Scan Next.js dynamic route segments with manual @source rules (#16457)

Part of #16287

## Test plan

Added unit and integration tests

---------

Co-authored-by: Robin Malfait <malfait.robin@gmail.com>

CHANGELOG.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Ensure drop shadow utilities don't inherit unexpectedly ([#16471](https://github.com/tailwindlabs/tailwindcss/pull/16471))
 - Export backwards compatible config and plugin types from `tailwindcss/plugin` ([#16505](https://github.com/tailwindlabs/tailwindcss/pull/16505))
 - Ensure JavaScript plugins that emit nested rules referencing to the utility name work as expected ([#16539](https://github.com/tailwindlabs/tailwindcss/pull/16539))
+- Ensure that Next.js splat routes are automatically scanned for classes ([#16457](https://github.com/tailwindlabs/tailwindcss/pull/16457))
 - Pin exact versions of `tailwindcss` and `@tailwindcss/*` ([#16623](https://github.com/tailwindlabs/tailwindcss/pull/16623))
 - Upgrade: Report errors when updating dependencies ([#16504](https://github.com/tailwindlabs/tailwindcss/pull/16504))
 - Upgrade: Ensure a `darkMode` JS config setting with block syntax converts to use `@slot` ([#16507](https://github.com/tailwindlabs/tailwindcss/pull/16507))

Cargo.lock

@@ -11,6 +11,12 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "arrayvec"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c02d123df017efcdfbd739ef81735b36c5ba83ec3c59c80a9d7ecc718f92e50"
+
 [[package]]
 name = "bexpand"
 version = "1.2.0"
@@ -141,18 +147,21 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "fast-glob"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0eca69ef247d19faa15ac0156968637440824e5ff22baa5ee0cd35b2f7ea6a0f"
+dependencies = [
+ "arrayvec",
+]
+
 [[package]]
 name = "fastrand"
 version = "2.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e8c02a5121d4ea3eb16a80748c74f5549a5665e4c21333c6098f283870fbdea6"
 
-[[package]]
-name = "glob-match"
-version = "0.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9985c9503b412198aa4197559e9a318524ebc4519c229bfa05a535828c950b9d"
-
 [[package]]
 name = "globset"
 version = "0.4.15"
@@ -524,7 +533,7 @@ dependencies = [
  "bstr",
  "crossbeam",
  "dunce",
- "glob-match",
+ "fast-glob",
  "globwalk",
  "ignore",
  "log",

crates/oxide/Cargo.toml

@@ -16,7 +16,7 @@ walkdir = "2.5.0"
 ignore = "0.4.23"
 dunce = "1.0.5"
 bexpand = "1.2.0"
-glob-match = "0.2.1"
+fast-glob = "0.4.3"
 
 [dev-dependencies]
 tempfile = "3.13.0"

crates/oxide/src/glob.rs

@@ -1,5 +1,5 @@
+use fast_glob::glob_match;
 use fxhash::{FxHashMap, FxHashSet};
-use glob_match::glob_match;
 use std::path::{Path, PathBuf};
 use tracing::event;
 
@@ -173,7 +173,7 @@ pub fn path_matches_globs(path: &Path, globs: &[GlobEntry]) -> bool {
 
     globs
         .iter()
-        .any(|g| glob_match(&format!("{}/{}", g.base, g.pattern), &path))
+        .any(|g| glob_match(&format!("{}/{}", g.base, g.pattern), path.as_bytes()))
 }
 
 #[cfg(test)]

crates/oxide/src/lib.rs

@@ -4,9 +4,9 @@ use crate::scanner::allowed_paths::resolve_paths;
 use crate::scanner::detect_sources::DetectSources;
 use bexpand::Expression;
 use bstr::ByteSlice;
+use fast_glob::glob_match;
 use fxhash::{FxHashMap, FxHashSet};
 use glob::optimize_patterns;
-use glob_match::glob_match;
 use paths::Path;
 use rayon::prelude::*;
 use scanner::allowed_paths::read_dir;

crates/oxide/tests/scanner.rs

@@ -415,6 +415,32 @@ mod scanner {
         assert_eq!(candidates, vec!["content-['foo.styl']"]);
     }
 
+    #[test]
+    fn it_should_scan_next_dynamic_folders() {
+        let candidates = scan_with_globs(
+            &[
+                // We know that `.styl` extensions are ignored, so they are not covered by auto content
+                // detection.
+                ("app/[slug]/page.styl", "content-['[slug]']"),
+                ("app/[...slug]/page.styl", "content-['[...slug]']"),
+                ("app/[[...slug]]/page.styl", "content-['[[...slug]]']"),
+                ("app/(theme)/page.styl", "content-['(theme)']"),
+            ],
+            vec!["./**/*.{styl}"],
+        )
+        .1;
+
+        assert_eq!(
+            candidates,
+            vec![
+                "content-['(theme)']",
+                "content-['[...slug]']",
+                "content-['[[...slug]]']",
+                "content-['[slug]']",
+            ],
+        );
+    }
+
     #[test]
     fn it_should_scan_absolute_paths() {
         // Create a temporary working directory

integrations/postcss/next.test.ts

@@ -162,3 +162,89 @@ describe.each(['turbo', 'webpack'])('%s', (bundler) => {
     },
   )
 })
+
+test(
+  'should scan dynamic route segments',
+  {
+    fs: {
+      'package.json': json`
+        {
+          "dependencies": {
+            "react": "^18",
+            "react-dom": "^18",
+            "next": "^14"
+          },
+          "devDependencies": {
+            "@tailwindcss/postcss": "workspace:^",
+            "tailwindcss": "workspace:^"
+          }
+        }
+      `,
+      'postcss.config.mjs': js`
+        /** @type {import('postcss-load-config').Config} */
+        const config = {
+          plugins: {
+            '@tailwindcss/postcss': {},
+          },
+        }
+
+        export default config
+      `,
+      'next.config.mjs': js`
+        /** @type {import('next').NextConfig} */
+        const nextConfig = {}
+
+        export default nextConfig
+      `,
+      'app/a/[slug]/page.js': js`
+        export default function Page() {
+          return <h1 className="content-['[slug]']">Hello, Next.js!</h1>
+        }
+      `,
+      'app/b/[...slug]/page.js': js`
+        export default function Page() {
+          return <h1 className="content-['[...slug]']">Hello, Next.js!</h1>
+        }
+      `,
+      'app/c/[[...slug]]/page.js': js`
+        export default function Page() {
+          return <h1 className="content-['[[...slug]]']">Hello, Next.js!</h1>
+        }
+      `,
+      'app/d/(theme)/page.js': js`
+        export default function Page() {
+          return <h1 className="content-['(theme)']">Hello, Next.js!</h1>
+        }
+      `,
+      'app/layout.js': js`
+        import './globals.css'
+
+        export default function RootLayout({ children }) {
+          return (
+            <html>
+              <body>{children}</body>
+            </html>
+          )
+        }
+      `,
+      'app/globals.css': css`
+        @import 'tailwindcss/utilities' source(none);
+        @source './**/*.{js,ts,jsx,tsx,mdx}';
+      `,
+    },
+  },
+  async ({ fs, exec, expect }) => {
+    await exec('pnpm next build')
+
+    let files = await fs.glob('.next/static/css/**/*.css')
+    expect(files).toHaveLength(1)
+    let [filename] = files[0]
+
+    await fs.expectFileToContain(filename, [
+      candidate`content-['[slug]']`,
+      candidate`content-['[...slug]']`,
+      candidate`content-['[[...slug]]']`,
+      candidate`content-['(theme)']`,
+    ])
+  },
+)