The Commits API does not return git trailers for individual commits

Everyone can contribute. Help move this issue forward while earning points, leveling up and collecting rewards.

• Close this issue

Summary

• The Commits API mentions support for git trailers
• Trailers are returned for the 'List repository commits' endpoint when ?trailers=true, but they are not populated on the 'Get a single commit' endpoint (nor are they mentioned in the example output 😅 )

Steps to reproduce

1. Create a commit for a repository using --trailer
2. For example: git commit -m "initial commit" --trailer "signed-off-by: testEmail@example.com"
3. Request the commits for the repository with ?trailers=true set. Example output:

  {
    "id": "d4a783e28b755b8873618d1091f4aa41ddf392f6",
    "short_id": "d4a783e2",
    "created_at": "2025-08-04T10:32:00.000+09:30",
    "parent_ids": [
      "cf66bfdef352225a96a4a1f3550a7cc4bd03f894"
    ],
    "title": "initial commit",
    "message": "initial commit\n\nsigned-off-by: testEmail@example.com\n",
    ....    
    "committer_email": "redacted@labgit",
    "committed_date": "2025-08-04T10:32:00.000+09:30",
    "trailers": {
      "signed-off-by": "testEmail@example.com"
    },
    "extended_trailers": {
      "signed-off-by": [
        "testEmail@example.com"
      ]
    },
   ....
]

3. Note that trailers and extended_trailers are populated.
4. Using the id for the commit, attempt to get a single commit (It does not appear to matter if ?trailers=true is appended):

{
  "id": "d4a783e28b755b8873618d1091f4aa41ddf392f6",
  "short_id": "d4a783e2",
  "created_at": "2025-08-04T10:32:00.000+09:30",
  "parent_ids": [
    "cf66bfdef352225a96a4a1f3550a7cc4bd03f894"
  ],
  "title": "initial commit",
  "message": "initial commit\n\nsigned-off-by: testEmail@example.com\n",
   ....  
  "authored_date": "2025-08-04T10:32:00.000+09:30",
  "committer_name": "Tom McAtee",
  "committer_email": "redacted@labgit",
  "committed_date": "2025-08-04T10:32:00.000+09:30",
  "trailers": {

  },
  "extended_trailers": {

  },
...
}

5. Observe that trailers and extended_trailers are not set

Example Project

• Internal-only: I have reproduced this behaviour in this sandbox project

What is the current bug behavior?

• The trailers/extended_trailers attributes are not populated on single commit API responses, but are populated on responses from the 'List repository commits' endpoint

What is the expected correct behavior?

• The trailers/extended_trailers attributes should be populated (when existent) on responses from both endpoints

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com

Possible fixes