Improve compatibility with special default values in JS configs

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Support environment API in `@tailwindcss/vite` ([#18970](https://github.com/tailwindlabs/tailwindcss/pull/18970))
 - Preserve case of theme keys from JS configs and plugins ([#19337](https://github.com/tailwindlabs/tailwindcss/pull/19337))
 - Write source maps correctly on the CLI when using `--watch` ([#19373](https://github.com/tailwindlabs/tailwindcss/pull/19373))
+- Handle special defaults (like `ringColor.DEFAULT`) in JS configs ([#19348](https://github.com/tailwindlabs/tailwindcss/pull/19348))
 - Upgrade: Handle `future` and `experimental` config keys ([#19344](https://github.com/tailwindlabs/tailwindcss/pull/19344))
 - Try to canonicalize any arbitrary utility to a bare value ([#19379](https://github.com/tailwindlabs/tailwindcss/pull/19379))
 

integrations/upgrade/index.test.ts

@@ -2347,8 +2347,7 @@ test(
         --shadow-*: initial;
         --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
 
-        --ring-width-*: initial;
-        --ring-width: 4px;
+        --default-ring-width: 4px;
 
         --blur: var(--custom-default-blur);
 
@@ -2381,7 +2380,7 @@ test(
         <div class="blur blur-xs"></div>
         <div class="backdrop-blur backdrop-blur-xs"></div>
         <div class="rounded rounded-sm"></div>
-        <div class="ring"></div>
+        <div class="ring-3"></div>
       </div>
       "
     `)

integrations/upgrade/js-config.test.ts

@@ -34,6 +34,9 @@ test(
               steel: 'rgb(70 130 180 / <alpha-value>)',
               smoke: 'rgba(245, 245, 245, var(--smoke-alpha, <alpha-value>))',
             },
+            ringColor: {
+              DEFAULT: '#c0ffee',
+            },
             opacity: {
               superOpaque: '0.95',
             },
@@ -191,6 +194,8 @@ test(
         --color-steel: rgb(70 130 180);
         --color-smoke: rgba(245, 245, 245, var(--smoke-alpha, 1));
 
+        --default-ring-color: #c0ffee;
+
         --opacity-*: initial;
         --opacity-superOpaque: 95%;
 

packages/@tailwindcss-upgrade/src/codemods/config/migrate-js-config.ts

@@ -237,16 +237,21 @@ async function migrateTheme(
       prevSectionKey = sectionKey
     }
 
-    if (resetNamespaces.has(key[0]) && resetNamespaces.get(key[0]) === false) {
-      resetNamespaces.set(key[0], true)
-      let property = keyPathToCssProperty([key[0]])
-      if (property !== null) {
-        themeSection.push(`  ${escape(`--${property}`)}-*: initial;`)
-      }
-    }
-
     let property = keyPathToCssProperty(key)
+
     if (property !== null) {
+      if (
+        !property.startsWith('default-') &&
+        resetNamespaces.has(key[0]) &&
+        resetNamespaces.get(key[0]) === false
+      ) {
+        resetNamespaces.set(key[0], true)
+        let ns = keyPathToCssProperty([key[0]])
+        if (ns !== null) {
+          themeSection.push(`  ${escape(`--${ns}`)}-*: initial;`)
+        }
+      }
+
       themeSection.push(`  ${escape(`--${property}`)}: ${value};`)
     }
   }

packages/tailwindcss/src/compat/apply-config-to-theme.test.ts

@@ -31,6 +31,16 @@ test('config values can be merged into the theme', () => {
             normal: '0 1px 3px black',
           },
 
+          borderWidth: {
+            DEFAULT: '1.5px',
+          },
+          outlineWidth: {
+            DEFAULT: '2.5px',
+          },
+          ringWidth: {
+            DEFAULT: '3.5px',
+          },
+
           borderRadius: {
             sm: '0.33rem',
           },
@@ -57,6 +67,10 @@ test('config values can be merged into the theme', () => {
             '2xl': ['2rem'],
           },
 
