fix: include filename and line numbers in CSS parse errors

- Add getLineAndColumn helper to calculate position from buffer index
- Add formatError helper to format errors with source location
- Update all CSS parser error messages to include filename:line:column
- Add comprehensive test coverage for error reporting
- Maintain backward compatibility when no filename provided

Fixes #19236

integrations/cli/index.test.ts

@@ -2104,3 +2104,31 @@ test(
 function withBOM(text: string): string {
   return '\uFEFF' + text
 }
+
+test(
+  'CSS parse errors should include filename and line number',
+  {
+    fs: {
+      'package.json': json`
+        {
+          "dependencies": {
+            "tailwindcss": "workspace:^",
+            "@tailwindcss/cli": "workspace:^"
+          }
+        }
+      `,
+      'broken.css': css`
+        /* Test file to reproduce the CSS parsing error */
+        .test {
+          color: red;
+          /* margin-bottom: calc(var(--spacing) * 5); */ */
+        }
+      `,
+    },
+  },
+  async ({ exec, expect }) => {
+    await expect(exec('pnpm tailwindcss --input broken.css --output dist/out.css')).rejects.toThrow(
+      /Invalid declaration.*at.*broken\.css:5:49/,
+    )
+  },
+)

packages/tailwindcss/src/css-parser.test.ts

@@ -1215,6 +1215,54 @@ describe.each(['Unix', 'Windows'])('Line endings: %s', (lineEndings) => {
         `[Error: Invalid declaration: \`bar\`]`,
       )
     })
+
+    it('should include filename and line number in error messages when from option is provided', () => {
+      expect(() => {
+        CSS.parse('/* margin-bottom: calc(var(--spacing) * 5); */ */', { from: 'test.css' })
+      }).toThrowErrorMatchingInlineSnapshot(
+        `[Error: Invalid declaration: \`*/\` at test.css:1:49]`,
+      )
+    })
+
+    it('should include filename and line number for multi-line CSS errors', () => {
+      const multiLineCss = `/* Test file */
+.test {
+  color: red;
+  /* margin-bottom: calc(var(--spacing) * 5); */ */
+}`
+      expect(() => {
+        CSS.parse(multiLineCss, { from: 'styles.css' })
+      }).toThrowErrorMatchingInlineSnapshot(
+        `[Error: Invalid declaration: \`*/\` at styles.css:4:49]`,
+      )
+    })
+
+    it('should include filename and line number for missing opening brace errors', () => {
+      const cssWithMissingBrace = `.foo {
+  color: red;
+}
+
+.bar
+  color: blue;
+}`
+      expect(() => {
+        CSS.parse(cssWithMissingBrace, { from: 'broken.css' })
+      }).toThrowErrorMatchingInlineSnapshot(
+        `[Error: Missing opening { at broken.css:7:1]`,
+      )
+    })
+
+    it('should include filename and line number for unterminated string errors', () => {
+      const cssWithUnterminatedString = `.foo {
+  content: "Hello world!
+  font-weight: bold;
+}`
+      expect(() => {
+        CSS.parse(cssWithUnterminatedString, { from: 'string-error.css' })
+      }).toThrowErrorMatchingInlineSnapshot(
+        `[Error: Unterminated string: "Hello world! at string-error.css:2:12]`,
+      )
+    })
   })
 
   it('ignores BOM at the beginning of a file', () => {
@@ -1227,4 +1275,12 @@ describe.each(['Unix', 'Windows'])('Line endings: %s', (lineEndings) => {
       },
     ])
   })
+
+  it('should not include filename when from option is not provided', () => {
+    expect(() => {
+      CSS.parse('/* margin-bottom: calc(var(--spacing) * 5); */ */')
+    }).toThrowErrorMatchingInlineSnapshot(
+      `[Error: Invalid declaration: \`*/\`]`,
+    )
+  })
 })

packages/tailwindcss/src/css-parser.ts

@@ -36,6 +36,31 @@ export interface ParseOptions {
   from?: string
 }
 
+function getLineAndColumn(input: string, position: number): { line: number; column: number } {
+  let line = 1
+  let column = 1
+  
+  for (let i = 0; i < position && i < input.length; i++) {
+    if (input.charCodeAt(i) === LINE_BREAK) {
+      line++
+      column = 1
+    } else {
+      column++
+    }
+  }
+  
+  return { line, column }
+}
+
+function formatError(message: string, source: Source | null, position: number): string {
+  if (!source) {
+    return message
+  }
+  
+  const { line, column } = getLineAndColumn(source.code, position)
+  return `${message} at ${source.file}:${line}:${column}`
+}
+
 export function parse(input: string, opts?: ParseOptions) {
   let source: Source | null = opts?.from ? { file: opts.from, code: input } : null
 
