From ac60dac880439d8318a0d243d70aea35f39ac693 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Fri, 7 Mar 2025 11:44:25 -0500
Subject: [PATCH 01/15] Add support for `@source not`

---
 .../tests/completions/at-config.test.js       | 71 +++++++++++++++++++
 .../tests/completions/completions.test.js     |  2 +-
 .../document-links/document-links.test.js     | 26 +++++++
 .../tests/hover/hover.test.js                 | 27 +++++++
 .../src/completionProvider.ts                 | 11 +++
 .../src/completions/file-paths.test.ts        |  7 ++
 .../src/completions/file-paths.ts             |  8 ++-
 .../getInvalidSourceDiagnostics.ts            |  2 +-
 .../src/documentLinksProvider.ts              |  2 +-
 .../src/hoverProvider.ts                      |  2 +-
 10 files changed, 153 insertions(+), 5 deletions(-)

diff --git a/packages/tailwindcss-language-server/tests/completions/at-config.test.js b/packages/tailwindcss-language-server/tests/completions/at-config.test.js
index 15d99ac6..181fb136 100644
--- a/packages/tailwindcss-language-server/tests/completions/at-config.test.js
+++ b/packages/tailwindcss-language-server/tests/completions/at-config.test.js
@@ -271,6 +271,51 @@ withFixture('v4/dependencies', (c) => {
     })
   })
 
+  test.concurrent('@source not', async ({ expect }) => {
+    let result = await completion({
+      text: '@source not "',
+      lang: 'css',
+      position: {
+        line: 0,
+        character: 13,
+      },
+    })
+
+    expect(result).toEqual({
+      isIncomplete: false,
+      items: [
+        {
+          label: 'index.html',
+          kind: 17,
+          data: expect.anything(),
+          textEdit: {
+            newText: 'index.html',
+            range: { start: { line: 0, character: 13 }, end: { line: 0, character: 13 } },
+          },
+        },
+        {
+          label: 'sub-dir/',
+          kind: 19,
+          command: { command: 'editor.action.triggerSuggest', title: '' },
+          data: expect.anything(),
+          textEdit: {
+            newText: 'sub-dir/',
+            range: { start: { line: 0, character: 13 }, end: { line: 0, character: 13 } },
+          },
+        },
+        {
+          label: 'tailwind.config.js',
+          kind: 17,
+          data: expect.anything(),
+          textEdit: {
+            newText: 'tailwind.config.js',
+            range: { start: { line: 0, character: 13 }, end: { line: 0, character: 13 } },
+          },
+        },
+      ],
+    })
+  })
+
   test.concurrent('@source directory', async ({ expect }) => {
     let result = await completion({
       text: '@source "./sub-dir/',
@@ -297,6 +342,32 @@ withFixture('v4/dependencies', (c) => {
     })
   })
 
+  test.concurrent('@source not directory', async ({ expect }) => {
+    let result = await completion({
+      text: '@source not "./sub-dir/',
+      lang: 'css',
+      position: {
+        line: 0,
+        character: 23,
+      },
+    })
+
+    expect(result).toEqual({
+      isIncomplete: false,
+      items: [
+        {
+          label: 'colors.js',
+          kind: 17,
+          data: expect.anything(),
+          textEdit: {
+            newText: 'colors.js',
+            range: { start: { line: 0, character: 23 }, end: { line: 0, character: 23 } },
+          },
+        },
+      ],
+    })
+  })
+
   test.concurrent('@import "…" source(…)', async ({ expect }) => {
     let result = await completion({
       text: '@import "tailwindcss" source("',
diff --git a/packages/tailwindcss-language-server/tests/completions/completions.test.js b/packages/tailwindcss-language-server/tests/completions/completions.test.js
index f5393a40..8d1253e3 100644
--- a/packages/tailwindcss-language-server/tests/completions/completions.test.js
+++ b/packages/tailwindcss-language-server/tests/completions/completions.test.js
@@ -487,7 +487,7 @@ withFixture('v4/basic', (c) => {
     })
 
     // Make sure `@slot` is NOT suggested by default
-    expect(result.items.length).toBe(7)
+    expect(result.items.length).toBe(8)
     expect(result.items).not.toEqual(
       expect.arrayContaining([
         expect.objectContaining({ kind: 14, label: '@slot', sortText: '-0000000' }),
diff --git a/packages/tailwindcss-language-server/tests/document-links/document-links.test.js b/packages/tailwindcss-language-server/tests/document-links/document-links.test.js
index 861f74c9..5dd8b66e 100644
--- a/packages/tailwindcss-language-server/tests/document-links/document-links.test.js
+++ b/packages/tailwindcss-language-server/tests/document-links/document-links.test.js
@@ -131,6 +131,32 @@ withFixture('v4/basic', (c) => {
     ],
   })
 
+  testDocumentLinks('source not: file exists', {
+    text: '@source not "index.html";',
+    lang: 'css',
+    expected: [
+      {
+        target: `file://${path
+          .resolve('./tests/fixtures/v4/basic/index.html')
+          .replace(/@/g, '%40')}`,
+        range: { start: { line: 0, character: 12 }, end: { line: 0, character: 24 } },
+      },
+    ],
+  })
+
+  testDocumentLinks('source not: file does not exist', {
+    text: '@source not "does-not-exist.html";',
+    lang: 'css',
+    expected: [
+      {
+        target: `file://${path
+          .resolve('./tests/fixtures/v4/basic/does-not-exist.html')
+          .replace(/@/g, '%40')}`,
+        range: { start: { line: 0, character: 12 }, end: { line: 0, character: 33 } },
+      },
+    ],
+  })
+
   testDocumentLinks('Directories in source(…) show links', {
     text: `
       @import "tailwindcss" source("../../");
diff --git a/packages/tailwindcss-language-server/tests/hover/hover.test.js b/packages/tailwindcss-language-server/tests/hover/hover.test.js
index 5c8bcb7f..1aaa356b 100644
--- a/packages/tailwindcss-language-server/tests/hover/hover.test.js
+++ b/packages/tailwindcss-language-server/tests/hover/hover.test.js
@@ -293,6 +293,33 @@ withFixture('v4/basic', (c) => {
     },
   })
 
+  testHover('css @source not glob expansion', {
+    exact: true,
+    lang: 'css',
+    text: `@source not "../{app,components}/**/*.jsx"`,
+    position: { line: 0, character: 23 },
+    expected: {
+      contents: {
+        kind: 'markdown',
+        value: [
+          '**Expansion**',
+          '```plaintext',
+          '- ../app/**/*.jsx',
+          '- ../components/**/*.jsx',
+          '```',
+        ].join('\n'),
+      },
+      range: {
+        start: { line: 0, character: 12 },
+        end: { line: 0, character: 42 },
+      },
+    },
+    expectedRange: {
+      start: { line: 2, character: 9 },
+      end: { line: 2, character: 18 },
+    },
+  })
+
   testHover('--theme() works inside @media queries', {
     lang: 'tailwindcss',
     text: `@media (width>=--theme(--breakpoint-xl)) { .foo { color: red; } }`,
diff --git a/packages/tailwindcss-language-service/src/completionProvider.ts b/packages/tailwindcss-language-service/src/completionProvider.ts
index 1579fd93..678ee109 100644
--- a/packages/tailwindcss-language-service/src/completionProvider.ts
+++ b/packages/tailwindcss-language-service/src/completionProvider.ts
@@ -1866,6 +1866,17 @@ function provideCssDirectiveCompletions(
       },
     })
 
