Cannot modify token after login, i.e. for token refresh

[rhufsky]

Environment

  System:
    OS: macOS 15.1.1
    CPU: (8) arm64 Apple M1 Pro
    Memory: 1.34 GB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.12.0 - /opt/homebrew/opt/node@22/bin/node
    npm: 10.9.0 - /opt/homebrew/opt/node@22/bin/npm
    pnpm: 9.15.0 - /opt/homebrew/bin/pnpm
    bun: 1.1.40 - /opt/homebrew/bin/bun
  Browsers:
    Chrome: 131.0.6778.205
    Safari: 18.1.1
  npmPackages:
    next: 15.1.3 => 15.1.3 
    next-auth: ^5.0.0-beta.25 => 5.0.0-beta.25 
    react: ^19.0.0 => 19.0.0 ```


### Reproduction URL

http://localhost:3000

### Describe the issue

I have implemented authentication via the Gitlab Provider and that works fine.  I also want to refresh the access token whenever it has expired. My session strategy is `jwt`. This is my `jwt()` implementation:

async jwt({ token, user, account, profile }) {
  console.log(token);
  if (account && profile) {
    // First-time login, build the initial token
    token.gitlabUsername = profile?.username;

    if (user?.email?.endsWith(STUDENT_EMAIL_DOMAIN)) {
      const student = await getStudentByEmail(user.email);

      if (student?.clazz) {
        return { ...token, clazzName: student.clazz.name };
      }
      return token;
    } else {
      const dbUser = await getUserByUsername(
        token.gitlabUsername as string
      );

      return {
        ...token,
        roles: dbUser?.roles,
        access_token: account?.access_token,
        refresh_token: account?.refresh_token,
        expires_at: account?.expires_at,
      };
    }
  } else {
    // maybe we have to rwefresh the access_token and the refresh_token
    if (token.access_token) {
      try {
        // if there is an access token, check if it is still valid.
        const expirationDate = new Date(
          (token.expires_at as number) * 1000
        );

        if (expirationDate < new Date()) {
          logger.info("token expired, refresh token");

          const refreshResult = await refreshAccessToken(
            token.refresh_token as string
          );

          const rt = refreshResult as GitlabRefreshTokenResponse;


          if ("access_token" in refreshResult) {
           // ACCESS_TOKEN REFRESHED, store refreshed value in token and return it
            logger.info(`token refreshed`);
            return {
              ...token,
              access_token: rt.access_token,
              refresh_token: rt.refresh_token,
              expires_at: rt.expires_at,
              a_indicator: "TOKEN REFRESHED, JUST A DEBUGGING AID",
            };
          } else {
            logger.info(
              `error refreshing token: ${refreshResult.error} ${refreshResult.error_description}`
            );
            return token;
          }
        }
      } catch (error: unknown) {
        const e = error as Error;
        logger.info(`error refreshing token, ${e.message}`);
      }
    }
  }
  return token;
},

Whenever the access_token is refreshed, its new value plus the value of the refresh_token are added to the `token`and the `token`is returned.

On subsequent calls to `jwt()`, `token` has the original value as created after login.

### How to reproduce

Login, watch the value of `token`, wait for the refresh and watch the value again.

### Expected behavior

The returned token should be persisted in the JWT/Cookie and be available for further calls to `jwt()`. 

[github-actions]

We could not detect a valid reproduction link. Make sure to follow the bug report template carefully.

Why was this issue closed?

To be able to investigate, we need access to a reproduction to identify what triggered the issue. We need a link to a public GitHub repository. Example: (NextAuth.js example repository).

The bug template that you filled out has a section called "Reproduction URL", which is where you should provide the link to the reproduction.

• If you did not provide a link or the link you provided is not hosted on github.com outside of the next-auth organization, we will close the issue.
• If you provide a link to a private repository, we will close the issue.
• If you provide a link to a repository but not in the correct section, we will close the issue.

What should I do?

Depending on the reason the issue was closed, you can do the following:

• If you did not provide a link hosted on github.com outside of the next-auth organization, please open a new issue with a link to such a reproduction.
• If you provided a link to a private repository, please open a new issue with a link to a public repository.
• If you provided a link to a repository but not in the correct section, please open a new issue with a link to a reproduction in the correct section.

In general, assume that we should not go through a lengthy onboarding process at your company code only to be able to verify an issue.

My repository is private and cannot make it public

In most cases, a private repo will not be a sufficient minimal reproduction, as this codebase might contain a lot of unrelated parts that would make our investigation take longer. Please do not make it public. Instead, create a new repository using the templates above, adding the relevant code to reproduce the issue. Common things to look out for:

• Remove any code that is not related to the issue. (pages, API Routes, components, etc.)
• Remove any dependencies that are not related to the issue.
• Remove any third-party service that would require us to sign up for an account to reproduce the issue.
• Remove any environment variables that are not related to the issue.
• Remove private packages that we do not have access to.
• If the issue is not related to a monorepo specifically, try to reproduce the issue without a complex monorepo setup

I did not open this issue, but it is relevant to me, what can I do to help?

Anyone experiencing the same issue is welcome to provide a minimal reproduction following the above steps by opening a new issue.

I think my reproduction is good enough, why aren't you looking into it quickly?

We look into every issue and monitor open issues for new comments.

However, sometimes we might miss a few due to the popularity/high traffic of the repository. We apologize, and kindly ask you to refrain from tagging core maintainers, as that will usually not result in increased priority.

Upvoting issues to show your interest will help us prioritize and address them as quickly as possible. That said, every issue is important to us, and if an issue gets closed by accident, we encourage you to open a new one linking to the old issue and we will look into it.

Useful Resources

• How to create a Minimal, Complete, and Verifiable example
• Bug report: Framework
• Bug report: Provider
• Bug report: Adapter