Restore old behavior for class dark mode, add new selector and variant options for dark mode

CHANGELOG.md

@@ -11,10 +11,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Don't remove keyframe stops when using important utilities ([#12639](https://github.com/tailwindlabs/tailwindcss/pull/12639))
 - Don't add spaces to gradients and grid track names when followed by `calc()` ([#12704](https://github.com/tailwindlabs/tailwindcss/pull/12704))
+- Restore old behavior for `class` dark mode strategy ([#12717](https://github.com/tailwindlabs/tailwindcss/pull/12717))
 - Improve glob handling for folders with `(`, `)`, `[` or `]` in the file path ([#12715](https://github.com/tailwindlabs/tailwindcss/pull/12715))
 
 ### Added
 
+- Add new `selector` and `variant` strategies for dark mode ([#12717](https://github.com/tailwindlabs/tailwindcss/pull/12717))
 - [Oxide] New Rust template parsing engine ([#10252](https://github.com/tailwindlabs/tailwindcss/pull/10252))
 - [Oxide] Support `@import "tailwindcss"` using top-level `index.css` file ([#11205](https://github.com/tailwindlabs/tailwindcss/pull/11205), ([#11260](https://github.com/tailwindlabs/tailwindcss/pull/11260)))
 - [Oxide] Use `lightningcss` for nesting and vendor prefixes in PostCSS plugin ([#10399](https://github.com/tailwindlabs/tailwindcss/pull/10399))
@@ -25,6 +27,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Support `rtl` and `ltr` variants on same element as `dir` attribute ([#12717](https://github.com/tailwindlabs/tailwindcss/pull/12717))
 - [Oxide] Deprecate `--no-autoprefixer` flag in the CLI ([#11280](https://github.com/tailwindlabs/tailwindcss/pull/11280))
 - [Oxide] Make the Rust based parser the default ([#11394](https://github.com/tailwindlabs/tailwindcss/pull/11394))
 

src/corePlugins.js

@@ -206,8 +206,8 @@ export let variantPlugins = {
   },
 
   directionVariants: ({ addVariant }) => {
-    addVariant('ltr', ':is(:where([dir="ltr"]) &)')
-    addVariant('rtl', ':is(:where([dir="rtl"]) &)')
+    addVariant('ltr', '&:where([dir="ltr"], [dir="ltr"] *)')
+    addVariant('rtl', '&:where([dir="rtl"], [dir="rtl"] *)')
   },
 
   reducedMotionVariants: ({ addVariant }) => {
@@ -216,7 +216,7 @@ export let variantPlugins = {
   },
 
   darkVariants: ({ config, addVariant }) => {
-    let [mode, className = '.dark'] = [].concat(config('darkMode', 'media'))
+    let [mode, selector = '.dark'] = [].concat(config('darkMode', 'media'))
 
     if (mode === false) {
       mode = 'media'
@@ -227,10 +227,49 @@ export let variantPlugins = {
       ])
     }
 
-    if (mode === 'class') {
-      addVariant('dark', `:is(:where(${className}) &)`)
+    if (mode === 'variant') {
+      let formats
+      if (Array.isArray(selector)) {
+        formats = selector
+      } else if (typeof selector === 'function') {
+        formats = selector
+      } else if (typeof selector === 'string') {
+        formats = [selector]
+      }
+
+      // TODO: We could also add these warnings if the user passes a function that returns string | string[]
+      // But this is an advanced enough use case that it's probably not necessary
+      if (Array.isArray(formats)) {
+        for (let format of formats) {
+          if (format === '.dark') {
+            mode = false
+            log.warn('darkmode-variant-without-selector', [
+              'When using `variant` for `darkMode`, you must provide a selector.',
+              'Example: `darkMode: ["variant", ".your-selector &"]`',
+            ])
+          } else if (!format.includes('&')) {
+            mode = false
+            log.warn('darkmode-variant-without-ampersand', [
+              'When using `variant` for `darkMode`, your selector must contain `&`.',
+              'Example `darkMode: ["variant", ".your-selector &"]`',
+            ])
+          }
+        }
+      }
+
+      selector = formats
+    }
+
+    if (mode === 'selector') {
+      // New preferred behavior
+      addVariant('dark', `&:where(${selector}, ${selector} *)`)
     } else if (mode === 'media') {
       addVariant('dark', '@media (prefers-color-scheme: dark)')
+    } else if (mode === 'variant') {
+      addVariant('dark', selector)
+    } else if (mode === 'class') {
+      // Old behavior
+      addVariant('dark', `:is(${selector} &)`)
     }
   },
 

