From ecb0f20f9e413f61abbec71a82ef9c3a3efe7508 Mon Sep 17 00:00:00 2001
From: Robin Malfait <malfait.robin@gmail.com>
Date: Mon, 19 May 2025 12:10:46 +0200
Subject: [PATCH 1/6] fix older test

---
 integrations/upgrade/index.test.ts | 36 +++++++++++++++---------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/integrations/upgrade/index.test.ts b/integrations/upgrade/index.test.ts
index c70c83ddc6df..71e6bcd88911 100644
--- a/integrations/upgrade/index.test.ts
+++ b/integrations/upgrade/index.test.ts
@@ -2980,21 +2980,21 @@ test(
         }
       `,
       'src/index.vue': html`
-        <template
+        <template>
           <div class="!flex"></div>
         </template>
 
         <style>
-        @reference "./input.css";
+          @reference "./input.css";
 
-        .foo {
-          @apply !bg-red-500;
-        }
+          .foo {
+            @apply !bg-red-500;
+          }
 
-        .bar {
-          /* Do not upgrade the key: */
-          flex-shrink: 0;
-        }
+          .bar {
+            /* Do not upgrade the key: */
+            flex-shrink: 0;
+          }
         </style>
       `,
       'src/input.css': css`
@@ -3016,21 +3016,21 @@ test(
     expect(await fs.dumpFiles('./src/**/*.{css,vue}')).toMatchInlineSnapshot(`
       "
       --- ./src/index.vue ---
-      <template
+      <template>
         <div class="flex!"></div>
       </template>
 
       <style>
-      @reference "./input.css";
+        @reference "./input.css";
 
-      .foo {
-        @apply !bg-red-500;
-      }
+        .foo {
+          @apply !bg-red-500;
+        }
 
-      .bar {
-        /* Do not upgrade the key: */
-        flex-shrink: 0;
-      }
+        .bar {
+          /* Do not upgrade the key: */
+          flex-shrink: 0;
+        }
       </style>
 
       --- ./src/input.css ---

From bb61a87be89acbb7629b16291949f951e7d553d0 Mon Sep 17 00:00:00 2001
From: Robin Malfait <malfait.robin@gmail.com>
Date: Mon, 19 May 2025 12:04:01 +0200
Subject: [PATCH 2/6] add failing test

---
 integrations/upgrade/index.test.ts | 56 +++++++++++++++++++++++++++++-
 1 file changed, 55 insertions(+), 1 deletion(-)

diff --git a/integrations/upgrade/index.test.ts b/integrations/upgrade/index.test.ts
index 71e6bcd88911..f3b86dedf2f8 100644
--- a/integrations/upgrade/index.test.ts
+++ b/integrations/upgrade/index.test.ts
@@ -1,5 +1,6 @@
+import path from 'node:path'
 import { isRepoDirty } from '../../packages/@tailwindcss-upgrade/src/utils/git'
-import { candidate, css, html, js, json, test, ts } from '../utils'
+import { candidate, css, html, js, json, test, ts, yaml } from '../utils'
 
 test(
   'error when no CSS file with @tailwind is used',
@@ -2967,6 +2968,59 @@ test(
   },
 )
 
+test(
+  'upgrades can run in a pnpm workspace',
+  {
+    fs: {
+      'package.json': json`{}`,
+      'pnpm-workspace.yaml': yaml`
+        #
+        packages:
+          - project-a
+      `,
+      'project-a/package.json': json`
+        {
+          "dependencies": {
+            "tailwindcss": "^4"
+          },
+          "devDependencies": {
+            "@tailwindcss/upgrade": "workspace:^"
+          }
+        }
+      `,
+      'project-a/src/index.html': html`
+        <!-- Migrating 'ring', 'rounded' and 'outline-none' are unsafe in v4 -> v4 migrations -->
+        <div class="ring rounded outline"></div>
+
+        <!-- Variant order is also unsafe to change in v4 projects -->
+        <div class="file:hover:flex *:hover:flex"></div>
+        <div class="hover:file:flex hover:*:flex"></div>
+
+        <!-- These are safe to migrate: -->
+        <div
+          class="!flex bg-red-500/[var(--my-opacity)] [@media(pointer:fine)]:flex bg-right-bottom object-left-top"
+        ></div>
+      `,
+      'project-a/src/input.css': css`
+        @import 'tailwindcss';
+
+        .foo {
+          @apply !bg-[var(--my-color)];
+        }
+      `,
+    },
+  },
+  async ({ root, exec, fs, expect }) => {
+    let stdout = await exec('npx @tailwindcss/upgrade', {
+      cwd: path.join(root, 'project-a'),
+    })
+
+    expect(/Path .*? is not in cwd/.test(stdout)).toBe(false)
+
+    expect(await fs.dumpFiles('./project-a/src/**/*.{css,html}')).toMatchInlineSnapshot()
+  },
+)
+
 test(
   'upgrade <style> blocks carefully',
   {

