<!DOCTYPE HTML>
<html lang="en" class="navy sidebar-visible" dir="ltr">
<head>
<meta charset="UTF-8">
<title>Contributing - towl Documentation</title>
<meta name="description" content="Documentation for towl - a fast CLI tool to scan codebases for TODO comments">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="theme-color" content="#ffffff">
<link rel="icon" href="../favicon.svg">
<link rel="shortcut icon" href="../favicon.png">
<link rel="stylesheet" href="../css/variables.css">
<link rel="stylesheet" href="../css/general.css">
<link rel="stylesheet" href="../css/chrome.css">
<link rel="stylesheet" href="../css/print.css" media="print">
<link rel="stylesheet" href="../FontAwesome/css/font-awesome.css">
<link rel="stylesheet" href="../fonts/fonts.css">
<link rel="stylesheet" id="highlight-css" href="../highlight.css">
<link rel="stylesheet" id="tomorrow-night-css" href="../tomorrow-night.css">
<link rel="stylesheet" id="ayu-highlight-css" href="../ayu-highlight.css">
<script>
const path_to_root = "../";
const default_light_theme = "navy";
const default_dark_theme = "navy";
window.path_to_searchindex_js = "../searchindex.js";
</script>
<script src="../toc.js"></script>
</head>
<body>
<div id="mdbook-help-container">
<div id="mdbook-help-popup">
<h2 class="mdbook-help-title">Keyboard shortcuts</h2>
<div>
<p>Press <kbd>←</kbd> or <kbd>→</kbd> to navigate between chapters</p>
<p>Press <kbd>S</kbd> or <kbd>/</kbd> to search in the book</p>
<p>Press <kbd>?</kbd> to show this help</p>
<p>Press <kbd>Esc</kbd> to hide this help</p>
</div>
</div>
</div>
<div id="body-container">
<script>
try {
let theme = localStorage.getItem('mdbook-theme');
let sidebar = localStorage.getItem('mdbook-sidebar');
if (theme.startsWith('"') && theme.endsWith('"')) {
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
}
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
}
} catch (e) { }
</script>
<script>
const default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? default_dark_theme : default_light_theme;
let theme;
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
if (theme === null || theme === undefined) { theme = default_theme; }
const html = document.documentElement;
html.classList.remove('navy')
html.classList.add(theme);
html.classList.add("js");
</script>
<input type="checkbox" id="sidebar-toggle-anchor" class="hidden">
<script>
let sidebar = null;
const sidebar_toggle = document.getElementById("sidebar-toggle-anchor");
if (document.body.clientWidth >= 1080) {
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
sidebar = sidebar || 'visible';
} else {
sidebar = 'hidden';
sidebar_toggle.checked = false;
}
if (sidebar === 'visible') {
sidebar_toggle.checked = true;
} else {
html.classList.remove('sidebar-visible');
}
</script>
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
<mdbook-sidebar-scrollbox class="sidebar-scrollbox"></mdbook-sidebar-scrollbox>
<noscript>
<iframe class="sidebar-iframe-outer" src="../toc.html"></iframe>
</noscript>
<div id="sidebar-resize-handle" class="sidebar-resize-handle">
<div class="sidebar-resize-indicator"></div>
</div>
</nav>
<div id="page-wrapper" class="page-wrapper">
<div class="page">
<div id="menu-bar-hover-placeholder"></div>
<div id="menu-bar" class="menu-bar sticky">
<div class="left-buttons">
<label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
<i class="fa fa-bars"></i>
</label>
<button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
<i class="fa fa-paint-brush"></i>
</button>
<ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
<li role="none"><button role="menuitem" class="theme" id="default_theme">Auto</button></li>
<li role="none"><button role="menuitem" class="theme" id="light">Light</button></li>
<li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
<li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
<li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
<li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
</ul>
<button id="search-toggle" class="icon-button" type="button" title="Search (`/`)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="/ s" aria-controls="searchbar">
<i class="fa fa-search"></i>
</button>
</div>
<h1 class="menu-title">towl Documentation</h1>
<div class="right-buttons">
<a href="../print.html" title="Print this book" aria-label="Print this book">
<i id="print-button" class="fa fa-print"></i>
</a>
<a href="https://github.com/glottologist/towl" title="Git repository" aria-label="Git repository">
<i id="git-repository-button" class="fa fa-github"></i>
</a>
<a href="https://github.com/glottologist/towl/edit/main/docs/src/src/reference/contributing.md" title="Suggest an edit" aria-label="Suggest an edit" rel="edit">
<i id="git-edit-button" class="fa fa-edit"></i>
</a>
</div>
</div>
<div id="search-wrapper" class="hidden">
<form id="searchbar-outer" class="searchbar-outer">
<div class="search-wrapper">
<input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
<div class="spinner-wrapper">
<i class="fa fa-spinner fa-spin"></i>
</div>
</div>
</form>
<div id="searchresults-outer" class="searchresults-outer hidden">
<div id="searchresults-header" class="searchresults-header"></div>
<ul id="searchresults">
</ul>
</div>
</div>
<script>
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
});
</script>
<div id="content" class="content">
<main>
<h1 id="contributing"><a class="header" href="#contributing">Contributing</a></h1>
