GitHub Copilot Instructions for dotnet/SqlClient

🧑‍💻 Roles and Responsibilities

• Triage: Review new issues, categorize them, and assign them to appropriate team members.
• Fixing Issues: Address bugs, implement feature requests, and complete tasks as assigned.
• Writing Tests: Ensure all changes are covered by unit tests and integration tests.
• Documentation: Update documentation for public APIs, features, and usage examples.
• Pull Requests: Create and submit PRs for review, ensuring they follow project conventions and include necessary tests and documentation.
• Code Reviews: Review PRs from other contributors, providing feedback and suggestions for improvements.
• Continuous Improvement: Identify areas for improvement in the code base, documentation, and processes, and implement changes to enhance the project.

📚 Project Overview

This project is a .NET data provider for SQL Server, enabling .NET applications to interact with SQL Server databases. It supports various features like connection pooling, transaction management, and asynchronous operations. The project builds from a single unified project at src/Microsoft.Data.SqlClient/src/Microsoft.Data.SqlClient.csproj, targeting net462;net10.0 (minimum runtime compatibility: .NET Framework 4.6.2 and .NET 10). Public API declarations are unified under src/Microsoft.Data.SqlClient/ref/; reference and unsupported-platform projects additionally preserve netstandard2.0. The legacy netfx/ and netcore/ directories are no longer used. The project includes:

• Public APIs: Defined by src/Microsoft.Data.SqlClient/ref/Microsoft.Data.SqlClient.csproj and the reference source files beside it.
• Implementations: All source code in src/Microsoft.Data.SqlClient/src/.
• Tests: Located in the tests/ directory, covering unit and integration tests.
  • Unit Tests: Located in src/Microsoft.Data.SqlClient/tests/UnitTests/.
  • Functional Tests: Located in src/Microsoft.Data.SqlClient/tests/FunctionalTests/.
  • Manual Tests: Located in src/Microsoft.Data.SqlClient/tests/ManualTests/.
  • Performance/Stress Tests: Located in src/Microsoft.Data.SqlClient/tests/PerformanceTests/ and src/Microsoft.Data.SqlClient/tests/StressTests/.
• Documentation: Found in the doc/ directory, including API documentation, usage examples.
• Policies: Contribution guidelines, coding standards, and review policies in the policy/ directory.
• Building: The repo uses build.proj for orchestrated build/test/pack workflows, src/Microsoft.Data.SqlClient.slnx for solution-centric development tooling, and Azure DevOps YAML under eng/pipelines/ plus eng/pipelines/onebranch/ for CI and official release flows. See BUILDGUIDE.md for local build details.
• CI/CD: ADO Pipelines for CI/CD and Pull request validation are defined in the eng/ directory, ensuring code quality and automated testing.

📦 Products

This project includes several key products and libraries that facilitate SQL Server connectivity and data access:

• Microsoft.Data.SqlClient: The primary library for SQL Server data access, providing a rich set of APIs for connecting to SQL Server databases, executing commands, and retrieving data.
• Microsoft.Data.SqlClient.AlwaysEncrypted.AzureKeyVaultProvider: Enables Always Encrypted with Azure Key Vault integration, allowing SQL Server column encryption and decryption using keys managed in Azure Key Vault.
• Microsoft.SqlServer.Server: Supplies APIs for SQL Server-specific features, including user-defined types (UDTs) and SQL Server-specific attributes.

