Thank you for considering contributing to Swift-DocC.
Please know that everyone is welcome to contribute to Swift-DocC. Contributing doesn’t just mean submitting pull requests—there are many different ways for you to get involved, including answering questions on the Swift Forums, reporting or screening bugs, and writing documentation.
No matter how you want to get involved, we ask that you first learn what’s expected of anyone who participates in the project by reading the Swift Community Guidelines as well as our Code of Conduct.
This document focuses on how to contribute code and documentation to this repository.
By submitting a pull request, you represent that you have the right to license your
contribution to Apple and the community, and agree by submitting the patch that your
contributions are licensed under the Apache 2.0 license (see LICENSE.txt
).
Swift-DocC is an open source project and we encourage contributions from the community.
Before contributing code or documentation to Swift-DocC, we encourage you to first open a GitHub issue for a bug report or feature request. This will allow us to provide feedback on the proposed change. However, this is not a requirement. If your contribution is small in scope, feel free to open a PR without first creating an issue.
All changes to Swift-DocC source must go through the PR review process before
being merged into the main
branch.
See the Code Contribution Guidelines below for
more details.
docc
is the command line interface (CLI) for Swift-DocC and provides
support for generating and previewing documentation.
Swift-DocC is a Swift package. If you're new to Swift package manager, the documentation here provides an explanation of how to get started and the software you'll need installed.
-
Checkout this repository using:
git clone [email protected]:apple/swift-docc.git
-
Navigate to the root of your cloned repository with:
cd swift-docc
-
Create a new branch off of
main
for your change using:git checkout -b branch-name-here
Note that
main
(the repository's default branch) will always hold the most recent approved changes. In most cases, you should branch off ofmain
when starting your work and open a PR againstmain
when you're ready to merge that work. -
Build Swift-DocC from the command line by running:
swift build
Alternatively, to use Xcode, open the
Package.swift
file at the repository's root. Then, build it by pressing Command-B.
You can run your newly built version of docc
with:
swift run docc
Or, in Xcode, run the docc
scheme.
The JSON output of Swift-DocC is optimized for file size. If you need to inspect it
for debugging purposes set the DOCC_JSON_PRETTYPRINT
environment variable
to "YES" to enable pretty printing.
export DOCC_JSON_PRETTYPRINT="YES"
-
Do your best to keep the git history easy to understand.
-
Use informative commit titles and descriptions.
- Include a brief summary of changes as the first line.
- Describe everything that was added, removed, or changed, and why.
-
All changes must go through the pull request review process.
-
Follow the Swift API Design guidelines.
When you're ready to have your change reviewed, please make sure you've completed the following requirements:
-
Add tests to cover any new functionality or to prevent regressions of a bug fix.
-
Run the
/bin/test
script and confirm that the test suite passes. (See Testing Swift-DocC.) -
Add source code documentation to all added or modified APIs that explains the new behavior.
When opening a pull request, please make sure to fill out the pull request template and complete all tasks mentioned there.
Your PR should mention the number of the GitHub issue your work is addressing.
Most PRs should be against the main
branch. If your change is intended
for a specific release, you should also create a separate branch
that cherry-picks your commit onto the associated release branch.
All PRs will need approval from someone on the core team (someone with write access to the repository) before being merged.
All PRs must pass the required continuous integration tests as well. If you have commit access, you can run the required tests by commenting the following on your PR:
@swift-ci Please smoke test
If you do not have commit access, please ask one of the code owners to trigger them for you. For more details on Swift-DocC's continuous integration, see the Continous Integration section below.
We try to avoid source breaking changes, for example:
- removing or renaming public API
- adding protocol requirements to public API
- renaming Render JSON keys or adding new required Render JSON keys
That said, sometimes there are good reasons to make these changes. In those cases we make an effort to offer a backwards compatible transition by deprecating the old API, alongside the new API, and keeping the deprecated API for at least one full minor release. For example, if we deprecate an API sometime after the 5.5 release we keep the deprecated API for the remainder of the upcoming release (5.6) and the entirety of the next release (5.7).