<h2 id="getting-started"><a class="header" href="#getting-started">Getting Started</a></h2>
<pre><code class="language-bash">git clone https://github.com/glottologist/towl.git
cd towl
cargo build
</code></pre>
<h3 id="requirements"><a class="header" href="#requirements">Requirements</a></h3>
<ul>
<li><strong>Rust</strong> 1.75+ (see <code>rust-toolchain.toml</code>)</li>
<li><strong>git</strong> on <code>PATH</code></li>
</ul>
<h2 id="development-commands"><a class="header" href="#development-commands">Development Commands</a></h2>
<pre><code class="language-bash"># Build
cargo build
# Run all tests
cargo nextest run # preferred
cargo test # fallback
# Clippy (strict)
cargo clippy --all-targets --all-features
# Format
cargo fmt
# Run the binary
cargo run -- scan
cargo run -- scan -f json -o todos.json
cargo run -- config
cargo run -- init
</code></pre>
<h2 id="project-structure"><a class="header" href="#project-structure">Project Structure</a></h2>
<p>See <a href="./architecture.html">Architecture</a> for a full layout. Key entry points:</p>
<ul>
<li><code>src/bin/towl.rs</code> -- CLI binary</li>
<li><code>src/lib/mod.rs</code> -- Library root</li>
<li><code>tests/</code> -- Integration and property-based tests</li>
</ul>
<h2 id="testing"><a class="header" href="#testing">Testing</a></h2>
<h3 id="test-hierarchy"><a class="header" href="#test-hierarchy">Test Hierarchy</a></h3>
<p>Tests follow a strict hierarchy:</p>
<ol>
<li><strong>proptest</strong> (property-based) -- First choice for pure functions, parsers, validators, serialisation roundtrips</li>
<li><strong>rstest</strong> (parameterized) -- For specific known cases (< 10 inputs with exact expected outputs)</li>
<li><strong>Standalone</strong> -- Last resort, for complex integration scenarios</li>
</ol>
<h3 id="running-tests"><a class="header" href="#running-tests">Running Tests</a></h3>
<pre><code class="language-bash"># All tests
cargo nextest run
# Specific module
cargo nextest run scanner
# Property-based tests only
cargo nextest run proptest
# Integration tests only
cargo nextest run --test '*'
</code></pre>
<h2 id="code-style"><a class="header" href="#code-style">Code Style</a></h2>
<ul>
<li>Follow Rust naming conventions (<code>snake_case</code> for functions, <code>CamelCase</code> for types)</li>
<li>All public items need doc comments (<code>///</code>)</li>
<li>No <code>#[allow(...)]</code> attributes -- fix the underlying issue</li>
<li>No <code>.unwrap()</code> / <code>.expect()</code> in production code -- use <code>?</code> with typed errors</li>
<li>No <code>as</code> numeric casts -- use <code>try_from</code> / <code>into</code> / <code>From</code></li>
<li>Minimise <code>.clone()</code> -- prefer borrowing, see Clone Reduction Policy</li>
</ul>
<h2 id="error-handling"><a class="header" href="#error-handling">Error Handling</a></h2>
<ul>
<li>Use <code>thiserror</code> for error type derivation</li>
<li>Each module defines its own error enum</li>
<li>Errors propagate upward via <code>?</code> and <code>#[from]</code></li>
<li>Never silently discard <code>Result</code> values</li>
</ul>
<h2 id="adding-a-new-output-format"><a class="header" href="#adding-a-new-output-format">Adding a New Output Format</a></h2>
<ol>
<li>Create <code>src/lib/output/formatter/formatters/yourformat.rs</code></li>
<li>Implement the <code>Formatter</code> trait</li>
<li>Add a variant to <code>FormatterImpl</code> in <code>formatters/mod.rs</code></li>
<li>Add dispatch in <code>FormatterImpl::format()</code></li>
<li>Add a variant to <code>OutputFormat</code> in <code>src/lib/cli/mod.rs</code></li>
<li>Update the format-to-writer mapping in <code>Output::new()</code></li>
<li>Add tests (proptest for roundtrips, rstest for edge cases)</li>
</ol>
<h2 id="adding-a-new-todo-type"><a class="header" href="#adding-a-new-todo-type">Adding a New TODO Type</a></h2>
<ol>
<li>Add a variant to <code>TodoType</code> in <code>src/lib/comment/todo.rs</code></li>
<li>Update <code>Display</code>, <code>TryFrom<&str></code>, <code>as_filter_str()</code></li>
<li>Add a default pattern to <code>default_todo_patterns()</code> in <code>src/lib/config/types.rs</code></li>
<li>Add a pattern mapping in the parser</li>
<li>Update tests</li>
</ol>
<h2 id="pull-requests"><a class="header" href="#pull-requests">Pull Requests</a></h2>
<ul>
<li>Keep PRs focused on a single change</li>
<li>Include tests for new functionality</li>
<li>Ensure <code>cargo clippy</code> passes with zero warnings</li>
<li>Ensure <code>cargo fmt</code> produces no changes</li>
<li>Ensure all tests pass</li>
</ul>
</main>
<nav class="nav-wrapper" aria-label="Page navigation">
<a rel="prev" href="../reference/ci-cd.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
<i class="fa fa-angle-left"></i>
</a>
<div style="clear: both"></div>
</nav>
</div>
</div>
<nav class="nav-wide-wrapper" aria-label="Page navigation">
<a rel="prev" href="../reference/ci-cd.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
<i class="fa fa-angle-left"></i>
</a>
</nav>
</div>
<script>
window.playground_copyable = true;
</script>
<script src="../elasticlunr.min.js"></script>
<script src="../mark.min.js"></script>
<script src="../searcher.js"></script>
<script src="../clipboard.min.js"></script>
<script src="../highlight.js"></script>
<script src="../book.js"></script>
</div>
</body>
</html>