Review Droid Guidelines are targeted instructions that Review Droid follows when reviewing your code. These guidelines ensure that Droid-provided code review comments are desirable, consistent, and specific to your codebase. They are particularly useful for maintaining code quality and enforcing best practices across a project.

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Configuring Guidelines

Guidelines are configured in your .droid.yaml file under the guidelines field within the review section. This configuration allows you to define different instructions based on file paths, ensuring that the guidelines are contextually relevant.

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Basic Structure

Here’s an example of how guidelines are structured in the .droid.yaml file: 
review:
  guidelines:
    - path: "src/*.py"
      guideline: "Do not use multi-line nested list comprehensions."
    - path: "src/*"
      guideline: "Do not leave in commented out code. Delete it."
    - path: "*"
      guideline: "Correct grammar and spelling mistakes. Do not comment on writing style. Allow for flexible capitalization and abbreviation for variable names."
    - path: "*.ts"
      guideline: "Follow our TypeScript style guide."
      context_document_path: "docs/CONTRIBUTING.md"
    - path: "*"
      guideline: "Follow all of our engineering best practices."
      context_document_path: "https://factory-ai.atlassian.net/wiki/spaces/factory/pages/9338882/Best+Practices"

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Components of a Guideline

  • path: An fnmatch pattern specifying which file paths this guideline applies to.
  • guideline: The specific issue you want Droid to comment on, preferably including a suggestion for how to fix it.
  • context_document_path (optional): Specifies a document that provides additional context to Review Droid when enforcing the guideline. This can be either:
    • A path to a document from the repository root
    • A URL to a Confluence page

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Best Practices for Writing Guidelines

To make the most of Review Droid Guidelines, follow these best practices:
  1. Be Specific and Actionable: Ensure your guidelines are clear and lead to actionable changes. Vague guidelines can result in inconsistent reviews and misunderstandings.
  2. Complement Existing Tools: Guidelines should complement other tools like linters and type checkers, not replace them. Use guidelines for aspects that are not easily automated, such as code structure and logic.
  3. Maintain Contextual Relevance: Tailor your guidelines to the specific context of the code. Different parts of the codebase may require different focus areas during review.
  4. Use Examples: When possible, provide examples of both good and bad practices in your guidelines to make them more clear and effective.
  5. Keep Guidelines Up-to-Date: Regularly review and update your guidelines as your project evolves and coding standards change.

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Guideline Examples

Here are some examples of effective guidelines for different aspects of code review:

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Bugs & Errors

- path: "src/*"
  guideline: "Catch obvious bugs"

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Readability

- path: "src/*.py"
  guideline: "Don't use multi-line nested list comprehensions. Break them down into multiple statements for better readability."

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Error Handling

- path: "src/*.py"
  guideline: "Ensure all file operations are wrapped in try/except blocks to handle I/O errors gracefully."

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Security

- path: "src/*.py"
  guideline: "Validate all user inputs to prevent SQL injection and XSS attacks. Use parameterized queries and escape HTML output."

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Documentation

- path: "src/*.py"
  guideline: "Ensure all public functions have docstrings that describe their purpose, parameters, and return values."

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Feedback Mechanism

Review Droid incorporates a feedback mechanism to continuously improve the effectiveness of the guidelines. During the review process, reviewers can provide feedback on each guideline using thumbs up or thumbs down reactions.
  • Thumbs Up: Indicates that the guideline was helpful and should continue to be used in future reviews.
  • Thumbs Down: Indicates that the guideline was not helpful or needs improvement.
This feedback loop ensures that the guidelines evolve over time based on real-world usage and reviewer experiences, leading to more accurate and valuable review comments.

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Conclusion

By setting up effective Review Droid Guidelines, you can significantly enhance the quality and consistency of your code reviews. Remember to start with a few key guidelines and gradually expand as you learn what works best for your team and project.

Next: Cloud Development Environments

Learn how to set up Cloud Development Environments for optimal Droid performance