Release

VS handles the progression from main → rel/insiders → rel/stable on its own schedule. MSBuild's responsibility is to have final-branded bits in VS main before the insiders snap date.

Each monthly VS release produces:

• A new vs* branch from main
• Final branding on that branch
• A version bump in main
• DARC channel/subscription updates
• A VS insertion
• Post-GA publishing to nuget.org and docs

The process is organized into 6 timeline-gated phases (0–5), each with an explicit trigger.

Execution model: This skill is designed for an interactive Copilot session. The agent walks through each phase step-by-step, but every command that modifies state (git push, DARC writes, pipeline changes, PR creation) requires user approval before execution. Read-only queries (DARC get-*, git log, etc.) can run without approval.

Required Inputs

Before starting any phase, ensure you have these values (the user must provide them — version increments are irregular and cannot be computed):

Prerequisites

• gh cli
• az cli
• darc cli

Phase Summary

DARC Batching

DARC write commands push to the maestro-configuration repo. Batch related changes into one PR:

1. Choose a branch name like release/msbuild-{{THIS_RELEASE_VERSION}}
2. Add --configuration-branch <name> --no-pr to every write command except the last
3. Last command: use --configuration-branch <name> without --no-pr to create the PR
4. Get the PR reviewed and merged

Read-only commands (get-default-channels, get-subscriptions, get-channel) don't need these flags.

Executing a Phase

When asked to execute a specific phase:

1. Read the full phase from documentation/release-checklist.md
2. Verify the trigger condition is met (previous phases completed)
3. Execute steps in order — respect sequential/parallel annotations
4. For DARC commands: batch writes into one configuration PR per phase
5. Record all output URLs in the tracking issue's artifact table
6. Mark checkboxes as completed in the tracking issue

Key Files

Validation

After completing all phases, verify:

1. Branch vs{{THIS_RELEASE_VERSION}} exists and has final branding
2. Main has VersionPrefix = {{NEXT_VERSION}}.0
3. DARC: main → VS {{NEXT_VERSION}} channel, release branch → VS {{THIS_RELEASE_VERSION}} channel
4. VS insertion PR merged
5. Packages published to nuget.org
6. GitHub release created with tag v{{THIS_RELEASE_EXACT_VERSION}}

Error Recovery

• Branch already exists: Release was partially started — check the tracking issue for progress
• DARC channel already exists: Safe to continue — add-channel is idempotent
• Stabilize-Release.ps1 says "already stabilized": Skip — idempotent
• OptProf fails on first build: Expected — that's why we use main's OptProf data as fallback
• DARC configuration PR conflicts: Rebase the configuration branch on production and force-push

Major Version Releases

If NEXT_VERSION is a new major version (e.g., 18.x → 19.0), additional steps are needed after Phase 5. See release.md for:

• src/Shared/BuildEnvironmentHelper.cs — VS major version constants
• src/Shared/Constants.cs — version constants
• src/Framework/Telemetry/TelemetryConstants.cs — telemetry version