+    items.push({
+      label: '@source not',
+      documentation: {
+        kind: 'markdown' as typeof MarkupKind.Markdown,
+        value: `Use the \`@source not\` directive to ignore files when scanning.\n\n[Tailwind CSS Documentation](${docsUrl(
+          state.version,
+          'functions-and-directives/#source',
+        )})`,
+      },
+    })
+
     items.push({
       label: '@plugin',
       documentation: {
diff --git a/packages/tailwindcss-language-service/src/completions/file-paths.test.ts b/packages/tailwindcss-language-service/src/completions/file-paths.test.ts
index c79fcbdd..6b9d8b7d 100644
--- a/packages/tailwindcss-language-service/src/completions/file-paths.test.ts
+++ b/packages/tailwindcss-language-service/src/completions/file-paths.test.ts
@@ -15,6 +15,7 @@ test('Detecting v3 directives that point to files', async () => {
   // The following are not supported in v3
   await expect(find('@plugin "./')).resolves.toEqual(null)
   await expect(find('@source "./')).resolves.toEqual(null)
+  await expect(find('@source not "./')).resolves.toEqual(null)
   await expect(find('@import "tailwindcss" source("./')).resolves.toEqual(null)
   await expect(find('@tailwind utilities source("./')).resolves.toEqual(null)
 })
@@ -42,6 +43,12 @@ test('Detecting v4 directives that point to files', async () => {
     suggest: 'source',
   })
 
+  await expect(find('@source not "./')).resolves.toEqual({
+    directive: 'source',
+    partial: './',
+    suggest: 'source',
+  })
+
   await expect(find('@import "tailwindcss" source("./')).resolves.toEqual({
     directive: 'import',
     partial: './',
diff --git a/packages/tailwindcss-language-service/src/completions/file-paths.ts b/packages/tailwindcss-language-service/src/completions/file-paths.ts
index a99325be..ae455d43 100644
--- a/packages/tailwindcss-language-service/src/completions/file-paths.ts
+++ b/packages/tailwindcss-language-service/src/completions/file-paths.ts
@@ -1,7 +1,8 @@
 import type { State } from '../util/state'
 
 // @config, @plugin, @source
-const PATTERN_CUSTOM_V4 = /@(?<directive>config|plugin|source)\s*(?<partial>'[^']*|"[^"]*)$/
+const PATTERN_CUSTOM_V4 =
+  /@(?<directive>config|plugin|source)(?<not>\s+not)?\s*(?<partial>'[^']*|"[^"]*)$/
 const PATTERN_CUSTOM_V3 = /@(?<directive>config)\s*(?<partial>'[^']*|"[^"]*)$/
 
 // @import … source('…')
@@ -26,6 +27,7 @@ export async function findFileDirective(state: State, text: string): Promise<Fil
 
     if (!match) return null
 
+    let isNot = match.groups.not !== undefined && match.groups.not.length > 0
     let directive = match.groups.directive
     let partial = match.groups.partial?.slice(1) ?? '' // remove leading quote
 
@@ -40,6 +42,7 @@ export async function findFileDirective(state: State, text: string): Promise<Fil
     // If we're looking at @import … source('…') or @tailwind … source('…') then
     // we want to list directories instead of files
     else if (directive === 'import' || directive === 'tailwind') {
+      if (isNot) return null
       suggest = 'directory'
     }
 
@@ -49,6 +52,9 @@ export async function findFileDirective(state: State, text: string): Promise<Fil
   let match = text.match(PATTERN_CUSTOM_V3)
   if (!match) return null
 
+  let isNot = match.groups.not !== undefined && match.groups.not.length > 0
+  if (isNot) return null
+
   let directive = match.groups.directive
   let partial = match.groups.partial.slice(1) // remove leading quote
 
diff --git a/packages/tailwindcss-language-service/src/diagnostics/getInvalidSourceDiagnostics.ts b/packages/tailwindcss-language-service/src/diagnostics/getInvalidSourceDiagnostics.ts
index 2ac52a08..d2d19157 100644
--- a/packages/tailwindcss-language-service/src/diagnostics/getInvalidSourceDiagnostics.ts
+++ b/packages/tailwindcss-language-service/src/diagnostics/getInvalidSourceDiagnostics.ts
@@ -14,7 +14,7 @@ const PATTERN_UTIL_SOURCE =
 
 // @source …
 const PATTERN_AT_SOURCE =
-  /(?:\s|^)@(?<directive>source)\s*(?<source>'[^']*'?|"[^"]*"?|[a-z]*|\)|;)/dg
+  /(?:\s|^)@(?<directive>source)\s*(?<not>not)?\s*(?<source>'[^']*'?|"[^"]*"?|[a-z]*|\)|;)/dg
 
 const HAS_DRIVE_LETTER = /^[A-Z]:/
 
diff --git a/packages/tailwindcss-language-service/src/documentLinksProvider.ts b/packages/tailwindcss-language-service/src/documentLinksProvider.ts
index 76e39ed7..ea2e7bd9 100644
--- a/packages/tailwindcss-language-service/src/documentLinksProvider.ts
+++ b/packages/tailwindcss-language-service/src/documentLinksProvider.ts
@@ -18,7 +18,7 @@ export function getDocumentLinks(
   if (state.v4) {
     patterns.push(
       /@plugin\s*(?<path>'[^']+'|"[^"]+")/g,
-      /@source\s*(?<path>'[^']+'|"[^"]+")/g,
+      /@source(?:\s+not)?\s*(?<path>'[^']+'|"[^"]+")/g,
       /@import\s*('[^']*'|"[^"]*")\s*(layer\([^)]+\)\s*)?source\((?<path>'[^']*'?|"[^"]*"?)/g,
       /@reference\s*('[^']*'|"[^"]*")\s*source\((?<path>'[^']*'?|"[^"]*"?)/g,
       /@tailwind\s*utilities\s*source\((?<path>'[^']*'?|"[^"]*"?)/g,
diff --git a/packages/tailwindcss-language-service/src/hoverProvider.ts b/packages/tailwindcss-language-service/src/hoverProvider.ts
index eb5a7d1c..0a110bd7 100644
--- a/packages/tailwindcss-language-service/src/hoverProvider.ts
+++ b/packages/tailwindcss-language-service/src/hoverProvider.ts
@@ -168,7 +168,7 @@ async function provideSourceGlobHover(
 
   let text = getTextWithoutComments(document, 'css', range)
 
-  let pattern = /@source\s*(?<path>'[^']+'|"[^"]+")/dg
+  let pattern = /@source(?:\s+not)?\s*(?<path>'[^']+'|"[^"]+")/dg
 
   for (let match of findAll(pattern, text)) {
     let path = match.groups.path.slice(1, -1)

From 53095e4bd6687fbca6a22b4ca897342514ba4e17 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Fri, 7 Mar 2025 12:03:39 -0500
Subject: [PATCH 02/15] Refactor

---
 .../src/hoverProvider.ts                      | 26 +++++++++++--------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/packages/tailwindcss-language-service/src/hoverProvider.ts b/packages/tailwindcss-language-service/src/hoverProvider.ts
index 0a110bd7..39ee3596 100644
--- a/packages/tailwindcss-language-service/src/hoverProvider.ts
+++ b/packages/tailwindcss-language-service/src/hoverProvider.ts
@@ -168,19 +168,23 @@ async function provideSourceGlobHover(
 
   let text = getTextWithoutComments(document, 'css', range)
 
-  let pattern = /@source(?:\s+not)?\s*(?<path>'[^']+'|"[^"]+")/dg
+  let patterns = [
+    /@source(?:\s+not)?\s*(?<glob>'[^']+'|"[^"]+")/dg,
+  ]
 
-  for (let match of findAll(pattern, text)) {
-    let path = match.groups.path.slice(1, -1)
+  let matches = patterns.flatMap((pattern) => findAll(pattern, text))
 
-    // Ignore paths that don't need brace expansion
-    if (!path.includes('{') || !path.includes('}')) continue
+  for (let match of matches) {
+    let glob = match.groups.glob.slice(1, -1)
+
+    // Ignore globs that don't need brace expansion
+    if (!glob.includes('{') || !glob.includes('}')) continue
 