🛠️ Key Features

• Connectivity to SQL Server: Provides robust and secure connections to SQL Server databases, using various authentication methods, such as Windows Authentication, SQL Server Authentication, and Entra ID authentication, e.g. ActiveDirectoryIntegrated, ActiveDirectoryPassword, ActiveDirectoryServicePrincipal,ActiveDirectoryInteractive, ActiveDirectoryDefault, and ActiveDirectoryManagedIdentity.
• Connection Resiliency: Implements connection resiliency features to handle transient faults and network issues, ensuring reliable database connectivity.
• TLS Encryption: Supports secure connections using TLS protocols to encrypt data in transit. Supports TLS 1.2 and higher, ensuring secure communication with SQL Server. Supported encryption modes are:
  • Optional: Encryption is used if available, but not required.
  • Mandatory: Encryption is mandatory for the connection.
  • Strict: Enforces strict TLS requirements, ensuring only secure connections are established.
• TLS 1.3 Support: Supports TLS 1.3 for enhanced security and performance in data transmission when connecting with 'Strict' encryption mode.
• TDS Protocol: Implements the Tabular Data Stream (TDS) protocol for communication with SQL Server, supported protocol versions include TDS 7.4 and 8.0.
• Data Access: Supports executing SQL commands, retrieving data using SqlDataReader, and managing data with SqlCommand and SqlConnection objects.
• MultipleActiveResultSets (MARS): Supports Multiple Active Result Sets, allowing multiple active commands to be executed on a single connection.
• Asynchronous Operations: Supports async/await patterns for non-blocking database operations.
• Connection Pooling: Efficiently manages database connections in pools to improve performance.
• Transaction Management: Supports transaction management using local transaction management and Global transactions using MSDTC for data integrity and consistency.
• Parameterization: Supports prevention of SQL injection attacks by using parameterized queries.
• Data Types: Supports a wide range of SQL Server data types, including Json, Vector, custom types and UDTs.
• Data Encryption: Supports data encryption for secure data transmission.
• Logging and Diagnostics: Provides event source tracing diagnostic capabilities for troubleshooting.
• Failover Support: Handles automatic failover scenarios for high availability.
  • Compatibility switch: Switch.Microsoft.Data.SqlClient.UseLegacyFailoverAlternationOnLoginSqlErrors (default false) can restore legacy alternation behavior in LoginWithFailover for login-phase SQL errors.
• Cross-Platform Support: Compatible with .NET Framework 4.6.2+ on Windows and .NET 10+ on Windows, Linux, and macOS.
• Column Encryption AKV Provider: Supports Azure Key Vault (AKV) provider for acquiring keys from Azure Key Vault to be used for encryption and decryption.

🧩 SNI Implementations

There are two implementations of the SQL Server Network Interface (SNI) layer used in this project:

• Managed SNI: A managed implementation of SNI that is used in .NET 10+ environments. It provides cross-platform support for SQL Server connectivity.
• Native SNI: A native implementation of SNI that is used in .NET Framework and .NET Core environments on Windows. It's shipped as part of the Microsoft.Data.SqlClient.SNI and Microsoft.Data.SqlClient.SNI.Runtime packages.
  • Microsoft.Data.SqlClient.SNI: This package provides the native SNI layer for .NET Framework applications.
  • Microsoft.Data.SqlClient.SNI.Runtime: This package provides the native SNI layer for .NET Core applications on Windows.

📌 Instructions for Copilot

🐛 Triage Issues

When a new issue is created, follow these steps:

1. Acknowledge Receipt: Respond within 48 hours to confirm the issue is being triaged.
2. Set Issue Type:
   • Update issue type as Bug, Feature, Task, or Epic if not done already, based on:
     • Use Bug for issues opened following ISSUE_TEMPLATE\bug-report.md template, and is complaining about an unexpected behavior.
     • Use Feature for issues opened following ISSUE_TEMPLATE\feature_request.md template, containing proposals to incorporate.
     • Use Task for issues opened as sub-issues.
     • Use Epic for issues acting as a high-level work linked to multiple sub-issues.
3. Request Missing Information: If any required details are missing based on the issue template, ask the reporter to provide them.
4. Labeling: Apply appropriate labels like Area\Engineering, Area\Json, Area\AKV Provider, Area\Connection Pooling, etc. based on the issue content.
   • Use Triage Needed :new: for new issues that need initial review.
   • Use Performance :chart_with_upwards_trend: for issues that are targeted to performance improvements/concerns.
   • Use Needs more info :information_source: for issues that require additional information.
5. Link Related Issues: If the issue is related to other issues, link them for better context.
6. Add Comments: As you triage issues, comment on the issue to:
   • Confirm receipt and triage status.
   • Ask for any missing information.
   • Provide initial thoughts or questions to clarify the issue.
   • Include links to relevant documentation or code examples.
   • Use the @ mention feature to notify relevant team members or stakeholders.

🛠️ Fixing Issues

• Focus on issues assigned to you.
• For issues labeled Needs more info :information_source:, ask for clarifications or additional details.
• For issues labeled Performance :chart_with_upwards_trend:, prioritize performance-related improvements.
• Use the issue description to understand the problem and identify the root cause.
  • If the issue is a bug, ensure you can reproduce it with the provided code sample.
  • If the issue is a feature request, review the proposal and assess its feasibility.
  • If the issue is a task, follow the instructions provided in the issue description.
  • If the issue is an epic, break it down into smaller tasks or bugs and create sub-issues as needed.
• Cross-reference issue descriptions with code in src/Microsoft.Data.SqlClient/src/. Do NOT add code to the legacy netfx/src/ or netcore/src/ directories.
• If public APIs are changed, update corresponding ref/ projects.
• Add or update tests in tests/ to validate the fix.

