Allow _ inside url() when using arbitrary values (#5853)

* allow for underscores in url()

* update changelog

CHANGELOG.md

@@ -30,6 +30,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix CLI `--content` option ([#5775](https://github.com/tailwindlabs/tailwindcss/pull/5775))
 - Fix before/after utilities overriding custom content values at larger breakpoints ([#5820](https://github.com/tailwindlabs/tailwindcss/pull/5820))
 - Cleanup duplicate properties ([#5830](https://github.com/tailwindlabs/tailwindcss/pull/5830))
+- Allow `_` inside `url()` when using arbitrary values ([#5853](https://github.com/tailwindlabs/tailwindcss/pull/5853))
 
 ## [3.0.0-alpha.1] - 2021-10-01
 

src/lib/expandTailwindAtRules.js

@@ -11,6 +11,8 @@ const PATTERNS = [
   /([^<>"'`\s]*\[\w*"[^"`\s]*"?\])/.source, // font-["some_font",sans-serif]
   /([^<>"'`\s]*\[\w*\('[^"'`\s]*'\)\])/.source, // bg-[url('...')]
   /([^<>"'`\s]*\[\w*\("[^"'`\s]*"\)\])/.source, // bg-[url("...")]
+  /([^<>"'`\s]*\[\w*\('[^"`\s]*'\)\])/.source, // bg-[url('...'),url('...')]
+  /([^<>"'`\s]*\[\w*\("[^'`\s]*"\)\])/.source, // bg-[url("..."),url("...")]
   /([^<>"'`\s]*\['[^"'`\s]*'\])/.source, // `content-['hello']` but not `content-['hello']']`
   /([^<>"'`\s]*\["[^"'`\s]*"\])/.source, // `content-["hello"]` but not `content-["hello"]"]`
   /([^<>"'`\s]*\[[^"'`\s]+\][^<>"'`\s]*)/.source, // `fill-[#bada55]`, `fill-[#bada55]/50`

src/util/dataTypes.js

@@ -7,7 +7,22 @@ let UNDERSCORE = /_(?![^(]*\))/g // Underscore separator that is not located bet
 
 // This is not a data type, but rather a function that can normalize the
 // correct values.
-export function normalize(value) {
+export function normalize(value, isRoot = true) {
+  // Keep raw strings if it starts with `url(`
+  if (value.includes('url(')) {
+    return value
+      .split(/(url\(.*?\))/g)
+      .filter(Boolean)
+      .map((part) => {
+        if (/^url\(.*?\)$/.test(part)) {
+          return part
+        }
+
+        return normalize(part, false)
+      })
+      .join('')
+  }
+
   // Convert `_` to ` `, except for escaped underscores `\_`
   value = value
     .replace(
@@ -18,10 +33,9 @@ export function normalize(value) {
     .replace(/\\_/g, '_')
 
   // Remove leftover whitespace
-  value = value.trim()
-
-  // Keep raw strings if it starts with `url(`
-  if (value.startsWith('url(')) return value
+  if (isRoot) {
+    value = value.trim()
+  }
 
   // Add spaces around operators inside calc() that do not follow an operator
   // or '('.

src/util/pluginUtils.js

@@ -160,9 +160,18 @@ function splitAtFirst(input, delim) {
 
 export function coerceValue(types, modifier, options, tailwindConfig) {
   if (isArbitraryValue(modifier)) {
-    let [explicitType, value] = splitAtFirst(modifier.slice(1, -1), ':')
+    let arbitraryValue = modifier.slice(1, -1)
+    let [explicitType, value] = splitAtFirst(arbitraryValue, ':')
 
-    if (explicitType !== undefined && !supportedTypes.includes(explicitType)) {
+    // It could be that this resolves to `url(https` which is not a valid
+    // identifier. We currently only support "simple" words with dashes or
+    // underscores. E.g.: family-name
+    if (!/^[\w-_]+$/g.test(explicitType)) {
+      value = arbitraryValue
+    }
+
+    //
+    else if (explicitType !== undefined && !supportedTypes.includes(explicitType)) {
       return []
     }
 

tests/arbitrary-values.test.html

@@ -126,6 +126,7 @@
 
     <div class="cursor-[pointer]"></div>
     <div class="cursor-[url(hand.cur)_2_2,pointer]"></div>
+    <div class="cursor-[url('./path_to_hand.cur')_2_2,pointer]"></div>
     <div class="cursor-[var(--value)]"></div>
 
     <div class="list-['\1F44D']"></div>

tests/arbitrary-values.test.js

@@ -220,3 +220,35 @@ it('should warn and not generate if arbitrary values are ambiguous', () => {
     return expect(result.css).toMatchFormattedCss(css``)
   })
 })
+
+it('should support colons in URLs', () => {
+  let config = {
+    content: [
+      { raw: html`<div class="bg-[url('https://www.spacejam.com/1996/img/bg_stars.gif')]"></div>` },
+    ],
+  }
+
+  return run('@tailwind utilities', config).then((result) => {
+    return expect(result.css).toMatchFormattedCss(css`
+      .bg-\[url\(\'https\:\/\/www\.spacejam\.com\/1996\/img\/bg_stars\.gif\'\)\] {
+        background-image: url('https://www.spacejam.com/1996/img/bg_stars.gif');
+      }
+    `)
+  })
+})
+
+it('should support unescaped underscores in URLs', () => {
+  let config = {
+    content: [
+      { raw: html`<div class="bg-[url('brown_potato.jpg'),_url('red_tomato.png')]"></div>` },
+    ],
+  }
+
+  return run('@tailwind utilities', config).then((result) => {
+    return expect(result.css).toMatchFormattedCss(`
+      .bg-\\[url\\(\\'brown_potato\\.jpg\\'\\)\\2c _url\\(\\'red_tomato\\.png\\'\\)\\] {
+        background-image: url('brown_potato.jpg'), url('red_tomato.png');
+      }
+    `)
+  })
+})