monado/doc/changes

Usage of Proclamation to maintain changelogs

This file:

SPDX-License-Identifier: CC0-1.0
SPDX-FileCopyrightText: 2020 Collabora, Ltd. and the Proclamation contributors

This project uses the Proclamation tool to maintain changelogs. Contributors to this project do not need to use Proclamation, but they are asked to write a fragment for the changelog describing their change. See below for more details.

• Directory to run Proclamation in: doc/changes
  • Config file: default name (.proclamation.json)
• Location of the per-changelog-section directories: doc/changes

Table of Contents

• Quick Start Instructions for Contributors
• About Proclamation and Usage Instructions
  • Fragments
  • References
  • Sections
• Configuration
• Sample Usage Workflow
  • During Development
  • Preparing for a Release

Quick Start Instructions for Contributors

• Get a merge/pull request number for your change: this might involve pushing it as a WIP.
• Create a file in the appropriate section's directory, named mr.YOURNUMBER.md
• In that file, briefly describe your change as you would like it describe in the changelog for the next release.
• If your changes affect multiple sections, you can have a file in each section describing the section-specific changes.
• If your change resolves an issue or otherwise references some issue or merge/pull request, you can add those references to the beginning of your changelog fragment. See the full instructions below regarding References.

About Proclamation and Usage Instructions

The "Proclamation" tool assembles changelogs, which incorporate fragments of changelog text added by the author of a change in a specific location and format.

Fragments

Each change should add a changelog fragment file, whose contents are Markdown-formatted text describing the change briefly. Reference metadata will be used to automatically add links to associated issues/merge requests/pull requests, so no need to add these in your fragment text. The simplest changelog fragment just contains one line of Markdown text describing the change:

Here the author of a change has written some text about it.

(If you change the template in your Proclamation config file, your project can use a different markup format than Markdown.)

References

The changelog fragment system revolves around "references" - these are issue reports, pull requests, or merge requests associated with a change. Each fragment must have at least one of these, which forms the main part of the filename. If applicable, additional can be added within the file - see below for details.

This portion of the Proclamation system is intentionally left very flexible, since there are very many ways of organizing and managing a project. By default, references are delimited by the . character. The first two fields have some conventional meaning, while any additional fields are up to the user and are only used if a custom template is supplied by a project.

The format of references in general is:

<ref_type>.<number>

where

• ref_type is "issue", "mr", or "pr"
• number is the issue, MR, or PR number
• any additional .-delimited tokens are passed on to the template in the service_params list.

Your changelog fragment filename is simply the "main" reference with the .md extension added. (You can also use .rst or .txt as your extension in your project.)

To specify additional references in a file, prefix the contents of the changelog fragment with a block delimited above and below by ---, with one reference on each line. (This can be seen as a very minimal subset of "YAML Front Matter", if you're familiar with that concept.) For example:

---
- issue.35
- mr.93
---
Here the author of a change has written some text about it.

There are provisions for providing your own reference parser if this format is entirely unusable, but they're underdeveloped. (Most use cases found by the original author can actually be accommodated just by changing the template and specifying .-delimited fields in references.) If this functionality is interesting to you, get involved in the development of Proclamation and help finish it!

Sections

Changelog fragments are organized into sections, each of which should have its own directory. These might be "type-of-change" sections (e.g. new feature, bugfix, etc). Alternately, they might be logical sub-projects - it's permissible to have multiple projects configured in one config file and repo with partially-overlapping sections. (This is actually a part of one of the originally motivating use cases for this tool.)

Every file whose filename parses and meets some basic checks will be used! (You do need to add e.g. an .md file extension to files for them to parse as references.) Having a changes/your_section_name directory for each section is recommended. You can provide a README.md file with a modified subset of this file in that directory, as guidance to contributors to your project. (README.md won't parse as a reference, so it will not be treated as a changelog fragment.)

Use whatever works for your project. Right now, all changelog fragments must be in a section, sections must be a single directory, and sections may not be nested. If you'd like to loosen these assumptions, get involved in the development of Proclamation and help!

Configuration

Your project should have a configuration file: the default name is .proclamation.json. The top level object can either be a project config object directly, or contain a member named "projects" with an array of project config objects.

You can look at the config file for this project for guidance, since it's a pretty simple use case of this tool. (Proclamation was designed to handle more elaborate use-cases than this.)

• Project attributes:
  • project_name - Required. Used to form the heading in the default template, etc.
  • base_url - Technically optional, but required if you're using the default template. Passed to the template which may use it to form reference links.
  • news_filename - Optional, in case your changelog isn't called NEWS.
  • sections - Required: contains an object. The key names are the section names (used by the default template for section headers), while the values are objects. Sections might be logical sub-projects, or alternately categories of changes (feature, bug fix, etc), it's up to you.
    • The only key valid right now in the child of the section is directory, which indicates the directory to search for changelog fragments.
  • template - Optional. The name of a Jinja2 template for a single release's changelog section. base.md comes with Proclamation and is used by default. Your custom template might inherit from this if you only need to change a few small details. Evaluated relative to the current working directory when you run Proclamation.
  • insert_point_pattern - Useful mainly if you're not using the default template. The first match of this regex will be considered the first line of a release entry, and your new release will be put in your changelog file above it. Default works with the default template (looks for a second-level Markdown heading).
  • extra_data - Any extra data you'd like to pass along to your custom template.

Sample Usage Workflow

Note that the base proclamation script and all its subcommands have help, accessible through -h or --help. The guidance in this section of the README is intentionally minimal, to avoid contradicting the online help which remains up-to-date implicitly. This is also only the simplest, minimal way to perform these operations: if your project is more complex, there may already be more features to support your needs in the command line help.

During Development

As changes get submitted to your project, have each change author create a changelog fragment file. Since these are all separate files, with names made unique by your issue/repo tracker, there won't be merge conflicts no matter what order they're merged in. (This is the central benefit of Proclamation, and its inspiration, towncrier, over having each contributor edit CHANGES as part of their submission.)

At any time you can run proclamation draft to preview the release portion that would be added to your changelog if you released at that time.

Preparing for a Release

When you're ready to perform a release, you'll want to run Proclamation to update your changelog, then remove the fragments that you've incorporated into the regular changelog. You can use a command like the following:

proclamation build YOUR_NEW_VERSION

to preview the full file on screen. When you're ready to actually perform the update, run something like:

proclamation build YOUR_NEW_VERSION --delete-fragments --overwrite

to overwrite your changelog file with the updated one and delete the used changelog fragments.

You're welcome to manually edit the new (or old!) changelog entries as desired: as long as the insert_point_pattern (by default, ^## .*) can still match, Proclamation will not be confused.

Finally, make sure the deletion of the fragments and the update of the changelog has been checked in to your version control system.