fix: ensure absolute paths are handled correctly with `--file` option in `next lint` command for `lint-staged` compatibility (#69220)
Hello😊 Thanks for having attention to this issue.
### What?
**Fixed a bug.**
The `next lint` command's `--file` option was intended to allow users to
lint specific files directly by specifying their paths. However, it only
worked with relative paths and did not handle absolute paths correctly.
This limitation hindered the flexibility and usability of the linting
process.
Furthermore, `lint-staged` returns absolute paths when running lint
commands on staged files. Without proper handling of these absolute
paths, linting was not performed correctly, leading to issues in
automated linting workflows.
### Why?
#### Environment(results by `next info`)
```bash
Operating System:
Platform: win32
Arch: x64
Version: Windows 11 Home
Available memory (MB): 16058
Available CPU cores: 8
Binaries:
Node: 20.12.2
npm: N/A
Yarn: N/A
pnpm: N/A
Relevant Packages:
next: 14.2.6 // Latest available version is detected (14.2.6).
eslint-config-next: 14.2.6
react: 18.3.1
react-dom: 18.3.1
typescript: 5.5.4
Next.js Config:
output: N/A
```
#### Steps to Reproduce
1. Make a `js` or `jsx` file like below. this makes ESLint **error**
named `no-unused-vars`
```javascript
/* src/app/test.jsx */
const a = 1;
```
1. Run `eslint` and `next lint` to the same file.
See screenshot below.
`eslint` command works correctly with absolute path. ***but,*** `next
lint` command doesn't work correctly with absolute path.
#### Code Details
```javascript
/* packages/next/src/cli/next-lint.ts */
// ...
const pathsToLint = (
filesToLint.length ? filesToLint : ESLINT_DEFAULT_DIRS
).reduce((res: string[], d: string) => {
const currDir = join(baseDir, d)
if (!existsSync(currDir)) {
return res
}
res.push(currDir)
return res
}, [])
// ...
```
**`pathsToLint`**
- `pathsToLint` gets an empty array `[]` when `filesToLint` array is `[
'D:\\Cloud_Git\\web-blog\\src\\app\\test.jsx' ]` passed by `--file`
option from CLI.
**The `reduce` Function**
- For each element (`d`) in `filesToLint`, it combines it with `baseDir`
to create `currDir`.
- It checks if this path exists using `existsSync(currDir)`.
- If the path does not exist, it does not add it to the resulting array
(`res`), and if it does exist, it adds it.
**Cause of the Issue**
- `join(baseDir, d)`:
- The `join` function is used to combine file paths and directory paths.
- If `baseDir` is `D:\Cloud_Git\web-blog`, then `currDir` becomes
`D:\Cloud_Git\web-blog\D:\Cloud_Git\web-blog\src\app\test.jsx`, creating
an incorrect path.
- `existsSync(currDir)`:
- With the incorrect path
(`D:\Cloud_Git\web-blog\D:\Cloud_Git\web-blog\src\app\test.jsx`),
`existsSync` determines that this path does not exist, so it does not
add it to the `res` array.
- As a result, `pathsToLint` ends up being an empty array `[]`.
### How? (Solution)
The code should be modified to use the file path as-is, without
combining it with `baseDir`. If a file path is provided, it should be
directly included in `pathsToLint`.
- Updated Path Handling: Modified the code that processes the `--file`
option to properly handle absolute paths. This involved ensuring that
absolute paths are correctly interpreted and used by the linting
command.
- Enhanced Compatibility with lint-staged: Adjusted the linting logic to
handle absolute paths returned by lint-staged, ensuring that linting
works as expected in automated workflows.
The code below is the built code of the modified version.
```javascript
/* node_modules/next/dist/cli/next-lint.js */
// ...
const pathsToLint = (filesToLint.length ? filesToLint : _constants.ESLINT_DEFAULT_DIRS).reduce((res, d)=>{
const currDir = (0, _fs.existsSync)(d) ? d : (0, _path.join)(baseDir, d);
if (!(0, _fs.existsSync)(currDir)) {
return res;
}
res.push(currDir);
return res;
}, []);
// ...
```
---
Closes: I tried to find but No related Issues.
Fixes: I tried to find but No related Issues.
---------
Co-authored-by: JJ Kasper <jj@jjsweb.site>
next.js
afcad43b - fix: ensure absolute paths are handled correctly with `--file` option in `next lint` command for `lint-staged` compatibility (#69220)