From 6a5225310241435486b1292701829f999cf432b0 Mon Sep 17 00:00:00 2001
From: Robin Malfait <malfait.robin@gmail.com>
Date: Fri, 16 May 2025 21:46:17 +0200
Subject: [PATCH 3/6] =?UTF-8?q?fix=20`path=20=E2=80=A6=20not=20in=20cwd`?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 integrations/upgrade/index.test.ts            | 24 ++++++++++++++++++-
 .../src/codemods/css/analyze.ts               |  9 ++++++-
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/integrations/upgrade/index.test.ts b/integrations/upgrade/index.test.ts
index f3b86dedf2f8..07f4668f82e1 100644
--- a/integrations/upgrade/index.test.ts
+++ b/integrations/upgrade/index.test.ts
@@ -3017,7 +3017,29 @@ test(
 
     expect(/Path .*? is not in cwd/.test(stdout)).toBe(false)
 
-    expect(await fs.dumpFiles('./project-a/src/**/*.{css,html}')).toMatchInlineSnapshot()
+    expect(await fs.dumpFiles('./project-a/src/**/*.{css,html}')).toMatchInlineSnapshot(`
+      "
+      --- ./project-a/src/index.html ---
+      <!-- Migrating 'ring', 'rounded' and 'outline-none' are unsafe in v4 -> v4 migrations -->
+      <div class="ring rounded outline"></div>
+
+      <!-- Variant order is also unsafe to change in v4 projects -->
+      <div class="file:hover:flex *:hover:flex"></div>
+      <div class="hover:file:flex hover:*:flex"></div>
+
+      <!-- These are safe to migrate: -->
+      <div
+        class="flex! bg-red-500/(--my-opacity) pointer-fine:flex bg-bottom-right object-top-left"
+      ></div>
+
+      --- ./project-a/src/input.css ---
+      @import 'tailwindcss';
+
+      .foo {
+        @apply bg-(--my-color)!;
+      }
+      "
+    `)
   },
 )
 
diff --git a/packages/@tailwindcss-upgrade/src/codemods/css/analyze.ts b/packages/@tailwindcss-upgrade/src/codemods/css/analyze.ts
index 954d8ce0f869..c9af6a7a38cf 100644
--- a/packages/@tailwindcss-upgrade/src/codemods/css/analyze.ts
+++ b/packages/@tailwindcss-upgrade/src/codemods/css/analyze.ts
@@ -12,7 +12,14 @@ export async function analyze(stylesheets: Stylesheet[]) {
   let processingQueue: (() => Promise<Result>)[] = []
   let stylesheetsByFile = new DefaultMap<string, Stylesheet | null>((file) => {
     // We don't want to process ignored files (like node_modules)
-    if (isIgnored(file)) {
+    try {
+      if (isIgnored(file)) {
+        return null
+      }
+    } catch {
+      // If the file is not part of the current working directory (which can
+      // happen if you import `tailwindcss` and it's loading a shared file from
+      // pnpm) then this will throw.
       return null
     }
 

From 49990434fb5d0d40f3169ecca37405f1a2853f79 Mon Sep 17 00:00:00 2001
From: Robin Malfait <malfait.robin@gmail.com>
Date: Mon, 19 May 2025 12:09:09 +0200
Subject: [PATCH 4/6] add failing test

---
 integrations/upgrade/index.test.ts | 52 ++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/integrations/upgrade/index.test.ts b/integrations/upgrade/index.test.ts
index 07f4668f82e1..139049f400d9 100644
--- a/integrations/upgrade/index.test.ts
+++ b/integrations/upgrade/index.test.ts
@@ -3043,6 +3043,58 @@ test(
   },
 )
 
