Avoid negative configuration naming

Author: bgw

crates/next-core/src/next_config.rs

@@ -870,11 +870,11 @@ pub struct ExperimentalConfig {
     turbopack_use_system_tls_certs: Option<bool>,
     /// Disable automatic configuration of the sass loader.
     #[serde(default)]
-    turbopack_disable_builtin_sass: Option<bool>,
+    turbopack_use_builtin_sass: Option<bool>,
     /// Disable automatic configuration of the babel loader when a babel configuration file is
     /// present.
     #[serde(default)]
-    turbopack_disable_builtin_babel: Option<bool>,
+    turbopack_use_builtin_babel: Option<bool>,
     // Whether to enable the global-not-found convention
     global_not_found: Option<bool>,
     /// Defaults to false in development mode, true in production mode.
@@ -1646,13 +1646,13 @@ impl NextConfig {
     }
 
     #[turbo_tasks::function]
-    pub fn experimental_turbopack_disable_builtin_babel(&self) -> Vc<Option<bool>> {
-        Vc::cell(self.experimental.turbopack_disable_builtin_babel)
+    pub fn experimental_turbopack_use_builtin_babel(&self) -> Vc<Option<bool>> {
+        Vc::cell(self.experimental.turbopack_use_builtin_babel)
     }
 
     #[turbo_tasks::function]
-    pub fn experimental_turbopack_disable_builtin_sass(&self) -> Vc<Option<bool>> {
-        Vc::cell(self.experimental.turbopack_disable_builtin_sass)
+    pub fn experimental_turbopack_use_builtin_sass(&self) -> Vc<Option<bool>> {
+        Vc::cell(self.experimental.turbopack_use_builtin_sass)
     }
 
     #[turbo_tasks::function]

crates/next-core/src/next_shared/webpack_rules/mod.rs

@@ -155,17 +155,17 @@ pub async fn webpack_loader_options(
 
     let config_file_path = async || project_path.join(&next_config.await?.config_file_name);
 
-    let disable_builtin_sass = next_config
-        .experimental_turbopack_disable_builtin_sass()
+    let use_builtin_sass = next_config
+        .experimental_turbopack_use_builtin_sass()
         .await?;
-    if !disable_builtin_sass.unwrap_or(false) {
-        if disable_builtin_sass.is_none()
+    if use_builtin_sass.unwrap_or(true) {
+        if use_builtin_sass.is_none()
             && let Some(glob) = detect_likely_sass_loader(&rules).await?
         {
             ManuallyConfiguredBuiltinLoaderIssue {
                 glob,
                 loader: rcstr!("sass-loader"),
-                disable_builtin_config_key: rcstr!("experimental.turbopackDisableBuiltinSass"),
+                config_key: rcstr!("experimental.turbopackUseBuiltinSass"),
                 config_file_path: config_file_path().await?,
             }
             .resolved_cell()
@@ -178,13 +178,13 @@ pub async fn webpack_loader_options(
     // (https://github.com/vercel/next.js/pull/82676) and the react-compiler logic is moved into
     // here. React-compiler is currently configured in JS before it gets to us, which could trigger
     // false-positives.
-    let disable_builtin_babel = next_config
-        .experimental_turbopack_disable_builtin_babel()
+    let use_builtin_babel = next_config
+        .experimental_turbopack_use_builtin_babel()
         .await?;
     if !builtin_conditions.contains(&WebpackLoaderBuiltinCondition::Foreign)
-        && !disable_builtin_babel.unwrap_or(false)
+        && use_builtin_babel.unwrap_or(true)
     {
-        if disable_builtin_babel.is_none()
+        if use_builtin_babel.is_none()
             && let Some(glob) = detect_likely_babel_loader(&rules).await?
         {
             let _ = glob;
@@ -196,7 +196,7 @@ pub async fn webpack_loader_options(
             ManuallyConfiguredBuiltinLoaderIssue {
                 glob,
                 loader: rcstr!("babel-loader"),
-                disable_builtin_config_key: rcstr!("experimental.turbopackDisableBuiltinBabel"),
+                disable_builtin_config_key: rcstr!("experimental.turbopackUseBuiltinBabel"),
                 config_file_path: config_file_path().await?,
             }
             .resolved_cell()
@@ -241,7 +241,7 @@ fn loader_runner_package_mapping() -> Result<Vc<ImportMapping>> {
 struct ManuallyConfiguredBuiltinLoaderIssue {
     glob: RcStr,
     loader: RcStr,
-    disable_builtin_config_key: RcStr,
+    config_key: RcStr,
     config_file_path: FileSystemPath,
 }
 
@@ -282,13 +282,14 @@ impl Issue for ManuallyConfiguredBuiltinLoaderIssue {
                 )),
                 StyledString::Line(vec![
                     StyledString::Text(rcstr!("You can silence this warning by setting ")),
-                    StyledString::Code(self.disable_builtin_config_key.clone()),
+                    StyledString::Code(self.config_key.clone()),
                     StyledString::Text(rcstr!(" in ")),
                     StyledString::Text(self.config_file_path.path.clone()),
                     StyledString::Text(rcstr!(" to ")),
                     StyledString::Code(rcstr!("true")),
-                    StyledString::Text(rcstr!(" or ")),
+                    StyledString::Text(rcstr!(" (to silence this warning) or ")),
                     StyledString::Code(rcstr!("false")),
+                    StyledString::Text(rcstr!(" (to disable the default built-in loader)")),
                 ]),
             ])
             .resolved_cell(),

packages/next/src/server/config-schema.ts

@@ -480,8 +480,8 @@ export const configSchema: zod.ZodType<NextConfig> = z.lazy(() =>
         turbopackRemoveUnusedExports: z.boolean().optional(),
         turbopackScopeHoisting: z.boolean().optional(),
         turbopackUseSystemTlsCerts: z.boolean().optional(),
-        turbopackDisableBuiltinBabel: z.boolean().optional(),
-        turbopackDisableBuiltinSass: z.boolean().optional(),
+        turbopackUseBuiltinBabel: z.boolean().optional(),
+        turbopackUseBuiltinSass: z.boolean().optional(),
         optimizePackageImports: z.array(z.string()).optional(),
         optimizeServerReact: z.boolean().optional(),
         clientTraceMetadata: z.array(z.string()).optional(),

packages/next/src/server/config-shared.ts

@@ -638,15 +638,16 @@ export interface ExperimentalConfig {
   turbopackUseSystemTlsCerts?: boolean
 
   /**
-   * Disable automatic configuration of the babel loader when a babel configuration file is
-   * present.
+   * Set this to `false` to disable the automatic configuration of the babel loader when a babel
+   * configuration file is present. The babel loader configuration is enabled by default.
    */
-  turbopackDisableBuiltinBabel?: boolean
+  turbopackUseBuiltinBabel?: boolean
 
   /**
-   * Disable automatic configuration of the sass loader.
+   * Set this to `false` to disable the automatic configuration of the sass loader. The sass loader
+   * configuration is enabled by default.
    */
-  turbopackDisableBuiltinSass?: boolean
+  turbopackUseBuiltinSass?: boolean
 
   /**
    * For use with `@next/mdx`. Compile MDX files using the new Rust compiler.