-    // Ignore paths that don't contain the current position
+    // Ignore glob that don't contain the current position
     let slice: Range = absoluteRange(
       {
-        start: indexToPosition(text, match.indices.groups.path[0]),
-        end: indexToPosition(text, match.indices.groups.path[1]),
+        start: indexToPosition(text, match.indices.groups.glob[0]),
+        end: indexToPosition(text, match.indices.groups.glob[1]),
       },
       range,
     )
@@ -188,8 +192,8 @@ async function provideSourceGlobHover(
     if (!isWithinRange(position, slice)) continue
 
     // Perform brace expansion
-    let paths = new Set(braces.expand(path))
-    if (paths.size < 2) continue
+    let expanded = new Set(braces.expand(glob))
+    if (expanded.size < 2) continue
 
     return {
       range: slice,
@@ -197,7 +201,7 @@ async function provideSourceGlobHover(
         //
         '**Expansion**',
         '```plaintext',
-        ...Array.from(paths, (path) => `- ${path}`),
+        ...Array.from(expanded, (entry) => `- ${entry}`),
         '```',
       ]),
     }

From 7032385397f8f7d99414cc609ae1f90bc6f2d948 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Fri, 7 Mar 2025 11:55:42 -0500
Subject: [PATCH 03/15] =?UTF-8?q?Add=20support=20for=20`@source=20inline(?=
 =?UTF-8?q?=E2=80=A6)`=20and=20`@source=20not=20inline(=E2=80=A6)`?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../tests/completions/at-config.test.js       | 26 +++++++
 .../document-links/document-links.test.js     | 12 ++++
 .../tests/hover/hover.test.js                 | 68 +++++++++++++++++++
 .../src/completions/file-paths.test.ts        |  9 +++
 .../src/completions/file-paths.ts             |  2 +
 .../getInvalidSourceDiagnostics.ts            |  7 +-
 .../src/hoverProvider.ts                      |  1 +
 7 files changed, 124 insertions(+), 1 deletion(-)

diff --git a/packages/tailwindcss-language-server/tests/completions/at-config.test.js b/packages/tailwindcss-language-server/tests/completions/at-config.test.js
index 181fb136..60ee1495 100644
--- a/packages/tailwindcss-language-server/tests/completions/at-config.test.js
+++ b/packages/tailwindcss-language-server/tests/completions/at-config.test.js
@@ -368,6 +368,32 @@ withFixture('v4/dependencies', (c) => {
     })
   })
 
+  test.concurrent('@source inline(…)', async ({ expect }) => {
+    let result = await completion({
+      text: '@source inline("',
+      lang: 'css',
+      position: {
+        line: 0,
+        character: 16,
+      },
+    })
+
+    expect(result).toEqual(null)
+  })
+
+  test.concurrent('@source not inline(…)', async ({ expect }) => {
+    let result = await completion({
+      text: '@source not inline("',
+      lang: 'css',
+      position: {
+        line: 0,
+        character: 20,
+      },
+    })
+
+    expect(result).toEqual(null)
+  })
+
   test.concurrent('@import "…" source(…)', async ({ expect }) => {
     let result = await completion({
       text: '@import "tailwindcss" source("',
diff --git a/packages/tailwindcss-language-server/tests/document-links/document-links.test.js b/packages/tailwindcss-language-server/tests/document-links/document-links.test.js
index 5dd8b66e..0fc76cb6 100644
--- a/packages/tailwindcss-language-server/tests/document-links/document-links.test.js
+++ b/packages/tailwindcss-language-server/tests/document-links/document-links.test.js
@@ -157,6 +157,18 @@ withFixture('v4/basic', (c) => {
     ],
   })
 
+  testDocumentLinks('@source inline(…)', {
+    text: '@source inline("m-{1,2,3}");',
+    lang: 'css',
+    expected: [],
+  })
+
+  testDocumentLinks('@source not inline(…)', {
+    text: '@source not inline("m-{1,2,3}");',
+    lang: 'css',
+    expected: [],
+  })
+
   testDocumentLinks('Directories in source(…) show links', {
     text: `
       @import "tailwindcss" source("../../");
diff --git a/packages/tailwindcss-language-server/tests/hover/hover.test.js b/packages/tailwindcss-language-server/tests/hover/hover.test.js
index 1aaa356b..ac97e414 100644
--- a/packages/tailwindcss-language-server/tests/hover/hover.test.js
+++ b/packages/tailwindcss-language-server/tests/hover/hover.test.js
@@ -320,6 +320,74 @@ withFixture('v4/basic', (c) => {
     },
   })
 
+  testHover('css @source inline glob expansion', {
+    exact: true,
+    lang: 'css',
+    text: `@source inline("{hover:,active:,}m-{1,2,3}")`,
+    position: { line: 0, character: 23 },
+    expected: {
+      contents: {
+        kind: 'markdown',
+        value: [
+          '**Expansion**',
+          '```plaintext',
+          '- hover:m-1',
+          '- hover:m-2',
+          '- hover:m-3',
+          '- active:m-1',
+          '- active:m-2',
+          '- active:m-3',
+          '- m-1',
+          '- m-2',
+          '- m-3',
+          '```',
+        ].join('\n'),
+      },
+      range: {
+        start: { line: 0, character: 15 },
+        end: { line: 0, character: 43 },
+      },
+    },
+    expectedRange: {
+      start: { line: 2, character: 9 },
+      end: { line: 2, character: 15 },
+    },
+  })
+
+  testHover('css @source not inline glob expansion', {
+    exact: true,
+    lang: 'css',
+    text: `@source not inline("{hover:,active:,}m-{1,2,3}")`,
+    position: { line: 0, character: 23 },
+    expected: {
+      contents: {
+        kind: 'markdown',
+        value: [
+          '**Expansion**',
+          '```plaintext',
+          '- hover:m-1',
+          '- hover:m-2',
+          '- hover:m-3',
+          '- active:m-1',
+          '- active:m-2',
+          '- active:m-3',
+          '- m-1',
+          '- m-2',
+          '- m-3',
+          '```',
+        ].join('\n'),
+      },
+      range: {
+        start: { line: 0, character: 19 },
+        end: { line: 0, character: 47 },
+      },
+    },
+    expectedRange: {
+      start: { line: 2, character: 9 },
+      end: { line: 2, character: 18 },
+    },
+  })
+
   testHover('--theme() works inside @media queries', {
     lang: 'tailwindcss',
     text: `@media (width>=--theme(--breakpoint-xl)) { .foo { color: red; } }`,
diff --git a/packages/tailwindcss-language-service/src/completions/file-paths.test.ts b/packages/tailwindcss-language-service/src/completions/file-paths.test.ts
index 6b9d8b7d..ed521392 100644
--- a/packages/tailwindcss-language-service/src/completions/file-paths.test.ts
+++ b/packages/tailwindcss-language-service/src/completions/file-paths.test.ts
@@ -61,3 +61,12 @@ test('Detecting v4 directives that point to files', async () => {
     suggest: 'directory',
   })
 })
+
+test('@source inline is ignored', async () => {
+  function find(text: string) {
+    return findFileDirective({ enabled: true, v4: true }, text)
+  }
+
+  await expect(find('@source inline("')).resolves.toEqual(null)
+  await expect(find('@source not inline("')).resolves.toEqual(null)
+})
diff --git a/packages/tailwindcss-language-service/src/completions/file-paths.ts b/packages/tailwindcss-language-service/src/completions/file-paths.ts
index ae455d43..acf4f9fa 100644
--- a/packages/tailwindcss-language-service/src/completions/file-paths.ts
+++ b/packages/tailwindcss-language-service/src/completions/file-paths.ts
@@ -1,6 +1,8 @@
 import type { State } from '../util/state'
 
