= Contributing Code
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// Aliases:
:project-name: Asciidoctor PDF
:project-handle: asciidoctor-pdf
// URLs:
:url-asciidoctor: http://asciidoctor.org
:url-project: https://github.com/asciidoctor/asciidoctor-pdf
:url-project-repo: {url-project}
:url-project-issues: {url-project-repo}/issues
:url-project-chat: https://asciidoctor.zulipchat.com
:url-rvm: http://rvm.io

This guide provides all the information you need to become a successful Asciidoctor PDF developer and code contributor!
You'll learn how to retrieve the code from GitHub, execute the tests, build and install the gem, and run the application with your local modifications.

toc::[]

== Guidelines

To contribute code, fork the project on GitHub, hack away, and send a pull request with your proposed changes.
*All pull requests must include a) tests that verify the code change and b) an entry in the CHANGELOG.adoc file to document what changed.*
If a pull request is missing tests or a CHANGELOG entry, *it will not be merged* and may be closed.

Feel free to share ideas in the *#users/asciidoctor-pdf* stream of the {url-project-chat}[project chat] or report issues in the {url-project-issues}[issue tracker].

IMPORTANT: When filing an issue, you must include the AsciiDoc source and theme file (if relevant) that demonstrates the problem.
Sharing a screenshot of the output is not sufficient information to reproduce the issue and therefore not actionable.
If the AsciiDoc source is not provided within 24 hours of filing the issue, the issue will be closed.
A reproducible test case is required (in any form you can provide it) so we can concentrate our time on fixing the problem instead of trying to reverse engineer the scenario.

Follow the instructions below to learn how to clone the source and run it from your local copy.

== Development

=== Prerequisites

In order to set up the project build and run the tests, you'll need the following software installed on your computer:

* git
* Base development tools (for installing certain development gems)
* Ruby (with development headers)
* Bundler (optional, but recommended)
* pdftocairo (required for visual tests)

The test suite relies on additional software to analyze and assert the behavior of Asciidoctor PDF.
Therefore, these prerequisites are more extensive than what's needed for using Asciidoctor PDF alone.

If you're running a Debian-based Linux distribution, you can install the required software using the following command:

 $ sudo apt-get install -y build-essential git ruby-dev ruby-bundler poppler-utils

If you're running a Fedora-based Linux distribution, you can install the required software using the following command:

 $ sudo dnf group install -y "Development Tools"
   sudo dnf install -y redhat-rpm-config ruby-devel rubygem-bundler poppler-utils

If you want to run the tests on Fedora without using Bundler, install these dependencies instead:

 $ sudo dnf install -y ruby rubygem-asciidoctor rubygem-chunky_png rubygem-coderay rubygem-pdf-inspector \
   rubygem-prawn rubygem-prawn-icon rubygem-prawn-svg rubygem-prawn-table rubygem-prawn-templates \
   rubygem-rouge rubygem-rspec rubygem-treetop poppler-utils

You can study the CI workflow at [.path]_.github/workflows/ci.yml_ to learn more about what software is needed to run the full test suite.

=== Retrieve the Source Code

You can retrieve the source of {project-name} in one of two ways:

. Clone the git repository
. Download a zip archive of the repository

==== Option 1: Fetch Using Git

If you want to clone the git repository, copy the {url-project-repo}[GitHub repository URL] and pass it to the `git clone` command:

 $ git clone https://github.com/asciidoctor/asciidoctor-pdf

Next, change to the project directory:

 $ cd asciidoctor-pdf

==== Option 2: Download the Archive

If you want to download a zip archive, click the btn:[Download Zip] button on the right-hand side of the repository page on GitHub.
Once the download finishes, extract the archive, open a console and change to that directory.

TIP: Instead of working out of the {project-handle} directory, you can add the absolute path of the [path]_bin_ directory to your `PATH` environment variable.

We'll leverage the project configuration to install the necessary dependencies.