src/lib/setupContextUtils.js

@@ -757,14 +757,35 @@ function resolvePlugins(context, root) {
     variantPlugins['supportsVariants'],
     variantPlugins['reducedMotionVariants'],
     variantPlugins['prefersContrastVariants'],
-    variantPlugins['printVariant'],
     variantPlugins['screenVariants'],
     variantPlugins['orientationVariants'],
     variantPlugins['directionVariants'],
     variantPlugins['darkVariants'],
     variantPlugins['forcedColorsVariants'],
+    variantPlugins['printVariant'],
   ]
 
+  // This is a compatibility fix for the pre 3.4 dark mode behavior
+  // `class` retains the old behavior, but `selector` keeps the new behavior
+  let isLegacyDarkMode =
+    context.tailwindConfig.darkMode === 'class' ||
+    (Array.isArray(context.tailwindConfig.darkMode) &&
+      context.tailwindConfig.darkMode[0] === 'class')
+
+  if (isLegacyDarkMode) {
+    afterVariants = [
+      variantPlugins['supportsVariants'],
+      variantPlugins['reducedMotionVariants'],
+      variantPlugins['prefersContrastVariants'],
+      variantPlugins['darkVariants'],
+      variantPlugins['screenVariants'],
+      variantPlugins['orientationVariants'],
+      variantPlugins['directionVariants'],
+      variantPlugins['forcedColorsVariants'],
+      variantPlugins['printVariant'],
+    ]
+  }
+
   return [...corePluginList, ...beforeVariants, ...userPlugins, ...afterVariants, ...layerPlugins]
 }
 

src/util/pseudoElements.js

@@ -60,6 +60,10 @@ let elementProperties = {
   ':first-letter': ['terminal', 'jumpable'],
   ':first-line': ['terminal', 'jumpable'],
 
+  ':where': [],
+  ':is': [],
+  ':has': [],
+
   // The default value is used when the pseudo-element is not recognized
   // Because it's not recognized, we don't know if it's terminal or not
   // So we assume it can be moved AND can have user-action pseudo classes attached to it

tests/apply.test.js

@@ -34,7 +34,7 @@ let sharedHtml = html`
 
 test('@apply', () => {
   let config = {
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [{ raw: sharedHtml }],
   }
 
@@ -215,14 +215,14 @@ test('@apply', () => {
           text-align: left;
         }
       }
-      :is(:where(.dark) .apply-dark-variant) {
+      .apply-dark-variant:where(.dark, .dark *) {
         text-align: center;
       }
-      :is(:where(.dark) .apply-dark-variant:hover) {
+      .apply-dark-variant:hover:where(.dark, .dark *) {
         text-align: right;
       }
       @media (min-width: 1024px) {
-        :is(:where(.dark) .apply-dark-variant) {
+        .apply-dark-variant:where(.dark, .dark *) {
           text-align: left;
         }
       }
@@ -452,7 +452,7 @@ test('@apply', () => {
 
 test('@apply error with unknown utility', async () => {
   let config = {
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [{ raw: sharedHtml }],
   }
 
@@ -472,7 +472,7 @@ test('@apply error with unknown utility', async () => {
 
 test('@apply error with nested @screen', async () => {
   let config = {
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [{ raw: sharedHtml }],
   }
 
@@ -496,7 +496,7 @@ test('@apply error with nested @screen', async () => {
 
 test('@apply error with nested @anyatrulehere', async () => {
   let config = {
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [{ raw: sharedHtml }],
   }
 
@@ -520,7 +520,7 @@ test('@apply error with nested @anyatrulehere', async () => {
 
 test('@apply error when using .group utility', async () => {
   let config = {
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [{ raw: '<div class="foo"></div>' }],
   }
 
@@ -543,7 +543,7 @@ test('@apply error when using .group utility', async () => {
 test('@apply error when using a prefixed .group utility', async () => {
   let config = {
     prefix: 'tw-',
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [{ raw: html`<div class="foo"></div>` }],
   }
 
