+
 #[turbo_tasks::value_impl]
 impl Asset for ProxiedAsset {
     #[turbo_tasks::function]

crates/turbopack-core/src/raw_output.rs

@@ -0,0 +1,37 @@
+use crate::{
+    asset::{Asset, AssetContentVc, AssetVc},
+    ident::AssetIdentVc,
+    output::{OutputAsset, OutputAssetVc},
+    source::SourceVc,
+};
+
+/// A module where source code doesn't need to be parsed but can be used as is.
+/// This module has no references to other modules.
+#[turbo_tasks::value]
+pub struct RawOutput {
+    source: SourceVc,
+}
+
+#[turbo_tasks::value_impl]
+impl OutputAsset for RawOutput {}
+
+#[turbo_tasks::value_impl]
+impl Asset for RawOutput {
+    #[turbo_tasks::function]
+    fn ident(&self) -> AssetIdentVc {
+        self.source.ident()
+    }
+
+    #[turbo_tasks::function]
+    fn content(&self) -> AssetContentVc {
+        self.source.content()
+    }
+}
+
+#[turbo_tasks::value_impl]
+impl RawOutputVc {
+    #[turbo_tasks::function]
+    pub fn new(source: SourceVc) -> RawOutputVc {
+        RawOutput { source }.cell()
+    }
+}

crates/turbopack-core/src/source_map/source_map_asset.rs

@@ -7,6 +7,7 @@ use crate::{
     asset::{Asset, AssetContentVc, AssetVc},
     ident::AssetIdentVc,
     introspect::{Introspectable, IntrospectableChildrenVc, IntrospectableVc},
+    output::{OutputAsset, OutputAssetVc},
     reference::{AssetReference, AssetReferenceVc},
     resolve::{ResolveResult, ResolveResultVc},
     source_map::{GenerateSourceMap, GenerateSourceMapVc, SourceMapVc},
@@ -26,6 +27,9 @@ impl SourceMapAssetVc {
     }
 }
 
+#[turbo_tasks::value_impl]
+impl OutputAsset for SourceMapAsset {}
+
 #[turbo_tasks::value_impl]
 impl Asset for SourceMapAsset {
     #[turbo_tasks::function]