(1/n) shadcn: add tailwind version detection (#6478)

* feat(shadcn): add tailwind version detection

* chore: changeset

Author: shadcn

.changeset/five-hounds-tell.md

@@ -0,0 +1,5 @@
+---
+"shadcn": minor
+---
+
+add tailwind version detection

packages/shadcn/src/preflights/preflight-init.ts

@@ -81,7 +81,16 @@ export async function preFlightInit(
   const tailwindSpinner = spinner(`Validating Tailwind CSS.`, {
     silent: options.silent,
   }).start()
-  if (!projectInfo?.tailwindConfigFile || !projectInfo?.tailwindCssFile) {
+  if (
+    projectInfo.tailwindVersion === "v3" &&
+    (!projectInfo?.tailwindConfigFile || !projectInfo?.tailwindCssFile)
+  ) {
+    errors[ERRORS.TAILWIND_NOT_CONFIGURED] = true
+    tailwindSpinner?.fail()
+  } else if (
+    projectInfo.tailwindVersion === "v4" &&
+    !projectInfo?.tailwindCssFile
+  ) {
     errors[ERRORS.TAILWIND_NOT_CONFIGURED] = true
     tailwindSpinner?.fail()
   } else {

packages/shadcn/src/utils/get-config.ts

@@ -3,7 +3,6 @@ import { highlighter } from "@/src/utils/highlighter"
 import { resolveImport } from "@/src/utils/resolve-import"
 import { cosmiconfig } from "cosmiconfig"
 import fg from "fast-glob"
-import fs from "fs-extra"
 import { loadConfig } from "tsconfig-paths"
 import { z } from "zod"
 
@@ -27,7 +26,7 @@ export const rawConfigSchema = z
     rsc: z.coerce.boolean().default(false),
     tsx: z.coerce.boolean().default(true),
     tailwind: z.object({
-      config: z.string(),
+      config: z.string().optional(),
       css: z.string(),
       baseColor: z.string(),
       cssVariables: z.boolean().default(true),
@@ -96,7 +95,9 @@ export async function resolveConfigPaths(cwd: string, config: RawConfig) {
     ...config,
     resolvedPaths: {
       cwd,
-      tailwindConfig: path.resolve(cwd, config.tailwind.config),
+      tailwindConfig: config.tailwind.config
+        ? path.resolve(cwd, config.tailwind.config)
+        : "",
       tailwindCss: path.resolve(cwd, config.tailwind.css),
       utils: await resolveImport(config.aliases["utils"], tsConfig),
       components: await resolveImport(config.aliases["components"], tsConfig),

packages/shadcn/src/utils/get-project-info.ts

@@ -19,6 +19,7 @@ type ProjectInfo = {
   isTsx: boolean
   tailwindConfigFile: string | null
   tailwindCssFile: string | null
+  tailwindVersion: "v3" | "v4" | null
   aliasPrefix: string | null
 }
 
@@ -43,6 +44,7 @@ export async function getProjectInfo(cwd: string): Promise<ProjectInfo | null> {
     isTsx,
     tailwindConfigFile,
     tailwindCssFile,
+    tailwindVersion,
     aliasPrefix,
     packageJson,
   ] = await Promise.all([
@@ -55,6 +57,7 @@ export async function getProjectInfo(cwd: string): Promise<ProjectInfo | null> {
     isTypeScriptProject(cwd),
     getTailwindConfigFile(cwd),
     getTailwindCssFile(cwd),
+    getTailwindVersion(cwd),
     getTsConfigAliasPrefix(cwd),
     getPackageInfo(cwd, false),
   ])
@@ -70,6 +73,7 @@ export async function getProjectInfo(cwd: string): Promise<ProjectInfo | null> {
     isTsx,
     tailwindConfigFile,
     tailwindCssFile,
+    tailwindVersion,
     aliasPrefix,
   }
 
@@ -121,21 +125,50 @@ export async function getProjectInfo(cwd: string): Promise<ProjectInfo | null> {
   return type
 }
 
+export async function getTailwindVersion(
+  cwd: string
+): Promise<ProjectInfo["tailwindVersion"]> {
+  const packageInfo = getPackageInfo(cwd)
+
+  if (
+    !packageInfo?.dependencies?.tailwindcss &&
+    !packageInfo?.devDependencies?.tailwindcss
+  ) {
+    return null
+  }
+
+  if (
+    /^(?:\^|~)?3(?:\.\d+)*(?:-.*)?$/.test(
+      packageInfo?.dependencies?.tailwindcss ||
+        packageInfo?.devDependencies?.tailwindcss ||
+        ""
+    )
+  ) {
+    return "v3"
+  }
+
+  return "v4"
+}
+
 export async function getTailwindCssFile(cwd: string) {
-  const files = await fg.glob(["**/*.css", "**/*.scss"], {
-    cwd,
-    deep: 5,
-    ignore: PROJECT_SHARED_IGNORE,
-  })
+  const [files, tailwindVersion] = await Promise.all([
+    fg.glob(["**/*.css", "**/*.scss"], {
+      cwd,
+      deep: 5,
+      ignore: PROJECT_SHARED_IGNORE,
+    }),
+    getTailwindVersion(cwd),
+  ])
 
