Contributing to Prisma Engines

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Welcome Contributors

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Before You Start

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External Contributions

• Your work aligns with project direction
• You don’t duplicate existing efforts
• The implementation approach is acceptable
• Your time is well spent

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Good First Contributions

• How to run quaint tests
• How to run schema engine tests

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Code of Conduct

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Key Principles

• Good faith collaboration - Trust that disagreements come from different perspectives, not bad intentions
• Respectful interaction - How you act reflects on both you and the project
• Open and inclusive - The community thrives on diversity and welcomes all contributors
• Self-regulation - Be quick to apologize and correct course, even if you’re not entirely convinced you need to

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Bad Actors

• Alienate other contributors
• Discourage collaboration
• Reflect poorly on the project as a whole

• Being quick to apologize
• Correcting course even if unsure it’s necessary
• Giving other contributors the benefit of the doubt
• Having a sincere willingness to admit you might be wrong

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Development Workflow

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1. Set Up Your Environment

git clone https://github.com/YOUR_USERNAME/prisma-engines.git
cd prisma-engines

direnv allow

cargo build

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2. Create a Branch

git checkout -b fix/schema-validation-error
git checkout -b feat/add-query-optimization
git checkout -b docs/improve-testing-guide

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3. Make Your Changes

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Code Changes

• Follow existing code style and conventions
• Add tests for new functionality
• Update relevant documentation
• Keep changes focused and atomic

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Documentation Changes

• Use clear, concise language
• Include code examples where helpful
• Test that code examples actually work
• Update navigation if adding new pages

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4. Test Your Changes

make test-unit

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5. Update Snapshots (if needed)

UPDATE_EXPECT=1 cargo test -p prisma-fmt
UPDATE_EXPECT=1 cargo test -p query-compiler

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6. Format and Lint

# Format code
cargo fmt

# Run clippy
cargo clippy --all-features --all-targets -- -Dwarnings

# Or run both with pedantic check
make pedantic

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7. Commit Your Changes

git add .
git commit -m "fix(schema-engine): handle null values in introspection

Previously, null values in certain MySQL column types would cause
introspection to fail. This adds proper null handling and test coverage.

Fixes #1234"

• Start with a type: fix, feat, docs, test, refactor, perf, chore
• Include component in parentheses: (schema-engine), (query-compiler), (psl)
• Provide context in the body
• Reference related issues

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8. Push and Create PR

git push -u origin your-branch-name

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Pull Request Guidelines

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PR Title

feat(query-compiler): add support for JSON filtering
fix(schema-engine): resolve migration shadow database issue
docs: improve connector test kit documentation

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PR Description

1. What - What does this PR do?
2. Why - Why is this change needed?
3. How - How does it work? (for complex changes)
4. Testing - How was it tested?
5. Breaking Changes - Any breaking changes?
6. Related Issues - Links to issues

## What
Adds support for filtering JSON fields in PostgreSQL queries.

## Why
Users need to filter on JSON field values without using raw SQL.
Fixes #4567

## How
Implements JSON path syntax in the query compiler and translates
to PostgreSQL's `->` and `->>` operators.

## Testing
- Added unit tests in query-compiler
- Added integration tests in connector-test-kit
- Verified with PostgreSQL 13, 14, 15

## Breaking Changes
None

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Linking prisma/prisma Branch

1. Create a branch in prisma/prisma with your adapter/client changes
2. Add this tag to your PR description on a separate line:

/prisma-branch your/branch-name

1. Merge the prisma/prisma PR first
2. Then merge the prisma/prisma-engines PR

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Integration Testing

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Automated Integration Releases

git checkout -b integration/my-feature

1. Run full test suite
2. Build and release engines to S3/R2
3. Trigger engines-wrapper update
4. Create automated PR in prisma/prisma
5. Publish to npm on integration tag
6. Run ecosystem tests

git commit -m "feat: my feature [integration]"

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Testing from Forks

# Checkout the fork's PR
gh pr checkout 4375

# Create integration branch
git checkout -b integration/sql-nested-transactions

# Push to main repository
git push --set-upstream origin integration/sql-nested-transactions

git branch --delete integration/sql-nested-transactions
gh pr checkout 4375
git checkout -b integration/sql-nested-transactions
git push --set-upstream origin integration/sql-nested-transactions --force

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Code Review Process

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What to Expect

• Reviews may take time - be patient
• Reviewers may request changes
• Be responsive to feedback
• Discussions are about code, not you personally

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Responding to Feedback

• Address all comments
• Ask questions if unclear
• Explain your reasoning when disagreeing
• Update code based on accepted feedback
• Mark conversations as resolved after addressing

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Review Iterations

# Make requested changes
git add .
git commit -m "address review feedback"
git push

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Coding Standards

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Rust Style

• Follow standard Rust conventions
• Use cargo fmt for formatting
• Address all cargo clippy warnings
• Write idiomatic Rust
• Prefer explicit over implicit

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Testing Requirements

• Add tests for new features
• Maintain or improve test coverage
• Integration tests for user-facing changes
• Update snapshots when changing output

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Documentation

• Document public APIs
• Add inline comments for complex logic
• Update README when adding features
• Include examples in documentation

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Error Handling

• Use proper error types
• Provide helpful error messages
• Include context in errors
• Don’t panic in library code

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Common Pitfalls

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CRLF vs LF Line Endings

# If Git warns about line endings
git checkout HEAD -- path/to/file

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Snapshot Updates

# Good: Review first
UPDATE_EXPECT=1 cargo test -p prisma-fmt
git diff  # Review changes

# Bad: Blind update
UPDATE_EXPECT=1 cargo test && git add -A && git commit -m "update snapshots"

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Missing Database URLs

# Set up before running tests
source .test_database_urls/postgres
cargo test -p sql-migration-tests

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Feature Flag Confusion

# Wrong - may fail
cargo test -p psl

# Right - includes all features
cargo test -p psl --features all

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Getting Help

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Ask Questions

• GitHub Discussions - General questions
• GitHub Issues - Bug reports, feature requests
• Slack - Real-time chat (for contributors)
• PR Comments - Questions about your PR

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Resources

• Building Guide
• Testing Guide
• Debugging Guide
• API Documentation
• Prisma Documentation

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Recognition

• Contributors listed in release notes
• Credit in commit history
• Community appreciation
• Building better tools for everyone

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Security

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License