=== Install Dependencies

We recommend using {url-rvm}[RVM] to manage the installation of Ruby you'll use to build and develop the project.

 $ rvm use 3.1

The dependencies needed to use {project-name} are defined in the [.path]_Gemfile_ at the root of the project.
You can use Bundler to install the dependencies listed there.

To check you have Bundler available, use the `bundle` command to query the installed version:

 $ bundle version

If the `bundle` command is not available, use the `gem` command to install it.

 $ gem install bundler

Now configure Bundler to install the project dependencies within the project and run it:

 $ bundle config --local path .bundle/gems
   bundle

NOTE: You must call `bundle` from the project directory so that it can find the [.path]_Gemfile_.

=== Run the Tests

Tests are written using RSpec.
To run the tests, invoke rspec via bundler.

 $ bundle exec rspec

TIP: If you're using Ruby 2.7, you may have to turn off deprecation warnings using `export RUBYOPT='-W:no-deprecated'` in order for all of the tests to pass.

To disable tests that access the network, pass the `-t ~network` option:

 $ bundle exec rspec -t ~network

Similarly, to disable the visual integration tests, pass the `-t ~visual` option:

 $ bundle exec rspec -t ~visual

If a visual integration test fails, you can instruct the test suite to keep the files in the [.path]_spec/output_ directory by setting the `DEBUG` environment variable:

 $ DEBUG=true bundle exec rspec -t visual

If you want to see the name of each test as it is run, add the `-fd` option:

 $ bundle exec rspec -fd

You can also use the provided Rake task (note the name difference):

 $ bundle exec rake spec

Running tests using `rspec` directly gives you the advantage of being able to specify additional options.

To run a single test, you can filter by the name of the test.
For example, to run all tests that pertain to failures, use:

 $ bundle exec rspec -e fail

To run all tests that have `wip` in the name, use:

 $ bundle exec rspec -e wip

You can also run all tests in a given file by passing the file's path to rspec:

 $ bundle exec rspec spec/toc_spec.rb

For a full list of options that rspec provides, run `rspec -h`.

=== Run the Application (optional)

Like with Bundler, you have to run the application from the project directory.
Assuming all the required gems install properly, verify you can run the `asciidoctor-pdf` script using Ruby:

 $ bundle exec asciidoctor-pdf -v

If you see the version of {project-name} printed, you're ready to use {project-name}!

You can use the application to convert a document as follows:

 $ bundle exec asciidoctor-pdf /path/to/sample.adoc

=== Install the Application (optional)

If you want to install the application globally so you can run it anywhere, use the following `rake` task:

 $ bundle exec rake install

This task will package the gem and install it into your system gems.

If you want to install the gem using a separate command, first use the following `rake` task to build it:

 $ rm -rf pkg
   bundle exec rake build

This task packages the application as a gem and writes it to the [.path]_pkg_ directory.
A message will be printed to the console telling you the exact filename.
You can now use the `gem install` command to install it.

 $ gem install pkg/*.gem

You'll want to pay attention to which Ruby installation you are installing the gem into.
If successful, the `asciidoctor-pdf` executable will be available on your PATH.

TIP: If you're running {project-name} in a Gradle build, follow https://github.com/asciidoctor/asciidoctor-pdf/issues/650#issuecomment-258338060[these instructions] to use the development version of {project-name}.

=== Test a Pull Request

To test a pull request (PR), you first need to fetch the branch that contains the change and switch to it.
The steps below are covered in detail in the https://help.github.com/articles/checking-out-pull-requests-locally[GitHub help].

Let's assume you want to test PR 955.
Here's how you fetch and switch to it:

 $ git fetch origin pull/955/head:pr-955-review
   git checkout pr-955-review

IMPORTANT: Make sure you replace the number with the number of the PR you want to test.

In case any dependencies have changed, you should run the `bundle` command again:

 $ bundle

Now you can run the application as modified by the PR:

 $ bundle exec asciidoctor-pdf /path/to/sample.adoc

To switch back to main type:

 $ git checkout main

==== In Your Application

If you're using {project-name} in your application, you can test against the code in the pull request using Bundler.

