Ensure strings are consumed as-is when using internal segment()

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Make sure `contain-*` utility variables resolve to a valid value ([#13521](https://github.com/tailwindlabs/tailwindcss/pull/13521))
+- Ensure strings are consumed as-is when using internal `segment()` ([#13608](https://github.com/tailwindlabs/tailwindcss/pull/13608))
 
 ### Changed
 

packages/tailwindcss/src/utils/segment.test.ts

@@ -21,6 +21,30 @@ it('should not split inside of curlies', () => {
   expect(segment('a:{b:c}:d', ':')).toEqual(['a', '{b:c}', 'd'])
 })
 
+it('should not split inside of double quotes', () => {
+  expect(segment('a:"b:c":d', ':')).toEqual(['a', '"b:c"', 'd'])
+})
+
+it('should not split inside of single quotes', () => {
+  expect(segment("a:'b:c':d", ':')).toEqual(['a', "'b:c'", 'd'])
+})
+
+it('should not crash when double quotes are unbalanced', () => {
+  expect(segment('a:"b:c:d', ':')).toEqual(['a', '"b:c:d'])
+})
+
+it('should not crash when single quotes are unbalanced', () => {
+  expect(segment("a:'b:c:d", ':')).toEqual(['a', "'b:c:d"])
+})
+
+it('should skip escaped double quotes', () => {
+  expect(segment(String.raw`a:"b:c\":d":e`, ':')).toEqual(['a', String.raw`"b:c\":d"`, 'e'])
+})
+
+it('should skip escaped single quotes', () => {
+  expect(segment(String.raw`a:'b:c\':d':e`, ':')).toEqual(['a', String.raw`'b:c\':d'`, 'e'])
+})
+
 it('should split by the escape sequence which is escape as well', () => {
   expect(segment('a\\b\\c\\d', '\\')).toEqual(['a', 'b', 'c', 'd'])
   expect(segment('a\\(b\\c)\\d', '\\')).toEqual(['a', '(b\\c)', 'd'])

packages/tailwindcss/src/utils/segment.ts

@@ -5,6 +5,8 @@ const OPEN_PAREN = 0x28
 const CLOSE_PAREN = 0x29
 const OPEN_BRACKET = 0x5b
 const CLOSE_BRACKET = 0x5d
+const DOUBLE_QUOTE = 0x22
+const SINGLE_QUOTE = 0x27
 
 // This is a shared buffer that is used to keep track of the current nesting level
 // of parens, brackets, and braces. It is used to determine if a character is at
@@ -30,10 +32,11 @@ export function segment(input: string, separator: string) {
   let stackPos = 0
   let parts: string[] = []
   let lastPos = 0
+  let len = input.length
 
   let separatorCode = separator.charCodeAt(0)
 
-  for (let idx = 0; idx < input.length; idx++) {
+  for (let idx = 0; idx < len; idx++) {
     let char = input.charCodeAt(idx)
 
     if (stackPos === 0 && char === separatorCode) {
@@ -47,6 +50,27 @@ export function segment(input: string, separator: string) {
         // The next character is escaped, so we skip it.
         idx += 1
         break
+      // Strings should be handled as-is until the end of the string. No need to
+      // worry about balancing parens, brackets, or curlies inside a string.
+      case SINGLE_QUOTE:
+      case DOUBLE_QUOTE:
+        while (
+          // Ensure we don't go out of bounds.
+          ++idx < len
+        ) {
+          let nextChar = input.charCodeAt(idx)
+
+          // The next character is escaped, so we skip it.
+          if (nextChar === BACKSLASH) {
+            idx += 1
+            continue
+          }
+
+          if (nextChar === char) {
+            break
+          }
+        }
+        break
       case OPEN_PAREN:
         closingBracketStack[stackPos] = CLOSE_PAREN
         stackPos++