@@ -565,7 +565,7 @@ test('@apply error when using a prefixed .group utility', async () => {
 
 test('@apply error when using .peer utility', async () => {
   let config = {
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [{ raw: '<div class="foo"></div>' }],
   }
 
@@ -588,7 +588,7 @@ test('@apply error when using .peer utility', async () => {
 test('@apply error when using a prefixed .peer utility', async () => {
   let config = {
     prefix: 'tw-',
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [{ raw: html`<div class="foo"></div>` }],
   }
 
@@ -1972,7 +1972,7 @@ it('should maintain the correct selector when applying other utilities', () => {
 
 it('pseudo elements inside apply are moved outside of :is() or :has()', () => {
   let config = {
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [
       {
         raw: html` <div class="foo bar baz qux steve bob"></div> `,
@@ -2016,28 +2016,30 @@ it('pseudo elements inside apply are moved outside of :is() or :has()', () => {
 
   return run(input, config).then((result) => {
     expect(result.css).toMatchFormattedCss(css`
-      :is(:where(.dark) .foo):before,
-      :is(:where([dir='rtl']) :is(:where(.dark) .bar)):before,
-      :is(:where([dir='rtl']) :is(:where(.dark) .baz:hover)):before {
+      .foo:where(.dark, .dark *):before,
+      .bar:where(.dark, .dark *):where([dir='rtl'], [dir='rtl'] *):before,
+      .baz:hover:where(.dark, .dark *):where([dir='rtl'], [dir='rtl'] *):before {
         background-color: #000;
       }
-      :-webkit-any(
-          :where([dir='rtl']) :-webkit-any(:where(.dark) .qux)
+      .qux:where(.dark, .dark *):where(
+          [dir='rtl'],
+          [dir='rtl'] *
         )::-webkit-file-upload-button:hover {
         background-color: #000;
       }
-      :is(:where([dir='rtl']) :is(:where(.dark) .qux))::file-selector-button:hover {
+      .qux:where(.dark, .dark *):where([dir='rtl'], [dir='rtl'] *)::file-selector-button:hover {
         background-color: #000;
       }
-      :is(:where([dir='rtl']) :is(:where(.dark) .steve):hover):before {
+      .steve:where(.dark, .dark *):hover:where([dir='rtl'], [dir='rtl'] *):before {
         background-color: #000;
       }
-      :-webkit-any(
-          :where([dir='rtl']) :-webkit-any(:where(.dark) .bob)
-        )::-webkit-file-upload-button:hover {
+      .bob:where(.dark, .dark *):hover:where(
+          [dir='rtl'],
+          [dir='rtl'] *
+        )::-webkit-file-upload-button {
         background-color: #000;
       }
-      :is(:where([dir='rtl']) :is(:where(.dark) .bob))::file-selector-button:hover {
+      .bob:where(.dark, .dark *):hover:where([dir='rtl'], [dir='rtl'] *)::file-selector-button {
         background-color: #000;
       }
       :has([dir='rtl'] .foo:hover):before {
@@ -2055,7 +2057,7 @@ it('pseudo elements inside apply are moved outside of :is() or :has()', () => {
 
 test('::ng-deep, ::deep, ::v-deep pseudo elements are left alone', () => {
   let config = {
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [
       {
         raw: html` <div class="foo bar"></div> `,

tests/custom-separator.test.js

@@ -2,7 +2,7 @@ import { run, html, css } from './util/run'
 
 test('custom separator', () => {
   let config = {
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [
       {
         raw: html`
@@ -32,10 +32,10 @@ test('custom separator', () => {
           text-align: right;
         }
       }
-      :is(:where([dir='rtl']) .rtl_active_text-center:active) {
+      .rtl_active_text-center:active:where([dir='rtl'], [dir='rtl'] *) {
         text-align: center;
       }
-      :is(:where(.dark) .dark_focus_text-left:focus) {
+      .dark_focus_text-left:focus:where(.dark, .dark *) {
         text-align: left;
       }
     `)
@@ -44,7 +44,7 @@ test('custom separator', () => {
 
 test('dash is not supported', () => {
   let config = {
-    darkMode: 'class',
+    darkMode: 'selector',
     content: [{ raw: 'lg-hover-font-bold' }],
     separator: '-',
   }