First, you need to find the origin URL and branch of the PR.
You can find this information on the PR page.

Next, update the entry in your project's [.path]_Gemfile_ to point to the branch from which the pull request was originated.

.Gemfile
[source,ruby]
----
source 'https://rubygems.org'

gem 'asciidoctor-pdf', github: '<username>/asciidoctor-pdf', branch: 'issue-864'
----

Then run Bundler to update the gems in your project:

 $ rm -f Gemfile.lock
   bundle config --local github.https true
   bundle --path=.bundle/gems --binstubs=.bundle/.bin

Now you can run the development version of {project-name} using:

 $ bundle exec asciidoctor-pdf input.adoc

or

 $ ./.bundle/.bin/asciidoctor-pdf input.adoc

These instructions work for testing any development version of {project-name} directly from GitHub.

=== Run the Code Linter

Before you commit code, you should run it through the linter to make sure it adheres to the coding style.
You can run the linter using the following command:

 $ bundle exec rake lint

The coding style is enforced by https://rubocop.org/[RuboCop].
The rules are defined in [.path]_.rubocop.yml_.
These rules extend from the default rule set to match the style of the project.

In additional to those rules, the following rules are enforced manually:

* use tap/each instead of each_with_object to build a new Hash from an enumerable object

=== Generate Code Coverage Report

To generate a code coverage report when running tests using simplecov, set the `COVERAGE` environment variable as follows when running the tests:

 $ COVERAGE=true bundle exec rake spec

You'll see a total coverage score as well as a link to the HTML report in the output.
The HTML report helps you understand which lines and branches were missed, if any.

Despite being fast, the downside of using simplecov is that it misses code branches.
You can use deep-cover instead of simplecov to generate a more thorough report.
To do so, first run `bundle` at least once with the `COVERAGE` environment variable set:

 $ COVERAGE=true bundle

Then, set the `COVERAGE` environment variable to `deep` when running the tests:

 $ COVERAGE=deep bundle exec rake spec

You'll see a total coverage score, a detailed coverage report, and a link to HTML report in the output.
The HTML report helps you understand which lines and branches were missed, if any.

////
As an alternative to deep cover's native HTML reporter, you can also use istanbul / nyc.
First, you'll need to have the `nyc` command available on your system:

 $ npm install -g nyc

Next, in addition to the `COVERAGE` environment variable, also set the `DEEP_COVER_REPORTER` environment variable as follows when running the tests:

 $ COVERAGE=deep DEEP_COVER_REPORTER=istanbul bundle exec rake spec

You'll see a total coverage score, a detailed coverage report, and a link to HTML report in the output.
The HTML report helps you understand which lines and branches were missed, if any.
////

=== Rebuild the Formatter Text Parser

The formatted text is first converted to a pseudo-HTML language, then converted from there into Prawn text fragments using a https://github.com/cjheath/treetop[treetop] parser.
treetop is a Ruby-based parsing DSL based on parsing expression grammars.
This strategy allows the converter to manipulate the formatted text without needing the know the internal details of how Prawn arranges text fragments.
It also allows Asciidoctor to behave in a consistent manner, since some of the inline parsing in Asciidoctor assumes that the converter is generating an SGML-based language like HTML or DocBook.

The parsing expression grammar is defined in the source file [.path]_lib/asciidoctor/pdf/formatted_text/parser.treetop_.
If you make a change to this file, you must regenerate the parser, which is defined in the source file _lib/asciidoctor/pdf/formatted_text/parser.rb_.
(Don't modify the generated parser directly).

Use the following command to regenerate the parser:

 bundle exec tt lib/asciidoctor/pdf/formatted_text/parser.treetop

Then look for any places that a type is mixed into an object multiple times and remove the duplicate.
Finally, you then need to commit both files.