 // @config, @plugin, @source
+// - @source inline("…") is *not* a file directive
+// - @source not inline("…") is *not* a file directive
 const PATTERN_CUSTOM_V4 =
   /@(?<directive>config|plugin|source)(?<not>\s+not)?\s*(?<partial>'[^']*|"[^"]*)$/
 const PATTERN_CUSTOM_V3 = /@(?<directive>config)\s*(?<partial>'[^']*|"[^"]*)$/
diff --git a/packages/tailwindcss-language-service/src/diagnostics/getInvalidSourceDiagnostics.ts b/packages/tailwindcss-language-service/src/diagnostics/getInvalidSourceDiagnostics.ts
index d2d19157..24fdcd9c 100644
--- a/packages/tailwindcss-language-service/src/diagnostics/getInvalidSourceDiagnostics.ts
+++ b/packages/tailwindcss-language-service/src/diagnostics/getInvalidSourceDiagnostics.ts
@@ -14,7 +14,7 @@ const PATTERN_UTIL_SOURCE =
 
 // @source …
 const PATTERN_AT_SOURCE =
-  /(?:\s|^)@(?<directive>source)\s*(?<not>not)?\s*(?<source>'[^']*'?|"[^"]*"?|[a-z]*|\)|;)/dg
+  /(?:\s|^)@(?<directive>source)\s*(?<not>not)?\s*(?<source>'[^']*'?|"[^"]*"?|[a-z]*(?:\([^)]+\))?|\)|;)/dg
 
 const HAS_DRIVE_LETTER = /^[A-Z]:/
 
@@ -135,6 +135,11 @@ export function getInvalidSourceDiagnostics(
         })
       }
 
+      // `@source inline(…)` is fine
+      else if (directive === 'source' && source.startsWith('inline(')) {
+        //
+      }
+
       // - `@import "tailwindcss" source(no)`
       // - `@tailwind utilities source('')`
       else if (directive === 'source' && source !== 'none' && !isQuoted) {
diff --git a/packages/tailwindcss-language-service/src/hoverProvider.ts b/packages/tailwindcss-language-service/src/hoverProvider.ts
index 39ee3596..1db68bed 100644
--- a/packages/tailwindcss-language-service/src/hoverProvider.ts
+++ b/packages/tailwindcss-language-service/src/hoverProvider.ts
@@ -170,6 +170,7 @@ async function provideSourceGlobHover(
 
   let patterns = [
     /@source(?:\s+not)?\s*(?<glob>'[^']+'|"[^"]+")/dg,
+    /@source(?:\s+not)?\s*inline\((?<glob>'[^']+'|"[^"]+")/dg,
   ]
 
   let matches = patterns.flatMap((pattern) => findAll(pattern, text))

From a96c96525857e563253f6a5698daa3d0a7ab26f0 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Tue, 18 Mar 2025 13:17:42 -0400
Subject: [PATCH 04/15] Emit code lenses from the language service

---
 .../tailwindcss-language-server/src/projects.ts  | 15 +++++++++++++++
 packages/tailwindcss-language-server/src/tw.ts   | 13 +++++++++++++
 .../tests/utils/client.ts                        | 16 ++++++++++++++++
 .../src/codeLensProvider.ts                      | 13 +++++++++++++
 .../src/util/state.ts                            |  2 ++
 packages/vscode-tailwindcss/package.json         |  6 ++++++
 6 files changed, 65 insertions(+)
 create mode 100644 packages/tailwindcss-language-service/src/codeLensProvider.ts

diff --git a/packages/tailwindcss-language-server/src/projects.ts b/packages/tailwindcss-language-server/src/projects.ts
index b55ee078..3c885e29 100644
--- a/packages/tailwindcss-language-server/src/projects.ts
+++ b/packages/tailwindcss-language-server/src/projects.ts
@@ -15,6 +15,8 @@ import type {
   Disposable,
   DocumentLinkParams,
   DocumentLink,
+  CodeLensParams,
+  CodeLens,
 } from 'vscode-languageserver/node'
 import { FileChangeType } from 'vscode-languageserver/node'
 import type { TextDocument } from 'vscode-languageserver-textdocument'
@@ -35,6 +37,7 @@ import stackTrace from 'stack-trace'
 import extractClassNames from './lib/extractClassNames'
 import { klona } from 'klona/full'
 import { doHover } from '@tailwindcss/language-service/src/hoverProvider'
+import { getCodeLens } from '@tailwindcss/language-service/src/codeLensProvider'
 import { Resolver } from './resolver'
 import {
   doComplete,
@@ -110,6 +113,7 @@ export interface ProjectService {
   onColorPresentation(params: ColorPresentationParams): Promise<ColorPresentation[]>
   onCodeAction(params: CodeActionParams): Promise<CodeAction[]>
   onDocumentLinks(params: DocumentLinkParams): Promise<DocumentLink[]>
+  onCodeLens(params: CodeLensParams): Promise<CodeLens[]>
   sortClassLists(classLists: string[]): string[]
 
   dependencies(): Iterable<string>
@@ -1177,6 +1181,17 @@ export async function createProjectService(
         return doHover(state, document, params.position)
       }, null)
     },
+    async onCodeLens(params: CodeLensParams): Promise<CodeLens[]> {
+      return withFallback(async () => {
+        if (!state.enabled) return null
+        let document = documentService.getDocument(params.textDocument.uri)
+        if (!document) return null
+        let settings = await state.editor.getConfiguration(document.uri)
+        if (!settings.tailwindCSS.codeLens) return null
+        if (await isExcluded(state, document)) return null
+        return getCodeLens(state, document)
+      }, null)
+    },
     async onCompletion(params: CompletionParams): Promise<CompletionList> {
       return withFallback(async () => {
         if (!state.enabled) return null
diff --git a/packages/tailwindcss-language-server/src/tw.ts b/packages/tailwindcss-language-server/src/tw.ts
index 35da9386..fc6a87a8 100644
--- a/packages/tailwindcss-language-server/src/tw.ts
+++ b/packages/tailwindcss-language-server/src/tw.ts
@@ -19,6 +19,8 @@ import type {
   DocumentLink,
   InitializeResult,
   WorkspaceFolder,
+  CodeLensParams,
+  CodeLens,
 } from 'vscode-languageserver/node'
 import {
   CompletionRequest,
@@ -30,6 +32,7 @@ import {
   FileChangeType,
   DocumentLinkRequest,
   TextDocumentSyncKind,
+  CodeLensRequest,
 } from 'vscode-languageserver/node'
 import { URI } from 'vscode-uri'
 import normalizePath from 'normalize-path'
@@ -757,6 +760,7 @@ export class TW {
     this.connection.onDocumentColor(this.onDocumentColor.bind(this))
     this.connection.onColorPresentation(this.onColorPresentation.bind(this))
     this.connection.onCodeAction(this.onCodeAction.bind(this))
+    this.connection.onCodeLens(this.onCodeLens.bind(this))
     this.connection.onDocumentLinks(this.onDocumentLinks.bind(this))
     this.connection.onRequest(this.onRequest.bind(this))
   }
@@ -809,6 +813,7 @@ export class TW {
     capabilities.add(HoverRequest.type, { documentSelector: null })
     capabilities.add(DocumentColorRequest.type, { documentSelector: null })
     capabilities.add(CodeActionRequest.type, { documentSelector: null })
+    capabilities.add(CodeLensRequest.type, { documentSelector: null })
     capabilities.add(DocumentLinkRequest.type, { documentSelector: null })
 
     capabilities.add(CompletionRequest.type, {
@@ -931,6 +936,11 @@ export class TW {
     return this.getProject(params.textDocument)?.onCodeAction(params) ?? null
   }
 