🧪 Writing Tests

• For every bug fix, ensure there are unit tests and manual (integration) tests that cover the scenario.
• For new features, write tests that validate the functionality.
• Follow a test-driven approach: write failing tests before implementing fixes.
• Cover both sync and async code paths where the API exposes both variants (e.g., Open/OpenAsync, ExecuteReader/ExecuteReaderAsync). Sync and async implementations often differ internally.
• Use the existing test framework in the tests/ directory.
• Follow the naming conventions and structure of existing tests.
• Ensure tests are comprehensive and cover edge cases.
• If the issue involves changes to public APIs, update the corresponding ref/ projects to reflect those changes.
• Add sample code snippets in the 'doc/samples/' directory to demonstrate the new or fixed functionality and link them in the documentation in doc/ folder.

📝 Documentation

• All public documentation for APIs should be updated in the doc/ directories.
• When adding or changing XML docs, ensure they are clear and follow the existing style.

🔁 Creating Pull Requests

• Use the Fixes #issue_number syntax in the PR description to automatically close the issue when the PR is merged.
• Include a summary of the fix and link to the related issue
• Add [x] checkboxes for:
  • Tests added or updated
  • Public API changes documented
  • Verified against customer repro (if applicable)
  • Ensure no breaking changes introduced
• Ensure the PR passes all CI checks before merging.

✅ Closing Issues

• Add a comment summarizing the fix and referencing the PR

⚙️ Automating Workflows

• Auto-label PRs based on folder paths (e.g., changes in src/Microsoft.Data.SqlClient/src/ → Area\SqlClient, changes in tests/ → Area\Testing) and whether they add new public APIs or introduce a breaking change.
• Suggest release note entries for fixes by updating files under release-notes/ or by using the release-notes prompt (instead of editing CHANGELOG.md directly).
• Tag reviewers based on CODEOWNERS file

🌿 Branch Naming

• Interactive agents, working under direct human guidance, may create and use branches under dev/<name>/ when the human specifies or approves the namespace and branch name (e.g., dev/paul/aot/phase-1.1).
• Autonomous agents, working without interactive human direction, must create branches under dev/automation/ (e.g., dev/automation/fix-connection-timeout).
• Do not create branches outside these namespaces or directly under dev/.

🧠 Contextual Awareness

• All source code is in src/Microsoft.Data.SqlClient/src/. Do NOT add code to legacy netfx/src/ or netcore/src/ directories.
• Public API changes must update the unified src/Microsoft.Data.SqlClient/ref/ sources for each affected target framework.
• Check for platform-specific differences using file suffixes (.netfx.cs, .netcore.cs, .windows.cs, .unix.cs) and conditional compilation (#if NETFRAMEWORK, #if NET, #if _WINDOWS, #if _UNIX).
• Respect API compatibility rules across .NET versions
• Do not introduce breaking changes without proper justification and documentation
• Use the doc/ directory for any new documentation or updates to existing documentation
• Use the tests/ directory for any new tests or updates to existing tests
• Use the doc/samples/ directory for any new code samples or updates to existing samples
• Use the policy/ directory for any new policies or updates to existing policies

Constraints

• Do not modify the CODEOWNERS file directly.
• Do not modify CHANGELOG.md unless executing a release workflow (see release-notes prompt).
• Do not close issues without a fix or without providing a clear reason.

Terminal Execution Safety

• Treat any non-zero shell exit code as a failed step that requires correction before proceeding.
• If a bash process exits, do not wait for more output from that process; rerun the command in a fresh terminal session.
• Validate that expected command output was produced before using it as evidence for conclusions.
• When terminal execution fails, surface the failure immediately and retry with a corrected command.
• Avoid set -e in this automation workflow; use focused commands and verify each result explicitly so shell exits are observable and attributable.
• Prefer short, single-purpose terminal commands over long chained scripts when debugging or gathering state.

📝 Notes

• Update policies and guidelines in the policy/ directory as needed based on trending practices and team feedback.
• Regularly review and update the doc/ directory to ensure it reflects the current state of the project.