fix: handle CRLF line endings in code frame positions

packages/vite/src/node/__tests__/__snapshots__/utils.spec.ts.snap

@@ -213,3 +213,16 @@ exports[`generateCodeFrames > works with CRLF 1`] = `
    |  ^
 "
 `;
+
+exports[`generateCodeFrames > works with CRLF given a range 1`] = `
+"
+1  |  import foo from './foo'
+2  |  
+3  |  foo()
+   |  ^^^^^
+4  |  // 1
+   |  ^^^^
+5  |  // 2
+   |  ^^
+"
+`;

packages/vite/src/node/__tests__/utils.spec.ts

@@ -279,6 +279,10 @@ describe('posToNumber', () => {
     const actual = posToNumber('a\n\nb', { line: 3, column: 0 })
     expect(actual).toBe(3)
   })
+  test('crlf', () => {
+    const actual = posToNumber('a\r\nb', { line: 2, column: 0 })
+    expect(actual).toBe(3)
+  })
   test('out of range', () => {
     const actual = posToNumber('a\nb', { line: 4, column: 0 })
     expect(actual).toBe(4)
@@ -361,6 +365,25 @@ foo()
     expectSnapshot(generateCodeFrame(sourceCrLf, { line: 2, column: 0 }))
   })
 
+  test('works with CRLF given an offset', () => {
+    const longSourceCrLf = longSource.replaceAll('\n', '\r\n')
+    // the frame should point to the same location regardless of the line endings
+    expect(
+      generateCodeFrame(longSourceCrLf, longSourceCrLf.indexOf('// 3')),
+    ).toBe(generateCodeFrame(longSource, longSource.indexOf('// 3')))
+  })
+
+  test('works with CRLF given a range', () => {
+    const longSourceCrLf = longSource.replaceAll('\n', '\r\n')
+    expectSnapshot(
+      generateCodeFrame(
+        longSourceCrLf,
+        longSourceCrLf.indexOf('foo()'),
+        longSourceCrLf.indexOf('// 2'),
+      ),
+    )
+  })
+
   test('end', () => {
     expectSnapshot(generateCodeFrame(source, 0, 0))
     expectSnapshot(generateCodeFrame(source, 0, 23))

packages/vite/src/node/utils.ts

@@ -481,6 +481,14 @@ export const splitRE: RegExp = /\r?\n/g
 
 const range: number = 2
 
+/**
+ * `splitRE` treats both LF and CRLF as a line terminator, so the terminator
+ * following a line is 2 characters long when the source uses CRLF.
+ */
+function lineTerminatorLengthAt(source: string, index: number): number {
+  return source[index] === '\r' ? 2 : 1
+}
+
 export function pad(source: string, n = 2): string {
   const lines = source.split(splitRE)
   return lines.map((l) => ` `.repeat(n) + l).join(`\n`)
@@ -499,7 +507,8 @@ export function posToNumber(source: string, pos: number | Pos): number {
   const { line, column } = pos
   let start = 0
   for (let i = 0; i < line - 1 && i < lines.length; i++) {
-    start += lines[i].length + 1
+    start += lines[i].length
+    start += lineTerminatorLengthAt(source, start)
   }
   return start + column
 }
@@ -592,12 +601,12 @@ export function generateCodeFrame(
             const underline = '^'.repeat(Math.min(length, MAX_DISPLAY_LEN))
             res.push(`${' '.repeat(lineNumberWidth)}|  ` + underline)
           }
-          count += lineLength + 1
+          count += lineTerminatorLengthAt(source, count) + lineLength
         }
       }
       break
     }
-    count++
+    count += lineTerminatorLengthAt(source, count)
   }
   return res.join('\n')
 }