@@ -138,7 +163,7 @@ export function parse(input: string, opts?: ParseOptions) {
 
     // Start of a string.
     else if (currentChar === SINGLE_QUOTE || currentChar === DOUBLE_QUOTE) {
-      let end = parseString(input, i, currentChar)
+      let end = parseString(input, i, currentChar, source)
 
       // Adjust `buffer` to include the string.
       buffer += input.slice(i, end + 1)
@@ -192,7 +217,7 @@ export function parse(input: string, opts?: ParseOptions) {
 
         // Start of a string.
         else if (peekChar === SINGLE_QUOTE || peekChar === DOUBLE_QUOTE) {
-          j = parseString(input, j, peekChar)
+          j = parseString(input, j, peekChar, source)
         }
 
         // Start of a comment.
@@ -269,7 +294,7 @@ export function parse(input: string, opts?: ParseOptions) {
       }
 
       let declaration = parseDeclaration(buffer, colonIdx)
-      if (!declaration) throw new Error(`Invalid custom property, expected a value`)
+      if (!declaration) throw new Error(formatError(`Invalid custom property, expected a value`, source, start))
 
       if (source) {
         declaration.src = [source, start, i]
@@ -334,7 +359,7 @@ export function parse(input: string, opts?: ParseOptions) {
       let declaration = parseDeclaration(buffer)
       if (!declaration) {
         if (buffer.length === 0) continue
-        throw new Error(`Invalid declaration: \`${buffer.trim()}\``)
+        throw new Error(formatError(`Invalid declaration: \`${buffer.trim()}\``, source, bufferStart))
       }
 
       if (source) {
@@ -391,7 +416,7 @@ export function parse(input: string, opts?: ParseOptions) {
       closingBracketStack[closingBracketStack.length - 1] !== ')'
     ) {
       if (closingBracketStack === '') {
-        throw new Error('Missing opening {')
+        throw new Error(formatError('Missing opening {', source, i))
       }
 
       closingBracketStack = closingBracketStack.slice(0, -1)
@@ -453,7 +478,7 @@ export function parse(input: string, opts?: ParseOptions) {
           // Attach the declaration to the parent.
           if (parent) {
             let node = parseDeclaration(buffer, colonIdx)
-            if (!node) throw new Error(`Invalid declaration: \`${buffer.trim()}\``)
+            if (!node) throw new Error(formatError(`Invalid declaration: \`${buffer.trim()}\``, source, bufferStart))
 
             if (source) {
               node.src = [source, bufferStart, i]
@@ -492,7 +517,7 @@ export function parse(input: string, opts?: ParseOptions) {
     // `)`
     else if (currentChar === CLOSE_PAREN) {
       if (closingBracketStack[closingBracketStack.length - 1] !== ')') {
-        throw new Error('Missing opening (')
+        throw new Error(formatError('Missing opening (', source, i))
       }
 
       closingBracketStack = closingBracketStack.slice(0, -1)
@@ -534,10 +559,10 @@ export function parse(input: string, opts?: ParseOptions) {
   // have a leftover `parent`, then it means that we have an unterminated block.
   if (closingBracketStack.length > 0 && parent) {
     if (parent.kind === 'rule') {
-      throw new Error(`Missing closing } at ${parent.selector}`)
+      throw new Error(formatError(`Missing closing } at ${parent.selector}`, source, input.length))
     }
     if (parent.kind === 'at-rule') {
-      throw new Error(`Missing closing } at ${parent.name} ${parent.params}`)
+      throw new Error(formatError(`Missing closing } at ${parent.name} ${parent.params}`, source, input.length))
     }
   }
 
@@ -594,7 +619,7 @@ function parseDeclaration(
   )
 }
 
-function parseString(input: string, startIdx: number, quoteChar: number): number {
+function parseString(input: string, startIdx: number, quoteChar: number, source: Source | null = null): number {
   let peekChar: number
 
   // We need to ensure that the closing quote is the same as the opening
@@ -637,7 +662,7 @@ function parseString(input: string, startIdx: number, quoteChar: number): number
         (input.charCodeAt(i + 1) === CARRIAGE_RETURN && input.charCodeAt(i + 2) === LINE_BREAK))
     ) {
       throw new Error(
-        `Unterminated string: ${input.slice(startIdx, i + 1) + String.fromCharCode(quoteChar)}`,
+        formatError(`Unterminated string: ${input.slice(startIdx, i + 1) + String.fromCharCode(quoteChar)}`, source, startIdx)
       )
     }
 
@@ -656,7 +681,7 @@ function parseString(input: string, startIdx: number, quoteChar: number): number
       (peekChar === CARRIAGE_RETURN && input.charCodeAt(i + 1) === LINE_BREAK)
     ) {
       throw new Error(
-        `Unterminated string: ${input.slice(startIdx, i) + String.fromCharCode(quoteChar)}`,
+        formatError(`Unterminated string: ${input.slice(startIdx, i) + String.fromCharCode(quoteChar)}`, source, startIdx)
       )
     }
   }