Allow overriding outputHashSalt in modifyConfig (#92856)

Author: mischnic

crates/next-api/src/project.rs

@@ -370,11 +370,6 @@ pub struct ProjectOptions {
 
     /// Whether server-side HMR is enabled (disabled with --no-server-fast-refresh).
     pub server_hmr: bool,
-
-    /// A salt to mix into chunk and asset content hashes, allowing users to
-    /// force new filenames without changing file content. Empty string means
-    /// no salt.
-    pub hash_salt: RcStr,
 }
 
 #[derive(Default)]
@@ -425,9 +420,6 @@ pub struct PartialProjectOptions {
     /// Debug build paths for selective builds.
     /// When set, only routes matching these paths will be included in the build.
     pub debug_build_paths: Option<DebugBuildPaths>,
-
-    /// An optional salt to mix into chunk and asset content hashes.
-    pub hash_salt: Option<RcStr>,
 }
 
 #[derive(
@@ -687,7 +679,6 @@ impl ProjectContainer {
                 no_mangling,
                 write_routes_hashes_manifest,
                 debug_build_paths,
-                hash_salt,
             } = options;
 
             let mut new_options = this
@@ -738,9 +729,6 @@ impl ProjectContainer {
             if let Some(debug_build_paths) = debug_build_paths {
                 new_options.debug_build_paths = Some(debug_build_paths);
             }
-            if let Some(hash_salt) = hash_salt {
-                new_options.hash_salt = hash_salt;
-            }
 
             // TODO: Handle mode switch, should prevent mode being switched.
             let watch = new_options.watch;
@@ -823,7 +811,6 @@ impl ProjectContainer {
         let deferred_entries;
         let is_persistent_caching_enabled;
         let server_hmr;
-        let hash_salt;
         {
             let options = self.options_state.get();
             let options = options
@@ -852,7 +839,6 @@ impl ProjectContainer {
             deferred_entries = options.deferred_entries.clone().unwrap_or_default();
             is_persistent_caching_enabled = options.is_persistent_caching_enabled;
             server_hmr = options.server_hmr;
-            hash_salt = options.hash_salt.clone();
         }
 
         let root_path = ResolvedVc::cell(root_path_str);
@@ -884,7 +870,6 @@ impl ProjectContainer {
             deferred_entries,
             is_persistent_caching_enabled,
             server_hmr,
-            hash_salt,
         }
         .cell())
     }
@@ -988,10 +973,6 @@ pub struct Project {
 
     /// Whether server-side HMR is enabled (disabled with --no-server-fast-refresh).
     server_hmr: bool,
-
-    /// A salt to mix into chunk and asset content hashes. Empty string means
-    /// no salt.
-    hash_salt: RcStr,
 }
 
 #[turbo_tasks::value]
@@ -1249,11 +1230,6 @@ impl Project {
         Vc::cell(self.no_mangling)
     }
 
-    #[turbo_tasks::function]
-    pub(crate) fn hash_salt(&self) -> Vc<RcStr> {
-        Vc::cell(self.hash_salt.clone())
-    }
-
     #[turbo_tasks::function]
     pub(super) async fn execution_context(self: Vc<Self>) -> Result<Vc<ExecutionContext>> {
         let node_root = self.node_root().owned().await?;
@@ -1609,7 +1585,7 @@ impl Project {
             debug_ids: self.next_config().turbopack_debug_ids(),
             should_use_absolute_url_references: self.next_config().inline_css(),
             css_url_suffix,
-            hash_salt: self.hash_salt().to_resolved().await?,
+            hash_salt: self.next_config().output_hash_salt().to_resolved().await?,
             cross_origin: self.next_config().cross_origin(),
         }))
     }
@@ -1645,7 +1621,7 @@ impl Project {
                 .await?,
             asset_prefix: self.next_config().computed_asset_prefix().owned().await?,
             css_url_suffix,
-            hash_salt: self.hash_salt().to_resolved().await?,
+            hash_salt: self.next_config().output_hash_salt().to_resolved().await?,
         };
         Ok(if client_assets {
             get_server_chunking_context_with_client_assets(options)
@@ -1684,7 +1660,7 @@ impl Project {
                 .await?,
             asset_prefix: self.next_config().computed_asset_prefix().owned().await?,
             css_url_suffix,
-            hash_salt: self.hash_salt().to_resolved().await?,
+            hash_salt: self.next_config().output_hash_salt().to_resolved().await?,
             cross_origin: self.next_config().cross_origin(),
         };
         Ok(if client_assets {