To indicate to API consumers how long the deprecated API will be available, include the version when we'll remove that API in the deprecation message. For example:
@available(*, deprecated, message: "Use 'UpdatedSymbolName' instead. This deprecated API will be removed after 5.7 is released")
Swift-DocC is committed to maintaining a high level of code quality. Before opening a pull request, we ask that you:
-
Run the full test suite and confirm that it passes.
-
Write new tests to cover any changes you made.
The test suite can be run with the provided test
script
by navigating to the root of the repository and running the following:
bin/test
By running tests locally with the test
script you will be best prepared for
automated testing in CI as well.
You can test a locally built version of Swift-DocC in Xcode 13 or later by setting
the DOCC_EXEC
build setting to the path of your local docc
:
- Select the project in the Project Navigator.
- In the Build Settings tab, click '+' and then 'Add User-Defined Setting'.
- Create a build setting
DOCC_EXEC
with the value set to/path/to/docc
.
The next time you invoke a documentation build with the "Build Documentation"
button in Xcode's Product menu, your custom docc
will be used for the build.
You can confirm that your custom docc
is being used by opening the latest build
log in Xcode's report navigator and expanding the "Compile documentation" step.
Another option is to pass additional flags to the Swift compiler and invoking docc
directly.
The below instructions use this repository as an example but apply to any Swift package. Just
replace any reference to SwiftDocC
below with the name of your package.
Begin by navigating to the root of your Swift package.
cd ~/Developer/swift-docc
Then run the following to generate Symbol Graph files for your target:
mkdir -p .build/symbol-graphs && \
swift build --target SwiftDocC \
-Xswiftc -emit-symbol-graph \
-Xswiftc -emit-symbol-graph-dir -Xswiftc .build/symbol-graphs
You should now have a number of .symbols.json
files in .build/symbol-graphs
representing the provided target and its dependencies. You can copy out the files representing
just the target itself with:
mkdir .build/swift-docc-symbol-graphs \
&& mv .build/symbol-graphs/SwiftDocC* .build/swift-docc-symbol-graphs
The best place to get started with Swift-DocC-Render is with the instructions in the project's README.
If you have Xcode 13 or later installed, you can use the version of Swift-DocC-Render that comes included in Xcode with:
export DOCC_HTML_DIR="$(dirname $(xcrun --find docc))/../share/docc/render"
Alternatively, you can clone the Swift-DocC-Render-Artifact repository and use a recent pre-built copy of the renderer:
git clone https://github.com/swiftlang/swift-docc-render-artifact.git
Then point the DOCC_HTML_DIR
environment variable
to the repository's /dist
folder.
export DOCC_HTML_DIR="/path/to/swift-docc-render-artifact/dist"
The docc preview
command performs a conversion of your documentation and
starts a local web server to allow for easy previewing of the built documentation.
It monitors the provided documentation catalog for changes and updates the preview
as you're working.
swift run docc preview Sources/SwiftDocC/SwiftDocC.docc \
--fallback-display-name SwiftDocC \
--fallback-bundle-identifier org.swift.SwiftDocC \
--fallback-bundle-version 1.0.0 \
--additional-symbol-graph-dir .build/swift-docc-symbol-graphs
You should now see the following in your terminal:
Input: ~/Developer/swift-docc/Sources/SwiftDocC/SwiftDocC.docc
Template: ~/Developer/swift-docc-render-artifact/dist
========================================
Starting Local Preview Server
Address: http://localhost:8080/documentation/swiftdocc
========================================
Monitoring ~/Developer/swift-docc/Sources/SwiftDocC/SwiftDocC.docc for changes...
And if you navigate to http://localhost:8080/documentation/swiftdocc you'll see
the rendered documentation for SwiftDocC
.
Today, Swift-DocC supports both macOS and Linux. While most Swift APIs are cross-platform, there are some minor differences. Because of this, all PRs will be automatically tested in both macOS and Linux environments.
macOS users can test that their changes are compatible with Linux by running the test suite in a Docker environment that simulates Swift on Linux.
-
Install Docker Desktop for Mac.
-
Build Swift-DocC (see Building Swift-DocC).
-
Run the following command from the root of this repository to build the Swift-DocC Docker image:
docker build -t swift-docc:latest .