+test(
+  'upgrades can run in a pnpm workspace root',
+  {
+    fs: {
+      'pnpm-workspace.yaml': yaml`
+        #
+        packages:
+          - .
+      `,
+      'package.json': json`
+        {
+          "dependencies": {
+            "tailwindcss": "^4"
+          },
+          "devDependencies": {
+            "@tailwindcss/upgrade": "workspace:^"
+          }
+        }
+      `,
+      'src/index.html': html`
+        <!-- Migrating 'ring', 'rounded' and 'outline-none' are unsafe in v4 -> v4 migrations -->
+        <div class="ring rounded outline"></div>
+
+        <!-- Variant order is also unsafe to change in v4 projects -->
+        <div class="file:hover:flex *:hover:flex"></div>
+        <div class="hover:file:flex hover:*:flex"></div>
+
+        <!-- These are safe to migrate: -->
+        <div
+          class="!flex bg-red-500/[var(--my-opacity)] [@media(pointer:fine)]:flex bg-right-bottom object-left-top"
+        ></div>
+      `,
+      'src/input.css': css`
+        @import 'tailwindcss';
+
+        .foo {
+          @apply !bg-[var(--my-color)];
+        }
+      `,
+    },
+  },
+  async ({ exec, fs, expect }) => {
+    let stdout = await exec('npx @tailwindcss/upgrade')
+
+    expect(stdout).not.toContain(
+      'Running this command will add the dependency to the workspace root',
+    )
+
+    expect(await fs.dumpFiles('./src/**/*.{css,html}')).toMatchInlineSnapshot()
+  },
+)
+
 test(
   'upgrade <style> blocks carefully',
   {

From b75419ddd5fb6b94142513a21e7d9379839cc7a7 Mon Sep 17 00:00:00 2001
From: Robin Malfait <malfait.robin@gmail.com>
Date: Fri, 16 May 2025 22:20:54 +0200
Subject: [PATCH 5/6] allow upgrades in `pnpm` workspace root

When using pnpm with a workspace, if you happen to run the upgrade tool
in the root because some Tailwind CSS dependencies live there, then you
will get an error that you need the `--workspace-root` flag.

However, if we _always_ add it, then the upgrade tool will add
dependencies to the root, regardless of whether you are in a
sub-packages.

With this, the check doesn't happen and no error is thrown. This will
just install/bump the dependencies where necessary.
---
 integrations/upgrade/index.test.ts            | 24 ++++++++++++++++++-
 .../src/utils/packages.ts                     |  7 ++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/integrations/upgrade/index.test.ts b/integrations/upgrade/index.test.ts
index 139049f400d9..75e21c59005c 100644
--- a/integrations/upgrade/index.test.ts
+++ b/integrations/upgrade/index.test.ts
@@ -3091,7 +3091,29 @@ test(
       'Running this command will add the dependency to the workspace root',
     )
 
-    expect(await fs.dumpFiles('./src/**/*.{css,html}')).toMatchInlineSnapshot()
+    expect(await fs.dumpFiles('./src/**/*.{css,html}')).toMatchInlineSnapshot(`
+      "
+      --- ./src/index.html ---
+      <!-- Migrating 'ring', 'rounded' and 'outline-none' are unsafe in v4 -> v4 migrations -->
+      <div class="ring rounded outline"></div>
+
+      <!-- Variant order is also unsafe to change in v4 projects -->
+      <div class="file:hover:flex *:hover:flex"></div>
+      <div class="hover:file:flex hover:*:flex"></div>
+
+      <!-- These are safe to migrate: -->
+      <div
+        class="flex! bg-red-500/(--my-opacity) pointer-fine:flex bg-bottom-right object-top-left"
+      ></div>
+
+      --- ./src/input.css ---
+      @import 'tailwindcss';
+
+      .foo {
+        @apply bg-(--my-color)!;
+      }
+      "
+    `)
   },
 )
 
diff --git a/packages/@tailwindcss-upgrade/src/utils/packages.ts b/packages/@tailwindcss-upgrade/src/utils/packages.ts
index 9f7f5619f005..65f823bec7e0 100644
--- a/packages/@tailwindcss-upgrade/src/utils/packages.ts
+++ b/packages/@tailwindcss-upgrade/src/utils/packages.ts
@@ -31,6 +31,13 @@ export function pkg(base: string) {
         args.push(SAVE_DEV[packageManager] || SAVE_DEV.default)
       }
 
+      // Allow running the `pnpm` command in the workspace root without
+      // erroring. Can't just use `--workspace-root` because that will force
+      // install dependencies in the workspace root.
+      if (packageManager === 'pnpm') {
+        args.push('--ignore-workspace-root-check')
+      }
+
       let command = `${packageManager} add ${args.join(' ')}`
       try {
         return await exec(command, { cwd: base })

From 7aa017ab6c5e7c548c73050c4a6dd572c0d05fe4 Mon Sep 17 00:00:00 2001
From: Robin Malfait <malfait.robin@gmail.com>
Date: Sat, 17 May 2025 01:37:16 +0200
Subject: [PATCH 6/6] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a8a414fec022..f4ab2a1e561c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Upgrade: Do not migrate declarations that look like candidates in `<style>` blocks ([#18057](https://github.com/tailwindlabs/tailwindcss/pull/18057))
+- Upgrade: Improve `pnpm` workspaces support ([#18065](https://github.com/tailwindlabs/tailwindcss/pull/18065))
 
 ## [4.1.7] - 2025-05-15