+  async onCodeLens(params: CodeLensParams): Promise<CodeLens[]> {
+    await this.init()
+    return this.getProject(params.textDocument)?.onCodeLens(params) ?? null
+  }
+
   async onDocumentLinks(params: DocumentLinkParams): Promise<DocumentLink[]> {
     await this.init()
     return this.getProject(params.textDocument)?.onDocumentLinks(params) ?? null
@@ -961,6 +971,9 @@ export class TW {
           hoverProvider: true,
           colorProvider: true,
           codeActionProvider: true,
+          codeLensProvider: {
+            resolveProvider: false,
+          },
           documentLinkProvider: {},
           completionProvider: {
             resolveProvider: true,
diff --git a/packages/tailwindcss-language-server/tests/utils/client.ts b/packages/tailwindcss-language-server/tests/utils/client.ts
index d6d317bb..fcd0387d 100644
--- a/packages/tailwindcss-language-server/tests/utils/client.ts
+++ b/packages/tailwindcss-language-server/tests/utils/client.ts
@@ -1,6 +1,8 @@
 import type { Settings } from '@tailwindcss/language-service/src/util/state'
 import {
   ClientCapabilities,
+  CodeLens,
+  CodeLensRequest,
   CompletionList,
   CompletionParams,
   Diagnostic,
@@ -94,6 +96,11 @@ export interface ClientDocument {
    */
   reopen(): Promise<void>
 
+  /**
+   * Code lenses in the document
+   */
+  codeLenses(): Promise<CodeLens[] | null>
+
   /**
    * The diagnostics for the current version of this document
    */
@@ -677,6 +684,14 @@ export async function createClientWorkspace({
       return results
     }
 
+    async function codeLenses() {
+      return await conn.sendRequest(CodeLensRequest.type, {
+        textDocument: {
+          uri: uri.toString(),
+        },
+      })
+    }
+
     return {
       uri,
       reopen,
@@ -687,6 +702,7 @@ export async function createClientWorkspace({
       symbols,
       completions,
       diagnostics,
+      codeLenses,
     }
   }
 
diff --git a/packages/tailwindcss-language-service/src/codeLensProvider.ts b/packages/tailwindcss-language-service/src/codeLensProvider.ts
new file mode 100644
index 00000000..98cf4fb6
--- /dev/null
+++ b/packages/tailwindcss-language-service/src/codeLensProvider.ts
@@ -0,0 +1,13 @@
+import type { TextDocument } from 'vscode-languageserver-textdocument'
+import type { State } from './util/state'
+import type { CodeLens } from 'vscode-languageserver'
+
+export async function getCodeLens(state: State, doc: TextDocument): Promise<CodeLens[]> {
+  if (!state.enabled) return []
+
+  let groups: CodeLens[][] = await Promise.all([
+    //
+  ])
+
+  return groups.flat()
+}
diff --git a/packages/tailwindcss-language-service/src/util/state.ts b/packages/tailwindcss-language-service/src/util/state.ts
index 3bdb1bc4..723ffacb 100644
--- a/packages/tailwindcss-language-service/src/util/state.ts
+++ b/packages/tailwindcss-language-service/src/util/state.ts
@@ -49,6 +49,7 @@ export type TailwindCssSettings = {
   classFunctions: string[]
   suggestions: boolean
   hovers: boolean
+  codeLens: boolean
   codeActions: boolean
   validate: boolean
   showPixelEquivalents: boolean
@@ -185,6 +186,7 @@ export function getDefaultTailwindSettings(): Settings {
       classAttributes: ['class', 'className', 'ngClass', 'class:list'],
       classFunctions: [],
       codeActions: true,
+      codeLens: true,
       hovers: true,
       suggestions: true,
       validate: true,
diff --git a/packages/vscode-tailwindcss/package.json b/packages/vscode-tailwindcss/package.json
index 036ca936..876a661b 100644
--- a/packages/vscode-tailwindcss/package.json
+++ b/packages/vscode-tailwindcss/package.json
@@ -210,6 +210,12 @@
           "markdownDescription": "Enable code actions.",
           "scope": "language-overridable"
         },
+        "tailwindCSS.codeLens": {
+          "type": "boolean",
+          "default": true,
+          "markdownDescription": "Enable code lens.",
+          "scope": "language-overridable"
+        },
         "tailwindCSS.colorDecorators": {
           "type": "boolean",
           "default": true,

From 7bd975fe6e628599918c380613e729fd01cb15fc Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Tue, 18 Mar 2025 13:21:44 -0400
Subject: [PATCH 05/15] =?UTF-8?q?Show=20estimated=20number=20of=20classes?=
 =?UTF-8?q?=20generated=20above=20to=20`@source=20inline(=E2=80=A6)`?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../tailwindcss-language-server/package.json  |  1 +
 .../tests/code-lens/source-inline.test.ts     | 39 ++++++++++++++++++
 .../tailwindcss-language-service/package.json |  1 +
 .../src/codeLensProvider.ts                   | 40 ++++++++++++++++++-
 4 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts

diff --git a/packages/tailwindcss-language-server/package.json b/packages/tailwindcss-language-server/package.json
index 5ed431fb..fa0a7e91 100644
--- a/packages/tailwindcss-language-server/package.json
+++ b/packages/tailwindcss-language-server/package.json
@@ -42,6 +42,7 @@
     "@tailwindcss/line-clamp": "0.4.2",
     "@tailwindcss/oxide": "^4.0.0-alpha.19",
     "@tailwindcss/typography": "0.5.7",
+    "@types/braces": "3.0.1",
     "@types/color-name": "^1.1.3",
     "@types/culori": "^2.1.0",
     "@types/debounce": "1.2.0",
diff --git a/packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts b/packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts
new file mode 100644
index 00000000..8823e77b
--- /dev/null
+++ b/packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts
@@ -0,0 +1,39 @@
+import { expect } from 'vitest'
+import { css, defineTest } from '../../src/testing'
+import { createClient } from '../utils/client'
+
+defineTest({
+  name: 'Code lenses are displayed for @source inline(…)',
+  fs: {
+    'app.css': css`
+      @import 'tailwindcss';
+    `,
+  },
+  prepare: async ({ root }) => ({
+    client: await createClient({ root }),
+  }),
+  handle: async ({ client }) => {
+    let document = await client.open({
+      lang: 'css',
+      text: css`
+        @import 'tailwindcss';
+        @source inline("{,{hover,focus}:}{flex,underline,bg-red-{50,{100..900.100},950}}");
+      `,
+    })
+
+    let lenses = await document.codeLenses()
+
+    expect(lenses).toEqual([
+      {
+        range: {
+          start: { line: 1, character: 15 },
+          end: { line: 1, character: 81 },
+        },
+        command: {
+          title: 'Generates 15 classes',
+          command: '',
+        },
+      },
+    ])
+  },
+})
diff --git a/packages/tailwindcss-language-service/package.json b/packages/tailwindcss-language-service/package.json
index d5fddaaa..e73f6ca3 100644
--- a/packages/tailwindcss-language-service/package.json
+++ b/packages/tailwindcss-language-service/package.json
@@ -40,6 +40,7 @@
     "vscode-languageserver-textdocument": "1.0.11"
   },
   "devDependencies": {
+    "@types/braces": "3.0.1",
     "@types/css.escape": "^1.5.2",
     "@types/dedent": "^0.7.2",
     "@types/line-column": "^1.0.2",
diff --git a/packages/tailwindcss-language-service/src/codeLensProvider.ts b/packages/tailwindcss-language-service/src/codeLensProvider.ts
index 98cf4fb6..820a2160 100644
--- a/packages/tailwindcss-language-service/src/codeLensProvider.ts
+++ b/packages/tailwindcss-language-service/src/codeLensProvider.ts
@@ -1,13 +1,51 @@
-import type { TextDocument } from 'vscode-languageserver-textdocument'
+import type { Range, TextDocument } from 'vscode-languageserver-textdocument'
 import type { State } from './util/state'
 import type { CodeLens } from 'vscode-languageserver'
+import braces from 'braces'
+import { findAll, indexToPosition } from './util/find'
+import { absoluteRange } from './util/absoluteRange'
 
 export async function getCodeLens(state: State, doc: TextDocument): Promise<CodeLens[]> {
   if (!state.enabled) return []
 
