Group README: Web IDE fails first commit on empty gitlab-profile (18.4.2-ee)

Summary

When creating a Group README via “Add README” in a newly created group, the Web IDE fails to commit the initial README.md.
The project gitlab-profile is created, but the repository remains empty because the first commit is not performed.

Steps to reproduce

  1. Create a new group (no projects inside).
  2. From the group page, click Add README.
  3. Web IDE opens with README.md ready to edit.
  4. Enter any content and click Commit to main branch.

Expected behavior

  • GitLab should create the hidden project gitlab-profile.
  • Branch main should be created automatically.
  • The first commit (README.md) should succeed.
  • Afterwards, the Group profile page shows the README.

Actual behavior

  • The project gitlab-profile is created, but remains empty (no branch).

  • Web IDE shows:

    Failed to commit changes. See the console for more information.

  • Server logs show:
    POST /api/v4/projects/:id/repository/commits … status:404 (commit not found)

Additional details

  • If the same commit is performed via API (POST /projects/:id/repository/files/README.md with branch=main), it works correctly.
  • If a project is created with “Initialize repository with a README”, the issue does not occur.
  • The problem happens only in the Group README workflow with an empty gitlab-profile repo.

System information

  • GitLab version: 18.4.2-ee (527e88bdddb)
  • GitLab Shell: 14.45.2
  • Ruby: 3.2.8
  • PostgreSQL: 16.10
  • Feature.get(:vscode_web_ide) => false
  • Installation: Omnibus, clean (no DB upgrade from previous version).

Workaround

Manually initializing README.md via API or CLI fixes the issue for that group.
After the first commit, Web IDE works fine.

Impact

  • Prevents using Add README at Group level on a fresh installation.
  • Confusing for users: the UI suggests it will work, but the commit always fails.
Edited by 🤖 GitLab Bot 🤖