crates/next-api/src/project_asset_hashes_manifest.rs

@@ -143,7 +143,10 @@ impl Asset for AssetHashesManifestAsset {
                 Ok((
                     path,
                     asset
-                        .content_hash(self.project.hash_salt(), HashAlgorithm::Xxh3Hash128Base38)
+                        .content_hash(
+                            self.project.next_config().output_hash_salt(),
+                            HashAlgorithm::Xxh3Hash128Base38,
+                        )
                         .await?,
                 ))
             })

crates/next-build-test/src/main.rs

@@ -190,7 +190,6 @@ fn main() {
                 is_persistent_caching_enabled: false,
                 next_version: rcstr!("0.0.0"),
                 server_hmr: false,
-                hash_salt: rcstr!(""),
             };
 
             let json = serde_json::to_string_pretty(&options).unwrap();

crates/next-core/src/next_config.rs

@@ -1090,6 +1090,10 @@ pub struct ExperimentalConfig {
     runtime_server_deployment_id: Option<bool>,
     supports_immutable_assets: Option<bool>,
 
+    /// A salt to mix into chunk and asset content hashes. Empty string means
+    /// no salt.
+    output_hash_salt: Option<RcStr>,
+
     // ---
     // UNSUPPORTED
     // ---
@@ -2349,6 +2353,16 @@ impl NextConfig {
             .collect::<Result<Vec<_>>>()?;
         Ok(Vc::cell(rules))
     }
+
+    #[turbo_tasks::function]
+    pub fn output_hash_salt(&self) -> Vc<RcStr> {
+        Vc::cell(
+            self.experimental
+                .output_hash_salt
+                .clone()
+                .unwrap_or_default(),
+        )
+    }
 }
 
 /// A subset of ts/jsconfig that next.js implicitly

crates/next-napi-bindings/src/next_api/project.rs

@@ -216,11 +216,6 @@ pub struct NapiProjectOptions {
 
     /// Whether server-side HMR is enabled (disabled with --no-server-fast-refresh).
     pub server_hmr: Option<bool>,
-
-    /// A salt to mix into chunk and asset content hashes, allowing users to
-    /// force new filenames without changing file content. Empty string means
-    /// no salt.
-    pub hash_salt: RcStr,
 }
 
 /// [NapiProjectOptions] with all fields optional.
@@ -271,9 +266,6 @@ pub struct NapiPartialProjectOptions {
     /// local names for variables, functions etc., which can be useful for
     /// debugging/profiling purposes.
     pub no_mangling: Option<bool>,
-
-    /// An optional salt to mix into chunk and asset content hashes.
-    pub hash_salt: Option<RcStr>,
 }
 
 #[napi(object)]
@@ -334,7 +326,6 @@ impl From<NapiProjectOptions> for ProjectOptions {
             is_persistent_caching_enabled,
             next_version,
             server_hmr,
-            hash_salt,
         } = val;
         ProjectOptions {
             root_path,
@@ -359,7 +350,6 @@ impl From<NapiProjectOptions> for ProjectOptions {
             is_persistent_caching_enabled,
             next_version,
             server_hmr: server_hmr.unwrap_or(false),
-            hash_salt,
         }
     }
 }
@@ -380,7 +370,6 @@ impl From<NapiPartialProjectOptions> for PartialProjectOptions {
             browserslist_query,
             no_mangling,
             write_routes_hashes_manifest,
-            hash_salt,
         } = val;
         PartialProjectOptions {
             root_path,
@@ -397,7 +386,6 @@ impl From<NapiPartialProjectOptions> for PartialProjectOptions {
             no_mangling,
             write_routes_hashes_manifest,
             debug_build_paths: None,
-            hash_salt,
         }
     }
 }