   let groups: CodeLens[][] = await Promise.all([
     //
+    sourceInlineCodeLens(state, doc),
   ])
 
   return groups.flat()
 }
+
+const SOURCE_INLINE_PATTERN = /@source(?:\s+not)?\s*inline\((?<glob>'[^']+'|"[^"]+")/dg
+async function sourceInlineCodeLens(state: State, doc: TextDocument): Promise<CodeLens[]> {
+  let text = doc.getText()
+
+  let countFormatter = new Intl.NumberFormat('en', {
+    maximumFractionDigits: 2,
+  })
+
+  let lenses: CodeLens[] = []
+
+  for (let match of findAll(SOURCE_INLINE_PATTERN, text)) {
+    let glob = match.groups.glob.slice(1, -1)
+
+    // Perform brace expansion
+    let expanded = new Set<string>(braces.expand(glob))
+    if (expanded.size < 2) continue
+
+    let slice: Range = absoluteRange({
+      start: indexToPosition(text, match.indices.groups.glob[0]),
+      end: indexToPosition(text, match.indices.groups.glob[1]),
+    })
+
+    lenses.push({
+      range: slice,
+      command: {
+        title: `Generates ${countFormatter.format(expanded.size)} classes`,
+        command: '',
+      },
+    })
+  }
+
+  return lenses
+}

From 1f84960d832be74be045d2a6ea303c4c91e08ff7 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Tue, 18 Mar 2025 13:22:35 -0400
Subject: [PATCH 06/15] Show estimated size of generated classes

---
 .../tests/code-lens/source-inline.test.ts     | 56 +++++++++++++++++++
 .../src/codeLensProvider.ts                   | 25 +++++++++
 .../src/util/estimated-class-size.ts          | 35 ++++++++++++
 .../src/util/format-bytes.ts                  | 11 ++++
 4 files changed, 127 insertions(+)
 create mode 100644 packages/tailwindcss-language-service/src/util/estimated-class-size.ts
 create mode 100644 packages/tailwindcss-language-service/src/util/format-bytes.ts

diff --git a/packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts b/packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts
index 8823e77b..e169aac0 100644
--- a/packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts
+++ b/packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts
@@ -37,3 +37,59 @@ defineTest({
     ])
   },
 })
+
+defineTest({
+  name: 'The user is warned when @source inline(…) generates a lerge amount of CSS',
+  fs: {
+    'app.css': css`
+      @import 'tailwindcss';
+    `,
+  },
+  prepare: async ({ root }) => ({
+    client: await createClient({ root }),
+  }),
+  handle: async ({ client }) => {
+    let document = await client.open({
+      lang: 'css',
+      text: css`
+        @import 'tailwindcss';
+        @source inline("{,dark:}{,{sm,md,lg,xl,2xl}:}{,{hover,focus,active}:}{flex,underline,bg-red-{50,{100..900.100},950}{,/{0..100}}}");
+      `,
+    })
+
+    let lenses = await document.codeLenses()
+
+    expect(lenses).toEqual([
+      {
+        range: {
+          start: { line: 1, character: 15 },
+          end: { line: 1, character: 129 },
+        },
+        command: {
+          title: 'Generates 14,784 classes',
+          command: '',
+        },
+      },
+      {
+        range: {
+          start: { line: 1, character: 15 },
+          end: { line: 1, character: 129 },
+        },
+        command: {
+          title: 'At least 3MB of CSS',
+          command: '',
+        },
+      },
+      {
+        range: {
+          start: { line: 1, character: 15 },
+          end: { line: 1, character: 129 },
+        },
+        command: {
+          title: 'This may slow down your bundler/browser',
+          command: '',
+        },
+      },
+    ])
+  },
+})
diff --git a/packages/tailwindcss-language-service/src/codeLensProvider.ts b/packages/tailwindcss-language-service/src/codeLensProvider.ts
index 820a2160..178560d0 100644
--- a/packages/tailwindcss-language-service/src/codeLensProvider.ts
+++ b/packages/tailwindcss-language-service/src/codeLensProvider.ts
@@ -4,6 +4,8 @@ import type { CodeLens } from 'vscode-languageserver'
 import braces from 'braces'
 import { findAll, indexToPosition } from './util/find'
 import { absoluteRange } from './util/absoluteRange'
+import { formatBytes } from './util/format-bytes'
+import { estimatedClassSize } from './util/estimated-class-size'
 
 export async function getCodeLens(state: State, doc: TextDocument): Promise<CodeLens[]> {
   if (!state.enabled) return []
@@ -38,6 +40,11 @@ async function sourceInlineCodeLens(state: State, doc: TextDocument): Promise<Co
       end: indexToPosition(text, match.indices.groups.glob[1]),
     })
 
+    let size = 0
+    for (let className of expanded) {
+      size += estimatedClassSize(className)
+    }
+
     lenses.push({
       range: slice,
       command: {
@@ -45,6 +52,24 @@ async function sourceInlineCodeLens(state: State, doc: TextDocument): Promise<Co
         command: '',
       },
     })
+
+    if (size >= 1_000_000) {
+      lenses.push({
+        range: slice,
+        command: {
+          title: `At least ${formatBytes(size)} of CSS`,
+          command: '',
+        },
+      })
+
+      lenses.push({
+        range: slice,
+        command: {
+          title: `This may slow down your bundler/browser`,
+          command: '',
+        },
+      })
+    }
   }
 
   return lenses
diff --git a/packages/tailwindcss-language-service/src/util/estimated-class-size.ts b/packages/tailwindcss-language-service/src/util/estimated-class-size.ts
new file mode 100644
index 00000000..57dc4235
--- /dev/null
+++ b/packages/tailwindcss-language-service/src/util/estimated-class-size.ts
@@ -0,0 +1,35 @@
+import { segment } from './segment'
+
+/**
+ * Calculates the approximate size of a generated class
+ *
+ * This is meant to be a lower bound, as the actual size of a class can vary
+ * depending on the actual CSS properties and values, configured theme, etc…
+ */
+export function estimatedClassSize(className: string) {
+  let size = 0
+
+  // We estimate the size using the following structure which gives a reasonable
+  // lower bound on the size of the generated CSS:
+  //
+  // .class-name {
+  //   &:variant-1 {
+  //     &:variant-2 {
+  //       …
+  //     }
+  //   }
+  // }
+
+  // Class name
+  size += 1 + className.length + 3
+  size += 2
+
+  // Variants + nesting
+  for (let [depth, variantName] of segment(className, ':').entries()) {
+    size += (depth + 1) * 2 + 2 + variantName.length + 3
+    size += (depth + 1) * 2 + 2
+  }
+
+  // ~1.95x is a rough growth factor due to the actual properties being present
+  return size * 1.95
+}
diff --git a/packages/tailwindcss-language-service/src/util/format-bytes.ts b/packages/tailwindcss-language-service/src/util/format-bytes.ts
new file mode 100644
index 00000000..a7b0b050
--- /dev/null
+++ b/packages/tailwindcss-language-service/src/util/format-bytes.ts
@@ -0,0 +1,11 @@
+const UNITS = ['byte', 'kilobyte', 'megabyte', 'gigabyte', 'terabyte', 'petabyte']
+
+export function formatBytes(n: number) {
+  let i = n == 0 ? 0 : Math.floor(Math.log(n) / Math.log(1000))
+  return new Intl.NumberFormat('en', {
+    notation: 'compact',
+    style: 'unit',
+    unit: UNITS[i],
+    unitDisplay: 'narrow',
+  }).format(n / 1000 ** i)
+}

From ca626d4c7de6a7d051a0bc35105fed89211d4c22 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Tue, 18 Mar 2025 13:22:43 -0400
Subject: [PATCH 07/15] Update lockfile

