Improve error message for inaccessible remote CI includes

Problem to Solve

When a GitLab CI configuration includes a remote file from a private project, the error message is misleading and doesn't clearly explain the actual issue.

In the documentation, we mention that: https://docs.gitlab.com/ci/yaml/#includeremote

A public URL accessible by an HTTP/HTTPS GET request:

Authentication with the remote URL is not supported.

Current Behavior

Users see a confusing YAML parsing error:

This GitLab CI configuration is invalid: 
mapping values are not allowed in this context at line 17 column 45

Expected Behavior

The error message should clearly state:

  • The remote URL is not accessible
  • Authentication is not supported for remote includes
  • The file must be publicly accessible via HTTP/HTTPS
  • Suggest alternatives (use include:local or make the project public/internal)

Root Cause

According to the documentation (https://docs.gitlab.com/ci/yaml/#includeremote):

A public URL accessible by an HTTP/HTTPS GET request. Authentication with the remote URL is not supported.

When GitLab tries to fetch a remote file from a private project, it receives a 401/403 response, but instead of reporting this clearly, it returns a generic YAML parsing error that misleads users into thinking their configuration syntax is wrong.

Example Scenario

  1. User has a private project with CI templates: https://gitlab.com/group/project/template-1.yml
  2. User tries to include it in another project:
include:
  remote: https://gitlab.com/group/project/.gitlab-ci-yml`
  1. GitLab returns: mapping values are not allowed in this context at line 17 column 45
Edited by Christopher Mutua