packages/next/src/build/swc/generated-native.d.ts

@@ -258,12 +258,6 @@ export interface NapiProjectOptions {
   nextVersion: RcStr
   /** Whether server-side HMR is enabled (disabled with --no-server-fast-refresh). */
   serverHmr?: boolean
-  /**
-   * A salt to mix into chunk and asset content hashes, allowing users to
-   * force new filenames without changing file content. Empty string means
-   * no salt.
-   */
-  hashSalt: RcStr
 }
 /** [NapiProjectOptions] with all fields optional. */
 export interface NapiPartialProjectOptions {
@@ -308,8 +302,6 @@ export interface NapiPartialProjectOptions {
    * debugging/profiling purposes.
    */
   noMangling?: boolean
-  /** An optional salt to mix into chunk and asset content hashes. */
-  hashSalt?: RcStr
 }
 export interface NapiDefineEnv {
   client: Array<NapiOptionEnvVar>

packages/next/src/build/turbopack-analyze/index.ts

@@ -91,7 +91,6 @@ export async function turbopackAnalyze(
       currentNodeJsVersion,
       isPersistentCachingEnabled: persistentCaching,
       nextVersion: process.env.__NEXT_VERSION as string,
-      hashSalt: config.hashSalt,
     },
     {
       memoryLimit: config.experimental?.turbopackMemoryLimit,

packages/next/src/build/turbopack-build/impl.ts

@@ -114,7 +114,6 @@ export async function turbopackBuild(): Promise<{
     isPersistentCachingEnabled: persistentCaching,
     deferredEntries: config.experimental.deferredEntries,
     nextVersion: process.env.__NEXT_VERSION as string,
-    hashSalt: config.hashSalt,
   }
 
   const sharedTurboOptions = {

packages/next/src/build/webpack-config.ts

@@ -1347,7 +1347,9 @@ export default async function getBaseWebpackConfig(
       hashDigestLength: 16,
       // Webpack requires hashSalt to be a non-empty string; omit it entirely
       // when no salt is configured.
-      ...(config.hashSalt ? { hashSalt: config.hashSalt } : {}),
+      ...(config.experimental?.outputHashSalt
+        ? { hashSalt: config.experimental.outputHashSalt }
+        : {}),
     },
     performance: false,
     resolve: resolveConfig,
@@ -1799,7 +1801,7 @@ export default async function getBaseWebpackConfig(
                   compilerType,
                   basePath: config.basePath,
                   assetPrefix: config.assetPrefix,
-                  hashSalt: config.hashSalt,
+                  outputHashSalt: config.experimental?.outputHashSalt,
                 },
               },
             ]

packages/next/src/build/webpack/loaders/next-image-loader/index.ts

@@ -10,21 +10,22 @@ interface Options {
   isDev: boolean
   assetPrefix: string
   basePath: string
-  hashSalt: string
+  outputHashSalt: string
 }
 
 function nextImageLoader(this: any, content: Buffer) {
   const imageLoaderSpan = this.currentTraceSpan.traceChild('next-image-loader')
   return imageLoaderSpan.traceAsyncFn(async () => {
     const options: Options = this.getOptions()
-    const { compilerType, isDev, assetPrefix, basePath, hashSalt } = options
+    const { compilerType, isDev, assetPrefix, basePath, outputHashSalt } =
+      options
     const context = this.rootContext
 
     // Prepend the hash salt to the content for filename hash computation, so
     // that NEXT_HASH_SALT causes image filenames to change (like it does for
     // chunks). The actual file content is unaffected.
-    const contentForHash = hashSalt
-      ? Buffer.concat([Buffer.from(hashSalt, 'utf8'), content])
+    const contentForHash = outputHashSalt
+      ? Buffer.concat([Buffer.from(outputHashSalt, 'utf8'), content])
       : content
     const opts = { context, content: contentForHash }
     const interpolatedName = loaderUtils.interpolateName(