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