make base path optional

When you don't provide a `base` path, we disable auto content detection.
This is currently only done in the `@tailwindcss/vite` package.

Note: you can't enable/disable auto content detection from user land
yet. That will be a separate PR.

crates/node/src/lib.rs

@@ -26,7 +26,7 @@ impl From<ChangedContent> for tailwindcss_oxide::ChangedContent {
 pub struct ScanResult {
   // Private information necessary for incremental rebuilds. Note: these fields are not exposed
   // to JS
-  base: String,
+  base: Option<String>,
   sources: Vec<GlobEntry>,
 
   // Public API:
@@ -77,7 +77,7 @@ impl From<tailwindcss_oxide::GlobEntry> for GlobEntry {
 #[napi(object)]
 pub struct ScanOptions {
   /// Base path to start scanning from
-  pub base: String,
+  pub base: Option<String>,
   /// Glob sources
   pub sources: Option<Vec<GlobEntry>>,
 }

crates/oxide/src/lib.rs

@@ -42,7 +42,7 @@ pub struct ChangedContent {
 #[derive(Debug, Clone)]
 pub struct ScanOptions {
     /// Base path to start scanning from
-    pub base: String,
+    pub base: Option<String>,
     /// Glob sources
     pub sources: Vec<GlobEntry>,
 }
@@ -68,11 +68,17 @@ pub fn clear_cache() {
 pub fn scan_dir(opts: ScanOptions) -> ScanResult {
     init_tracing();
 
-    let base = Path::new(&opts.base);
-
-    let (mut files, dirs) = resolve_files(base);
+    let (mut files, mut globs) = match opts.base {
+        Some(base) => {
+            // Only enable auto content detection when `base` is provided.
+            let base = Path::new(&base);
+            let (files, dirs) = resolve_files(base);
+            let globs = resolve_globs(base, dirs);
 
-    let mut globs = resolve_globs(base, dirs);
+            (files, globs)
+        }
+        None => (vec![], vec![]),
+    };
 
     // If we have additional sources, then we have to resolve them as well.
     if !opts.sources.is_empty() {

crates/oxide/tests/scan_dir.rs

@@ -39,7 +39,7 @@ mod scan_dir {
 
         // Resolve all content paths for the (temporary) current working directory
         let result = scan_dir(ScanOptions {
-            base: base.clone(),
+            base: Some(base.clone()),
             sources: globs
                 .iter()
                 .map(|x| GlobEntry {

packages/@tailwindcss-vite/src/index.ts

@@ -88,9 +88,6 @@ export default function tailwindcss(): Plugin[] {
     })
 
     scanDirResult = scanDir({
-      // TODO: This might not be necessary if we enable/disabled auto content
-      // detection.
-      base: config!.root, // Root directory, mainly used for auto content detection
       sources: globs.map((pattern) => ({
         base: inputBasePath, // Globs are relative to the input.css file
         pattern,