What

This script migrates milestones, issues/tickets, and wiki pages from Trac to GitHub.

The script has its origin at https://github.com/moimael/trac-to-gitlab,
which then was extended to suite a specific use case of SVN+Trac to GitLab migration.
Next, GitLab specific code was removed, and a migration to GitHub was added.

In its present form, it is used for the migration of SageMath from
https://trac.sagemath.org/ to GitHub. This migration is described in more detail in
https://trac.sagemath.org/ticket/30363

Why

docs/Github-vs-Gitlab-vs-trac.md compares
Github and Trac,
focusing on the specific differences that are important to the SageMath
community.

How

Migrating a Trac project to GitHub is a relatively complex process involving four steps:

• Create a new project
• Migrate the repository
• Migrate issues and milestones
• Migrate wiki pages

The script migrate.py takes care of the third and fourth bullet points.

Usage:

1. Symlink or copy migrate.cfg.sagetracmigrationarchive to migrate.cfg
2. Configure the values
3. Run (./migrate.py).

See docs/Migration-Trac-to-Github.md for details of the migration process
and a proposed workflow on GitHub (with transition guide from Trac for developers).

Features

• Creates a migration archive
  in a subdirectory archive/, containing records for issues (converted from Trac tickets).
• Creates a markdown file for each converted ticket for easy inspection of the generated migration archive
  in subdirectories of wiki/ like Issues-33xxx.
• Ticket title, description, comments, attachments are copied over.
• Component, issue type, priority, severity, resolution are converted to labels.
• Selected keywords and milestones can be converted to labels.
• CC is added to the issue description as “@” mentions.
• Attribute changes are converted to issue events or issue comments.
• Creates a file minimized_issue_comments.json that lists the IDs of issue comments that
  correspond to attribute changes.
• Links to the cgit server are rewritten as GitHub repository links.
• Links to Trac tickets and ticket comments are rewritten as GitHub issue links.
• Links to the Trac wiki are rewritten as GitHub wiki links.
• Wiki pages including attachments are exported into files in wiki/ that can be
  added to the GitHub project wiki repository.

Missing

• History on wiki pages is not kept.
• Edit history of ticket comments is not kept.

Other modes of operation of the script (not used in the SageMath migration)

Instead of creating a migration archive, the script can directly add issues to a GitHub project.
See migrate.cfg.example for a sample configuration for this mode of operation.

• It needs either a GitHub access token or a username/password pair.
• All issues and issue comments are attributed to this username, and timestamps are not preserved.
• Original usernames and timestamps are noted as part of the Issue descriptions and comments.
• Make sure you test it on a test project prior; if you run the script twice against the same project,
  you will get duplicated issues.
• Issue text attachments are uploaded as Gist (GitHub doesn’t allow to attach files to issues via the GitHub API)
  or all issue attachments are exported to local files

License

LGPL license version 3.0.

Requirements

• Python 3; various packages, see requirements.txt
• Trac server on which XML-RPC plugin enabled