Here I provide a high level description of the functionality I am working towards. To set achievable goals, milestones will be rather small and the functionality I aim for may appear incomplete.

Domain Terms are shown in bold. For a list of DDD terms, see

Current milestone (#1)

Create the Fix command line application that provides basic functionality for issues. As storage use a single JSON file, located in a .fix subdirectory of the working directory.

An issue is an aggregate with the follwing values:

  • The title is a string of restricted length (6-120 characters) and character set (alphanumeric, space, punctuation without backspace and backtick)
  • The description is a unicode string, length theoretically unlimited (limited by storage format and other technical boundaries)
  • The issue ID is a string that is set when the issue is created and can never be changed. To avoid conflicts when Fix is used with Git (see here), consecutive numbers can not be used. Instead, an issue ID has a special format aaa-bbb-ccc-ddd-xxxxxxx: four blocks of 2-3 alphanumeric characters each, and a block of 7 hexadecimal characters. Blocks are separated by hyphens.
  • The status for now can have two possible values: open and closed

For this first milestone, I want to be able to do the following:

  • create an issue: This command creates a new issue and stores it in the issue repository. The title and description are parameters of the command, the status is open. The issue ID is generated by abbreviating the first four words of the title (if there are as many) and a hash of the title and description.
  • set the status: This command changes the status of an issue to one of the two allowed values (see above).
  • list all existing issues: This query shows a list (no specific order) of all issues with their issue ID, titles, and status. Titles may be abbreviated to fit on a single line.
  • show a single issue: This query shows the title, status, and description of the issue with the given issue ID

Out of scope:

  • deletion of issues is not that important for now
  • editing of description and title should come soon, but not now
  • explicitly setting the issue ID (or part of it) may be a desirable feature for some future milestone
  • more fields for issues, like tags, comments, etc.
  • more allowed values for status


  • 2021-08-13: issue IDs are all lower case (prefix and hash)
  • 2021-08-20: titles are further restricted to printable ASCII characters (except backspace and backtick)