-
Run the following command to run the test suite:
docker run -v `pwd`:/swift-docc swift-docc sh -c 'swift test --package-path /swift-docc --parallel --skip-update'
-
To interactively test the command line interface, first log into the container with:
docker run -i -t -v `pwd`:/swift-docc swift-docc /bin/bash
And then run
docc
within the container:cd swift-docc swift run docc
Swift-DocC uses swift-ci infrastructure for its continuous integration testing. The tests can be triggered on pull-requests if you have commit access. If you do not have commit access, please ask one of the code owners to trigger them for you.
-
Smoke Test (required): Run the project's unit tests on macOS and Linux by commenting the following:
@swift-ci Please smoke test
This is required before a pull-request can be merged.
Platform specific instructions:
-
Run the project's unit tests on macOS by commenting the following:
@swift-ci Please smoke test macOS platform
-
Run the project's unit tests on Linux by commenting the following:
@swift-ci Please smoke test Linux platform
-
-
Test: Run the project's unit tests on macOS and Linux, along with a selection of compatibility suite tests on macOS by commenting the following:
@swift-ci Please test
Platform specific instructions:
-
Run the project's unit tests on macOS, along with a selection of compatibility suite tests by commenting the following:
@swift-ci Please test macOS platform
-
Run the project's unit tests on Linux by commenting the following:
@swift-ci Please test Linux platform
Note: This is equivalent to running smoke tests for the Linux platform.
-
-
Compatibility Test: Run the Swift compatibility suite tests in both Release and Debug configuration by commenting the following:
@swift-ci Please test source compatibility
Build configuration specific instructions:
-
Run the Swift compatibility suite tests in Release configuration by commenting the following:
@swift-ci Please test source compatibility Release
-
Run the Swift compatibility suite tests in Debug configuration by commenting the following:
@swift-ci Please test source compatibility Debug
-
-
Performance Smoke Test: Test compiler performance on macOS with a selection of Swift compatibility suite projects by commenting the following:
@swift-ci Please smoke test compiler performance
-
Performance Test: Test compiler performance on macOS with all Swift compatibility suite projects by commenting the following:
@swift-ci Please test compiler performance
Unsure of where to begin contributing to Swift-DocC? You can start by looking at the issues on the good first issue page.
Once you've found an issue to work on, follow the above instructions for Building Swift-DocC.
Swift-DocC builds documentation by combining Symbol Graph files that contains API information
with a .docc
documentation catalog that contains articles and tutorials
to create a final archive with the compiled documentation.
More concretely, Swift-DocC understands the following kinds of inputs:
-
Symbol Graph files with the
.symbols.json
extension. Symbol Graph files are a machine-readable representation of a module's APIs, including their documentation comments and relationship with one another. -
A documentation catalog directory with the
.docc
extension. Documentation catalogs can include additional documentation content like the following:
-
Documentation markup files with the
.md
extension. Documentation markup files can be used to write articles and to extend documentation for symbols. -
Tutorial files with the
.tutorial
extension. Tutorial files are used to author step-by-step instructions on how to use a framework. -
Additional documentation assets with known extensions like
.png
,.jpg
,.mov
, and.zip
. -
An
Info.plist
file containing metadata such as the name of the documented module. This file is optional and the information it contains can be passed via the command line.
Swift-DocC outputs a machine-readable archive of the compiled documentation. This archive contains render JSON files, which fully describe the contents of a documentation page and can be processed by a renderer such as Swift-DocC-Render.
For more in-depth technical information about Swift-DocC, please refer to the project's technical documentation:
-
As of Swift 5.5, the Swift Compiler is able to emit Symbol Graph files as part of the compilation process.
-
SymbolKit is a Swift package containing the specification and reference model for the Symbol Graph File Format.
-
Swift Markdown is a Swift package for parsing, building, editing, and analyzing Markdown documents. It includes support for the Block Directive elements that Swift-DocC's tutorial files rely on.
-
Swift-DocC-Render is a web application that understands and renders Swift-DocC's render JSON format.
-
Xcode consists of a suite of tools that developers use to build apps for Apple platforms. Beginning with Xcode 13, Swift-DocC is integrated into Xcode with support for building and viewing documentation for your framework and its dependencies.