   if (!files.length) {
     return null
   }
 
+  const needle =
+    tailwindVersion === "v4" ? `@import "tailwindcss"` : "@tailwind base"
   for (const file of files) {
     const contents = await fs.readFile(path.resolve(cwd, file), "utf8")
-    // Assume that if the file contains `@tailwind base` it's the main css file.
-    if (contents.includes("@tailwind base")) {
+    if (contents.includes(needle)) {
       return file
     }
   }
@@ -237,8 +270,8 @@ export async function getProjectConfig(
 
   if (
     !projectInfo ||
-    !projectInfo.tailwindConfigFile ||
-    !projectInfo.tailwindCssFile
+    !projectInfo.tailwindCssFile ||
+    (projectInfo.tailwindVersion === "v3" && !projectInfo.tailwindConfigFile)
   ) {
     return null
   }
@@ -249,7 +282,7 @@ export async function getProjectConfig(
     tsx: projectInfo.isTsx,
     style: "new-york",
     tailwind: {
-      config: projectInfo.tailwindConfigFile,
+      config: projectInfo.tailwindConfigFile ?? "",
       baseColor: "zinc",
       css: projectInfo.tailwindCssFile,
       cssVariables: true,

packages/shadcn/test/fixtures/frameworks/next-app-src/package.json

@@ -0,0 +1,14 @@
+{
+  "name": "next-app-src",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "dev": "next dev",
+    "build": "next build",
+    "start": "next start",
+    "lint": "next lint"
+  },
+  "dependencies": {
+    "tailwindcss": "3.1.2"
+  }
+}

packages/shadcn/test/fixtures/frameworks/next-app/package.json

@@ -7,5 +7,8 @@
     "build": "next build",
     "start": "next start",
     "lint": "next lint"
+  },
+  "dependencies": {
+    "tailwindcss": "^3.0.0"
   }
 }

packages/shadcn/test/fixtures/frameworks/next-pages-src/package.json

@@ -7,5 +7,8 @@
     "build": "next build",
     "start": "next start",
     "lint": "next lint"
+  },
+  "dependencies": {
+    "tailwindcss": "^4.0.0"
   }
 }

packages/shadcn/test/fixtures/frameworks/next-pages-src/src/styles/globals.css

@@ -1,27 +1 @@
-@tailwind base;
-@tailwind components;
-@tailwind utilities;
-
-:root {
-  --foreground-rgb: 0, 0, 0;
-  --background-start-rgb: 214, 219, 220;
-  --background-end-rgb: 255, 255, 255;
-}
-
-@media (prefers-color-scheme: dark) {
-  :root {
-    --foreground-rgb: 255, 255, 255;
-    --background-start-rgb: 0, 0, 0;
-    --background-end-rgb: 0, 0, 0;
-  }
-}
-
-body {
-  color: rgb(var(--foreground-rgb));
-  background: linear-gradient(
-      to bottom,
-      transparent,
-      rgb(var(--background-end-rgb))
-    )
-    rgb(var(--background-start-rgb));
-}
+@import "tailwindcss";

packages/shadcn/test/fixtures/frameworks/next-pages/package.json

@@ -7,5 +7,8 @@
     "build": "next build",
     "start": "next start",
     "lint": "next lint"
+  },
+  "devDependencies": {
+    "tailwindcss": "4.1.2"
   }
 }

packages/shadcn/test/fixtures/frameworks/next-pages/styles/globals.css

@@ -1,27 +1 @@
-@tailwind base;
-@tailwind components;
-@tailwind utilities;
-
-:root {
-  --foreground-rgb: 0, 0, 0;
-  --background-start-rgb: 214, 219, 220;
-  --background-end-rgb: 255, 255, 255;
-}
-
-@media (prefers-color-scheme: dark) {
-  :root {
-    --foreground-rgb: 255, 255, 255;
-    --background-start-rgb: 0, 0, 0;
-    --background-end-rgb: 0, 0, 0;
-  }
-}
-
-body {
-  color: rgb(var(--foreground-rgb));
-  background: linear-gradient(
-      to bottom,
-      transparent,
-      rgb(var(--background-end-rgb))
-    )
-    rgb(var(--background-start-rgb));
-}
+@import "tailwindcss";