Drupal Coding Standards

Apply Drupal coding standards based on the development context.

Core Principles

From

coding_standards/index.md

:

• All code must follow Drupal coding standards (version-independent)
• Use US English spelling in all comments and names
• Standards are "always-current" and apply to all new code
• Follow Boy Scout Rule: leave code better than you found it

Context Detection & Standard Loading

PHP Development (.php files, modules, services, plugins)

When working with PHP code, ALWAYS read these standards FIRST:

1. Core Standards: Read

   coding_standards/php/coding.md

2. Documentation: Read

   coding_standards/php/documentation.md

3. Namespaces: Read

   coding_standards/php/namespaces.md

4. PSR-4: Read

   coding_standards/php/psr4.md

Additionally, based on specific needs:

• Creating services → Read

  coding_standards/php/naming-services.md

• Exception handling → Read

  coding_standards/php/exceptions.md

• Using placeholders → Read

  coding_standards/php/placeholders-delimiters.md

• Error handling → Read

  coding_standards/php/e_all.md

• Documentation examples → Read

  coding_standards/php/documentation-examples.md

JavaScript Development (.js files)

ALWAYS read these standards FIRST:

1. Core Standards: Read

   coding_standards/javascript/coding.md

2. Documentation: Read

   coding_standards/javascript/documentation.md

3. Best Practices: Read

   coding_standards/javascript/best-practice.md

4. ESLint Config: Read

   coding_standards/javascript/eslint.md

If using jQuery:

• Read

  coding_standards/javascript/jquery.md

CSS Development (.css, .scss files, styling)

ALWAYS read these standards FIRST:

1. Core Standards: Read

   coding_standards/css/coding.md

2. Formatting: Read

   coding_standards/css/format.md

3. File Organization: Read

   coding_standards/css/file-organization.md

4. Architecture: Read

   coding_standards/css/architecture.md

For tool configuration:

• Read

  coding_standards/css/csscomb.md

• Read

  coding_standards/css/review.md

SQL Queries (database operations)

ALWAYS read these standards FIRST:

1. Conventions: Read

   coding_standards/sql/conventions.md

2. Keywords: Read

   coding_standards/sql/keywords.md

3. SELECT Queries: Read

   coding_standards/sql/select-from.md

Twig Templates (.twig files)

ALWAYS read these standards:

1. Twig Standards: Read

   coding_standards/twig/coding.md

2. Markup Standards: Read

   coding_standards/markup/style.md

YAML Configuration (.yml, .yaml files)

ALWAYS read:

• Read

  coding_standards/yaml/configuration-files.md

Composer Packages (composer.json)

ALWAYS read:

• Read

  coding_standards/composer/package-name.md

Accessibility (forms, UI components, interactive elements)

ALWAYS read:

• Read

  coding_standards/accessibility/accessibility.md

Spelling & General

ALWAYS apply:

• Read

  coding_standards/spelling/spelling.md

  (US English required)

Workflow

1. User requests development task
   ↓
2. Identify file types/context (PHP, JS, CSS, SQL, etc.)
   ↓
3. Read ALL relevant standard files from coding_standards/
   ↓
4. Apply standards while writing code
   ↓
5. Validate code against standards
   ↓
6. Complete task with compliant code

Multi-Context Tasks

For tasks involving multiple file types, load ALL relevant standards:

Example: Creating a custom module

• PHP standards (module code)
• JavaScript standards (if includes JS)
• CSS standards (if includes styling)
• Twig standards (if includes templates)
• YAML standards (for .info.yml and config files)
• Accessibility standards (if includes UI)

Application Rules

1. Read First, Write Second: Always read relevant standards before generating code
2. No Assumptions: Never assume standards—always verify from files
3. Exact Compliance: Follow standards exactly as written
4. US English Only: All comments, variable names, and documentation
5. Complete Coverage: If working with multiple file types, apply all relevant standards
6. Validation: Before completing, verify code against loaded standards

Examples

Example 1: Creating a PHP Service

User: "Create a service to handle user notifications"

Actions:
1. Identify: PHP service development
2. Read standards:
   - coding_standards/php/coding.md
   - coding_standards/php/documentation.md
   - coding_standards/php/namespaces.md
   - coding_standards/php/naming-services.md
3. Generate code following all standards
4. Include proper docblocks, namespaces, service naming

Example 2: Writing Database Query

User: "Write a query to get active users with roles"

Actions:
1. Identify: SQL query
2. Read standards:
   - coding_standards/sql/conventions.md
   - coding_standards/sql/keywords.md
   - coding_standards/sql/select-from.md
3. Write query with proper keyword capitalization and formatting

Example 3: Building an Accessible Form

User: "Create a contact form with validation"

Actions:
1. Identify: Multi-context (PHP form API, JavaScript validation, accessibility)
2. Read standards:
   - coding_standards/php/coding.md
   - coding_standards/php/documentation.md
   - coding_standards/javascript/coding.md
   - coding_standards/markup/style.md
   - coding_standards/accessibility/accessibility.md
3. Build form with all standards applied
4. Ensure full accessibility compliance

Critical Reminders

• Never skip reading standards - always load them before coding
• Standards override preferences - follow Drupal standards exactly
• When uncertain - read additional related standard files
• Multi-file tasks - load standards for ALL file types involved
• US English spelling - non-negotiable requirement