+          ringColor: {
+            DEFAULT: '#fff',
+          },
+
           letterSpacing: {
             superWide: '0.25em',
           },
@@ -77,8 +91,12 @@ test('config values can be merged into the theme', () => {
           },
 
           transitionTimingFunction: {
+            DEFAULT: 'ease-in-out',
             fast: 'cubic-bezier(0, 0.55, 0.45, 1)',
           },
+          transitionDuration: {
+            DEFAULT: '1234ms',
+          },
         },
       },
       base: '/root',
@@ -125,6 +143,23 @@ test('config values can be merged into the theme', () => {
   expect(theme.resolve('100%', ['--width'])).toEqual('100%')
   expect(theme.resolve('9xs', ['--container'])).toEqual('6rem')
   expect(theme.resolve('fast', ['--ease'])).toEqual('cubic-bezier(0, 0.55, 0.45, 1)')
+
+  expect(theme.get(['--border'])).toEqual(null)
+  expect(theme.get(['--default-border-width'])).toEqual('1.5px')
+
+  expect(theme.get(['--outline'])).toEqual(null)
+  expect(theme.get(['--default-outline-width'])).toEqual('2.5px')
+
+  expect(theme.get(['--ring-color'])).toEqual(null)
+  expect(theme.get(['--default-ring-color'])).toEqual('#fff')
+
+  expect(theme.get(['--ring-width'])).toEqual(null)
+  expect(theme.get(['--default-ring-width'])).toEqual('3.5px')
+
+  expect(theme.get(['--default-transition-duration'])).toEqual('1234ms')
+
+  expect(theme.get(['--ease'])).toEqual(null)
+  expect(theme.get(['--default-transition-timing-function'])).toEqual('ease-in-out')
 })
 
 test('will reset default theme values with overwriting theme values', () => {

packages/tailwindcss/src/compat/apply-config-to-theme.ts

@@ -147,32 +147,57 @@ export function themeableValues(config: ResolvedConfig['theme']): [string[], unk
   return toAdd
 }
 
+const SPECIAL_DEFAULT_KEYS: Record<string, string> = {
+  borderWidth: 'border-width',
+  outlineWidth: 'outline-width',
+  ringColor: 'ring-color',
+  ringWidth: 'ring-width',
+  transitionDuration: 'transition-duration',
+  transitionTimingFunction: 'transition-timing-function',
+}
+
+const OLD_TO_NEW_NAMESPACE: Record<string, string> = {
+  animation: 'animate',
+  aspectRatio: 'aspect',
+  borderRadius: 'radius',
+  boxShadow: 'shadow',
+  colors: 'color',
+  containers: 'container',
+  fontFamily: 'font',
+  fontSize: 'text',
+  letterSpacing: 'tracking',
+  lineHeight: 'leading',
+  maxWidth: 'container',
+  screens: 'breakpoint',
+  transitionTimingFunction: 'ease',
+}
+
 const IS_VALID_KEY = /^[a-zA-Z0-9-_%/\.]+$/
 
 export function keyPathToCssProperty(path: string[]) {
+  // In some special cases the `DEFAULT` key did not map to a "default" utility
+  // e.g. `ringColor.DEFAULT` wasn't *just* used for `ring`. It was used for
+  // all ring utilities as the color when one wasn't specified.
+  //
+  // We place these specialty values under the `--default-*` namespace to signal
+  // that they are defaults used by (potentially) multiple utilities.
+  let specialDefault = SPECIAL_DEFAULT_KEYS[path[0]]
+  if (specialDefault && path[1] === 'DEFAULT') return `default-${specialDefault}`
+
   // The legacy container component config should not be included in the Theme
   if (path[0] === 'container') return null
 
-  path = path.slice()
-
-  if (path[0] === 'animation') path[0] = 'animate'
-  if (path[0] === 'aspectRatio') path[0] = 'aspect'
-  if (path[0] === 'borderRadius') path[0] = 'radius'
-  if (path[0] === 'boxShadow') path[0] = 'shadow'
-  if (path[0] === 'colors') path[0] = 'color'
-  if (path[0] === 'containers') path[0] = 'container'
-  if (path[0] === 'fontFamily') path[0] = 'font'
-  if (path[0] === 'fontSize') path[0] = 'text'
-  if (path[0] === 'letterSpacing') path[0] = 'tracking'
-  if (path[0] === 'lineHeight') path[0] = 'leading'
-  if (path[0] === 'maxWidth') path[0] = 'container'
-  if (path[0] === 'screens') path[0] = 'breakpoint'
-  if (path[0] === 'transitionTimingFunction') path[0] = 'ease'
-
   for (let part of path) {
     if (!IS_VALID_KEY.test(part)) return null
   }
 
+  // Map old v3 namespaces to new theme namespaces
+  let ns = OLD_TO_NEW_NAMESPACE[path[0]]
+  if (ns) {
+    path = path.slice()
+    path[0] = ns
+  }
+
   return (
     path
       // [1] should move into the nested object tuple. To create the CSS variable