Could not resolve dependency when upgrading from Next.js 14 to 15 RC

[tjhoo]

Summary

Hi,

I'm trying to follow the steps here to upgrade Next.js 14 to 15 RC and encounter the following error

$ npm install next@rc react@rc react-dom@rc
npm ERR! code ERESOLVE
npm ERR! ERESOLVE unable to resolve dependency tree
npm ERR!
npm ERR! While resolving: dummy@0.1.0
npm ERR! Found: react@19.0.0-rc-935180c7e0-20240524
npm ERR! node_modules/react
npm ERR!   react@"19.0.0-rc-935180c7e0-20240524" from the root project
npm ERR!
npm ERR! Could not resolve dependency:
npm ERR! peer react@"19.0.0-rc-f994737d14-20240522" from next@15.0.0-rc.0
npm ERR! node_modules/next
npm ERR!   next@"15.0.0-rc.0" from the root project
npm ERR!
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR!

is this an expected error and we should specify --force when installing the RC packages?

npm install --force next@rc react@rc react-dom@rc

Additional information

No response

Example

No response

[icyJoseph]

Hi,

The problem is that, https://github.com/vercel/next.js/blob/canary/packages/next/package.json#L108-L109, lists those RC specific versions, as peerDependencies.

Eventually, when React 19 does stabilize, this won't be a problem, but as release day approaches, and new react, react-dom RC versions are publishes, Next.js is bound to lag slightly behind.

[tjhoo]

Yes, and we have specify --force when upgrading to Next.js 15.

The command has to be fixed in the upgrade guide

[judygab]

Specifying --force didn't work for me either, I still got errors. Is there anything else you tried?

[stoufa88]

I tried upgrading a barebone next 14 app to 15 and it worked with --force. pnpm also worked for me while showing these warnings:

 WARN  Issues with peer dependencies found . └─┬ next 15.0.0-rc.0 ├── ✕ unmet peer react@19.0.0-rc-f994737d14-20240522: found 19.0.0-rc.0 └── ✕ unmet peer react-dom@19.0.0-rc-f994737d14-20240522: found 19.0.0-rc.0

[admintvalley]

same warning ┬ next 15.0.0-rc.0
├── ✕ unmet peer react@19.0.0-rc-f994737d14-20240522: found 19.0.0-rc-6230622a1a-20240610
└── ✕ unmet peer react-dom@19.0.0-rc-f994737d14-20240522: found 19.0.0-rc-6230622a1a-20240610

[gumpsh]

Has anyone managed to sort this yet? npm error code ERESOLVE
npm error ERESOLVE could not resolve
npm error
npm error While resolving: @heroicons/react@2.1.4
npm error Found: react@19.0.0-rc-6230622a1a-20240610
npm error node_modules/react
npm error react@"19.0.0-rc-6230622a1a-20240610" from the root project
npm error peer react@"19.0.0-rc-6230622a1a-20240610" from react-dom@19.0.0-rc-6230622a1a-20240610
npm error node_modules/react-dom
npm error react-dom@"19.0.0-rc-6230622a1a-20240610" from the root project
npm error 1 more (styled-jsx)
npm error
npm error Could not resolve dependency:
npm error peer react@">= 16" from @heroicons/react@2.1.4
npm error node_modules/@heroicons/react
npm error @heroicons/react@"^2.1.4" from the root project
npm error
npm error Conflicting peer dependency: react@18.3.1
npm error node_modules/react
npm error peer react@">= 16" from @heroicons/react@2.1.4
npm error node_modules/@heroicons/react
npm error @heroicons/react@"^2.1.4" from the root project
npm error
npm error Fix the upstream dependency conflict, or retry
npm error this command with --force or --legacy-peer-deps
npm error to accept an incorrect (and potentially broken) dependency resolution.
npm error
npm error
npm error For a full report see:

I have been trying all sorts of flags like --force, --legacy-peer-deps, -npm reinstall, --no-frozen-lockfile. I have also tried manually changing versions in the package.json, package-lock.json and yaml files. Nothing seems to work and my deployments are failing.

This is the dashboard project on the next.js getting started tutorial by the way.

I can launch the project from vscode and it all seems to run ok locally - but failing on the build I guess.

[icyJoseph]

Yeah, something along those lines. It didn't end there for me though. Once I had it all running, I had some type issues coming from 19 type changes, which are not very nice to fix 😅

[dusanbrankov]

I had the same problem yesterday and was able to solve it by adding the following to package.json:

  "overrides": {
    "some-dependency": {
      "react": "$react"
    }
  }

I had problems with drizzle-orm and react-hook-form, so my overrides directive looks like this:

  "overrides": {
    "drizzle-orm": {
      "react": "$react"
    },
    "react-hook-form": {
      "react": "$react"
    }
  }

Reference: drizzle-team/drizzle-orm#2251 (comment)

[o1Suleyman]

You don't have to be upgrading for these issues to arise. Correct me if I'm wrong, but I believe its because next have set the project up to use react 19c, but when to run npm install, some other dependencies in the project are not compatible with 19c. This is why bringing the react version back to a stable release version resolves the issue.

quite crazy to me coming from Java but otherwise I'm really enjoying Next

[icyJoseph]

Yeah, the React 19 release hit a major bump some months ago, and it has taken a bit to figure out a solution, plus it's implementation. Next 15 was kind of hoping that 19 would be out many months ago.

[gumpsh]

Npm dependencies - fun times! I've been developing a react native app in work and took a quick udemy course to learn the basics first. Anyway, a few months later I came back to the course to check something out and it just blew up everywhere after I decided to update the expo version. I then had to go through my dependencies in package.json to fix it. Expo was very good at telling me which dependencies to fix though and even told me which versions to update to.

[laurenmacam]

using pnpm this worked for me:
delete pnpm-lock.yaml file
run
pnpm up next@rc react@rc react-dom@rc eslint-config-next@rc
pnpm i

[gumpsh]

Hi @laurenmacam - thanks for your suggestion. I did try it, but still getting issues unfortunately.

However, I finally managed to solve it by downgrading from next, react and react-dom rc versions to latest stable releases.

It was a real mission, but all test are passing on the Vercel deployment now, so I am happy!

[jastka4]

Adding this to my package.json helped with all the issues I had:

  "overrides": {
    "next": {
      "react": "^19.0.0-rc-a960b92c-20240819",
      "react-dom": "^19.0.0-rc-a960b92c-20240819"
    }
  }

You might want to change the version to the latest React RC version.

[gumpsh]

Yeah, will definitely be upgrading to latest version as soon as everything catches up with it - which may be the case already for all I know - I've been doing other things for a while!

[bugplanter]

npm i next@rc react@rc react-dom@rc eslint-config-next@rc --legacy-peer-deps

[jdhiro]

There is a reason legacy-peer-deps are legacy. This is a bad practice.

You'd be better off creating an overrides section in your package.json to deal with specific version overrides.

[jdhiro]

Well I really want to upgrade, but I'm just taking this as a sign to wait until the next RC at least.

[RafaelZasas]

Dont do it. I'm in dependency hell atm. I just want to go home...

[gumpsh]

Is react 19 a stable release yet?