---
 pnpm-lock.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 2378a376..67d58759 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -56,6 +56,9 @@ importers:
       '@tailwindcss/typography':
         specifier: 0.5.7
         version: 0.5.7(tailwindcss@3.4.17)
+      '@types/braces':
+        specifier: 3.0.1
+        version: 3.0.1
       '@types/color-name':
         specifier: ^1.1.3
         version: 1.1.4
@@ -297,6 +300,9 @@ importers:
         specifier: 1.0.11
         version: 1.0.11
     devDependencies:
+      '@types/braces':
+        specifier: 3.0.1
+        version: 3.0.1
       '@types/css.escape':
         specifier: ^1.5.2
         version: 1.5.2

From 33a5320e45ecb375290d7d8b967a68977feda824 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Wed, 12 Mar 2025 09:38:31 -0400
Subject: [PATCH 08/15] Update changelog

---
 packages/vscode-tailwindcss/CHANGELOG.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/packages/vscode-tailwindcss/CHANGELOG.md b/packages/vscode-tailwindcss/CHANGELOG.md
index 7b9e68fa..d961fd78 100644
--- a/packages/vscode-tailwindcss/CHANGELOG.md
+++ b/packages/vscode-tailwindcss/CHANGELOG.md
@@ -4,6 +4,8 @@
 
 - Detect classes in JS/TS functions and tagged template literals with the `tailwindCSS.classFunctions` setting ([#1258](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1258))
 - v4: Make sure completions show after variants using arbitrary and bare values ([#1263](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1263))
+- v4: Add support for `@source not` ([#1262](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1262))
+- v4: Add support for `@source inline(…)` ([#1262](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1262))
 
 # 0.14.9
 

From 4377591d5e8966be3cec398be7592e63a22f9af8 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Wed, 19 Mar 2025 10:12:08 -0400
Subject: [PATCH 09/15] Refactor

---
 .../tailwindcss-language-service/src/features.ts     | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/packages/tailwindcss-language-service/src/features.ts b/packages/tailwindcss-language-service/src/features.ts
index 60181bf7..cf60ebef 100644
--- a/packages/tailwindcss-language-service/src/features.ts
+++ b/packages/tailwindcss-language-service/src/features.ts
@@ -42,12 +42,14 @@ export function supportedFeatures(version: string, mod?: unknown): Feature[] {
     return ['css-at-theme', 'layer:base', 'content-list']
   }
 
-  if (!isInsidersV3 && semver.gte(version, '4.0.0-alpha.1')) {
-    return ['css-at-theme', 'layer:base', 'content-list']
-  }
+  if (!isInsidersV3) {
+    if (semver.gte(version, '4.0.0-alpha.1')) {
+      return ['css-at-theme', 'layer:base', 'content-list']
+    }
 
-  if (!isInsidersV3 && version.startsWith('0.0.0-oxide')) {
-    return ['css-at-theme', 'layer:base', 'content-list']
+    if (version.startsWith('0.0.0-oxide')) {
+      return ['css-at-theme', 'layer:base', 'content-list']
+    }
   }
 
   if (semver.gte(version, '0.99.0')) {

From df7958d52eed90cc259191e9054f57c99c700ff9 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Wed, 19 Mar 2025 10:12:31 -0400
Subject: [PATCH 10/15] Add `features` to state

---
 packages/tailwindcss-language-server/src/projects.ts    | 5 ++++-
 packages/tailwindcss-language-service/src/util/state.ts | 3 +++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/packages/tailwindcss-language-server/src/projects.ts b/packages/tailwindcss-language-server/src/projects.ts
index 3c885e29..8f6c8ec4 100644
--- a/packages/tailwindcss-language-server/src/projects.ts
+++ b/packages/tailwindcss-language-server/src/projects.ts
@@ -216,6 +216,7 @@ export async function createProjectService(
 
   let state: State = {
     enabled: false,
+    features: [],
     completionItemData: {
       _projectKey: projectKey,
     },
@@ -466,6 +467,7 @@ export async function createProjectService(
       // and this should be determined there and passed in instead
       let features = supportedFeatures(tailwindcssVersion, tailwindcss)
       log(`supported features: ${JSON.stringify(features)}`)
+      state.features = features
 
       if (!features.includes('css-at-theme')) {
         tailwindcss = tailwindcss.default ?? tailwindcss
@@ -692,6 +694,7 @@ export async function createProjectService(
         state.v4 = true
         state.v4Fallback = true
         state.jit = true
+        state.features = features
         state.modules = {
           tailwindcss: { version: tailwindcssVersion, module: tailwindcss },
           postcss: { version: null, module: null },
@@ -1154,7 +1157,7 @@ export async function createProjectService(
     },
     tryInit,
     async dispose() {
-      state = { enabled: false }
+      state = { enabled: false, features: [] }
       for (let disposable of disposables) {
         ;(await disposable).dispose()
       }
diff --git a/packages/tailwindcss-language-service/src/util/state.ts b/packages/tailwindcss-language-service/src/util/state.ts
index 723ffacb..119e5f59 100644
--- a/packages/tailwindcss-language-service/src/util/state.ts
+++ b/packages/tailwindcss-language-service/src/util/state.ts
@@ -4,6 +4,7 @@ import type { Postcss } from 'postcss'
 import type { KeywordColor } from './color'
 import type * as culori from 'culori'
 import type { DesignSystem } from './v4'
+import type { Feature } from '../features'
 
 export type ClassNamesTree = {
   [key: string]: ClassNamesTree
@@ -142,6 +143,7 @@ export interface State {
   classListContainsMetadata?: boolean
   pluginVersions?: string
   completionItemData?: Record<string, any>
+  features: Feature[]
   // postcssPlugins?: { before: any[]; after: any[] }
 }
 
@@ -223,6 +225,7 @@ export function createState(
 ): State {
   return {
     enabled: true,
+    features: [],
     ...partial,
     editor: {
       get connection(): Connection {

From 3d57bc6bc53a74982407fb4afbbd513484d3f6c6 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Wed, 19 Mar 2025 10:15:06 -0400
Subject: [PATCH 11/15] Only show `@source not` suggestion for newer Tailwind
 CSS versions

---
 .../src/completionProvider.ts                 | 22 ++++++++++---------
 .../src/features.ts                           |  8 ++++++-
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/packages/tailwindcss-language-service/src/completionProvider.ts b/packages/tailwindcss-language-service/src/completionProvider.ts
index 678ee109..3cdd511a 100644
--- a/packages/tailwindcss-language-service/src/completionProvider.ts
+++ b/packages/tailwindcss-language-service/src/completionProvider.ts
@@ -1866,16 +1866,18 @@ function provideCssDirectiveCompletions(
       },
     })
 
-    items.push({
-      label: '@source not',
-      documentation: {
-        kind: 'markdown' as typeof MarkupKind.Markdown,
-        value: `Use the \`@source not\` directive to ignore files when scanning.\n\n[Tailwind CSS Documentation](${docsUrl(
-          state.version,
-          'functions-and-directives/#source',
-        )})`,
-      },
-    })
+    if (state.features.includes('source-not')) {
+      items.push({
+        label: '@source not',
+        documentation: {
+          kind: 'markdown' as typeof MarkupKind.Markdown,
+          value: `Use the \`@source not\` directive to ignore files when scanning.\n\n[Tailwind CSS Documentation](${docsUrl(
+            state.version,
+            'functions-and-directives/#source',
+          )})`,
+        },
+      })
+    }
 
     items.push({
       label: '@plugin',
diff --git a/packages/tailwindcss-language-service/src/features.ts b/packages/tailwindcss-language-service/src/features.ts
index cf60ebef..6aa9236e 100644
--- a/packages/tailwindcss-language-service/src/features.ts
+++ b/packages/tailwindcss-language-service/src/features.ts
@@ -15,6 +15,8 @@ export type Feature =
   | 'jit'
   | 'separator:root'
   | 'separator:options'
+  | 'source-not'
+  | 'source-inline'
 
