fix: ignore non-string safelist entries instead of crashing the build

A Tailwind-style { pattern: /.../ } safelist entry reached parseClass
and threw 'className.startsWith is not a function', killing the whole
build. Non-string entries are now skipped with a warning (build) or
silently (plugin); pattern expansion remains unsupported.

Author: chrisbbreuer

packages/crosswind/src/build.ts

@@ -33,9 +33,16 @@ export async function build(config: CrosswindConfig): Promise<BuildResult> {
   })
   const { classes, transformedFiles } = await scanner.scan()
 
-  // Add safelist classes
+  // Add safelist classes. Only strings are supported — a Tailwind-style
+  // { pattern: /.../ } entry previously reached parseClass and crashed the
+  // whole build with 'className.startsWith is not a function'.
   for (const cls of config.safelist) {
-    classes.add(cls)
+    if (typeof cls === 'string') {
+      classes.add(cls)
+    }
+    else {
+      console.warn(`⚠️  Ignoring non-string safelist entry (patterns are not supported): ${JSON.stringify(cls)}`)
+    }
   }
 
   // Generate CSS

packages/crosswind/src/plugin.ts

@@ -105,9 +105,11 @@ export function plugin(options: CrosswindPluginOptions = {}): BunPlugin {
           bracketSyntax: config.bracketSyntax,
         })
 
-        // Add safelist classes
+        // Add safelist classes (strings only; pattern objects are ignored)
         for (const cls of config.safelist) {
-          classes.add(cls)
+          if (typeof cls === 'string') {
+            classes.add(cls)
+          }
         }
 
         // Generate CSS

packages/crosswind/test/build.test.ts

@@ -20,6 +20,17 @@ describe('build', () => {
     await rm(TEST_DIR, { recursive: true, force: true })
   })
 
+  it('ignores non-string safelist entries instead of crashing', async () => {
+    const config = {
+      ...defaultConfig,
+      content: [join(TEST_DIR, '*.html')],
+      minify: false,
+      safelist: ['bg-red-500', { pattern: /bg-(green|blue)-500/ } as any],
+    }
+    const result = await build(config)
+    expect(result.css).toContain('.bg-red-500')
+  })
+
   it('should build CSS from files', async () => {
     const config = {
       ...defaultConfig,