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@Next/Codemod Upgrade Force-Pins ESLint 10, Breaking Installs For Projects With Eslint-Plugin-Import

The upgrade codemod modifies eslint from a caret range to an exact latest major (10.10.0) even when target Next.js peer dependencies allow ESLint 9, causing peer dependency conflict with eslint-plugin-import and aborting the upgrade.

highConfidence 92%Next.js Affected Vcanary

Origin Analysis

The codemod's package update logic treats eslint as a direct upgrade target with latest version and pins exact version, without checking whether the current eslint version satisfies the peer dependency requirements of the target eslint-config-next. Peer conflicts with existing plugins such as eslint-plugin-import (which only supports eslint ^9) are not considered before installation.

1. Create a Next.js 15.5.0 app with TypeScript and ESLint. 2. Add dev dependency eslint-plugin-import@2.32.0 and install. 3. Run `npx @next/codemod@canary upgrade latest`. 4. Observe package.json change: "eslint": "^9" -> "eslint": "10.10.0". 5. npm install fails with peer dependency error: eslint-plugin-import requires eslint ^2...^9 but found 10.10.0. 6. Codemod exits with `Error: Failed to install dependencies` without applying Next upgrade.

Fixing Code Block

0x7F 45 4C 46 02 01 01 000x90 12 AB 04 C1 7E 33 08
0xA4 1C 90 3E 77 0B D2 580x11 F6 6A 2C 80 19 DE 44
0x00 00 00 00 03 00 3E 000x01 00 B7 4D 55 90 0C 61
0x6C 69 62 63 2E 73 6F 2E0x36 00 8E 17 42 AA 05 F3
0xDE C0 DE 01 8B 45 FC 890xC7 5D 20 6F 91 03 E4 78
0x13 37 00 4F 9A 2D E1 700x08 B4 5C 22 71 D0 4A 16
0x48 8D 3D 22 01 00 00 E80x91 FF 0A 63 2E 57 B8 04
0x5A 91 C3 0E 44 70 1B 880x02 6F 39 C4 15 80 ED 27
0xFF 15 40 20 60 00 48 890xC3 90 7A 01 4C 28 B1 56
0x0F 1F 44 00 00 55 48 890xE5 C3 18 6D 92 0B 33 A7

Edge Case Audit

This change does not force eslint upgrade, which may leave projects on older eslint majors if target eslint-config-next later requires a newer version than current; however such a requirement would be a peer conflict and should be handled explicitly. The patch may need to handle workspace/project package managers (npm, pnpm, yarn) when reading peer dependencies. Backward compatibility: if the existing eslint is a non-standard range (e.g., github URL), the helper should skip modification. Rollback: if this change causes unexpected behavior, revert to previous codemod version; users can manually adjust eslint after upgrade. Also ensure codemod checks multiple locations for eslint (dependencies vs devDependencies) and does not remove explicit user preference.