 /**
  * Determine a list of features that are supported by the given Tailwind CSS version
@@ -39,10 +41,14 @@ export function supportedFeatures(version: string, mod?: unknown): Feature[] {
   }
 
   if (isInsidersV4) {
-    return ['css-at-theme', 'layer:base', 'content-list']
+    return ['css-at-theme', 'layer:base', 'content-list', 'source-inline', 'source-not']
   }
 
   if (!isInsidersV3) {
+    if (semver.gte(version, '4.1.0')) {
+      return ['css-at-theme', 'layer:base', 'content-list', 'source-inline', 'source-not']
+    }
+
     if (semver.gte(version, '4.0.0-alpha.1')) {
       return ['css-at-theme', 'layer:base', 'content-list']
     }

From c68e08b746db7bde271b0e822d273979c29005d6 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Wed, 19 Mar 2025 10:15:50 -0400
Subject: [PATCH 12/15] Update test

---
 .../tests/completions/completions.test.js                       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/tailwindcss-language-server/tests/completions/completions.test.js b/packages/tailwindcss-language-server/tests/completions/completions.test.js
index 8d1253e3..f5393a40 100644
--- a/packages/tailwindcss-language-server/tests/completions/completions.test.js
+++ b/packages/tailwindcss-language-server/tests/completions/completions.test.js
@@ -487,7 +487,7 @@ withFixture('v4/basic', (c) => {
     })
 
     // Make sure `@slot` is NOT suggested by default
-    expect(result.items.length).toBe(8)
+    expect(result.items.length).toBe(7)
     expect(result.items).not.toEqual(
       expect.arrayContaining([
         expect.objectContaining({ kind: 14, label: '@slot', sortText: '-0000000' }),

From 58d3b613d889bf33d92272c79db6cabc40c3cdc4 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Wed, 19 Mar 2025 10:23:17 -0400
Subject: [PATCH 13/15] Allow test harness to force-enable additional features

---
 .../tailwindcss-language-server/src/projects.ts   | 15 +++++++++++++++
 .../tests/utils/client.ts                         | 10 ++++++++++
 2 files changed, 25 insertions(+)

diff --git a/packages/tailwindcss-language-server/src/projects.ts b/packages/tailwindcss-language-server/src/projects.ts
index 8f6c8ec4..afc4515f 100644
--- a/packages/tailwindcss-language-server/src/projects.ts
+++ b/packages/tailwindcss-language-server/src/projects.ts
@@ -469,6 +469,13 @@ export async function createProjectService(
       log(`supported features: ${JSON.stringify(features)}`)
       state.features = features
 
+      if (params.initializationOptions?.testMode) {
+        state.features = [
+          ...state.features,
+          ...(params.initializationOptions.additionalFeatures ?? []),
+        ]
+      }
+
       if (!features.includes('css-at-theme')) {
         tailwindcss = tailwindcss.default ?? tailwindcss
       }
@@ -695,6 +702,14 @@ export async function createProjectService(
         state.v4Fallback = true
         state.jit = true
         state.features = features
+
+        if (params.initializationOptions?.testMode) {
+          state.features = [
+            ...state.features,
+            ...(params.initializationOptions.additionalFeatures ?? []),
+          ]
+        }
+
         state.modules = {
           tailwindcss: { version: tailwindcssVersion, module: tailwindcss },
           postcss: { version: null, module: null },
diff --git a/packages/tailwindcss-language-server/tests/utils/client.ts b/packages/tailwindcss-language-server/tests/utils/client.ts
index fcd0387d..3a860230 100644
--- a/packages/tailwindcss-language-server/tests/utils/client.ts
+++ b/packages/tailwindcss-language-server/tests/utils/client.ts
@@ -47,6 +47,7 @@ import { clearLanguageBoundariesCache } from '@tailwindcss/language-service/src/
 import { DefaultMap } from '../../src/util/default-map'
 import { connect, ConnectOptions } from './connection'
 import type { DeepPartial } from '@tailwindcss/language-service/src/types'
+import type { Feature } from '@tailwindcss/language-service/src/features'
 
 export interface DocumentDescriptor {
   /**
@@ -170,6 +171,14 @@ export interface ClientOptions extends ConnectOptions {
    * Settings to provide the server immediately when it starts
    */
   settings?: DeepPartial<Settings>
+
+  /**
+   * Additional features to force-enable
+   *
+   * These should normally be enabled by the server based on the project
+   * and the Tailwind CSS version it detects
+   */
+  features?: Feature[]
 }
 
 export interface Client extends ClientWorkspace {
@@ -394,6 +403,7 @@ export async function createClient(opts: ClientOptions): Promise<Client> {
     workspaceFolders,
     initializationOptions: {
       testMode: true,
+      additionalFeatures: opts.features,
       ...opts.options,
     },
   })

From 5a021ad6e5a2b8dbca01e2e35c571654ec3851f0 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Wed, 19 Mar 2025 10:24:35 -0400
Subject: [PATCH 14/15] Only enable `@source inline` code lenses on Tailwind
 CSS v4.1

---
 .../tests/code-lens/source-inline.test.ts              | 10 ++++++++--
 .../src/codeLensProvider.ts                            |  2 ++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts b/packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts
index e169aac0..55f6f22e 100644
--- a/packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts
+++ b/packages/tailwindcss-language-server/tests/code-lens/source-inline.test.ts
@@ -10,7 +10,10 @@ defineTest({
     `,
   },
   prepare: async ({ root }) => ({
-    client: await createClient({ root }),
+    client: await createClient({
+      root,
+      features: ['source-inline'],
+    }),
   }),
   handle: async ({ client }) => {
     let document = await client.open({
@@ -46,7 +49,10 @@ defineTest({
     `,
   },
   prepare: async ({ root }) => ({
-    client: await createClient({ root }),
+    client: await createClient({
+      root,
+      features: ['source-inline'],
+    }),
   }),
   handle: async ({ client }) => {
     let document = await client.open({
diff --git a/packages/tailwindcss-language-service/src/codeLensProvider.ts b/packages/tailwindcss-language-service/src/codeLensProvider.ts
index 178560d0..b00df983 100644
--- a/packages/tailwindcss-language-service/src/codeLensProvider.ts
+++ b/packages/tailwindcss-language-service/src/codeLensProvider.ts
@@ -20,6 +20,8 @@ export async function getCodeLens(state: State, doc: TextDocument): Promise<Code
 
 const SOURCE_INLINE_PATTERN = /@source(?:\s+not)?\s*inline\((?<glob>'[^']+'|"[^"]+")/dg
 async function sourceInlineCodeLens(state: State, doc: TextDocument): Promise<CodeLens[]> {
+  if (!state.features.includes('source-inline')) return []
+
   let text = doc.getText()
 
   let countFormatter = new Intl.NumberFormat('en', {

From 8b18f8fab2f546c2bf8ac72afad1b7a9e41bc579 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Wed, 19 Mar 2025 10:24:40 -0400
Subject: [PATCH 15/15] Update changelog

---
 packages/vscode-tailwindcss/CHANGELOG.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/vscode-tailwindcss/CHANGELOG.md b/packages/vscode-tailwindcss/CHANGELOG.md
index d961fd78..faf20065 100644
--- a/packages/vscode-tailwindcss/CHANGELOG.md
+++ b/packages/vscode-tailwindcss/CHANGELOG.md
@@ -4,8 +4,8 @@
 
 - Detect classes in JS/TS functions and tagged template literals with the `tailwindCSS.classFunctions` setting ([#1258](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1258))
 - v4: Make sure completions show after variants using arbitrary and bare values ([#1263](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1263))
-- v4: Add support for `@source not` ([#1262](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1262))
-- v4: Add support for `@source inline(…)` ([#1262](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1262))
+- v4: Add support for upcoming `@source not` feature ([#1262](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1262))
+- v4: Add support for upcoming `@source inline(…)` feature ([#1262](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1262))
 
 # 0.14.9