Update Roslyn Version

This skill describes how to update the Roslyn language server version in the vscode-csharp repository.

Prerequisites

1. You must have a local clone of the dotnet/roslyn repository. Common locations for this include:

• C:\Users\<username>\source\repos\roslyn
• Next to the current repo directory, e.g. <current-repo-root>/../roslyn
• If unable to find local roslyn repo, ask the user for its location.

2. The dnx command must be available. It is included with the .NET 10 SDK and later:

   dnx --help
   

3. The GitHub CLI must be installed and authenticated so its token can be passed to Roslyn Tools:

   gh auth status
   

Input Required

• New Roslyn Version (optional): The new version to update to (e.g., 5.5.0-2.26080.10). If not provided, the version will be auto-discovered from the latest passing dotnet-roslyn-official pipeline build on main. See Version Auto-Discovery below.

Version Auto-Discovery

If the user does not provide a specific Roslyn version, follow these steps to discover the latest version from the official Roslyn build pipeline.

Prerequisites

1. The Azure Developer CLI (azd) must be installed. See https://learn.microsoft.com/azure/developer/azure-developer-cli/install-azd for platform-specific instructions.
   • If azd is missing, don't look for an alternative. Instead, stop and assist the user with installing it.
2. You must be authenticated:

   azd auth login
   

Discovery Steps

1. Get an Azure DevOps bearer token:

   TOKEN=$(azd auth token --scope "499b84ac-1321-427f-aa17-267ca6975798/.default" --output json | jq -r '.token')
   

2. Find the latest passing main build (pipeline definition ID 327 = dotnet-roslyn-official):

   BUILD_ID=$(curl -s -H "Authorization: Bearer $TOKEN" \
     "https://dnceng.visualstudio.com/internal/_apis/build/builds?definitions=327&branchName=refs/heads/main&statusFilter=completed&resultFilter=succeeded&\$top=1&api-version=7.0" \
     | jq '.value[0].id')
   

3. Find the "Publish Assets" task log URL from the build timeline:

   LOG_URL=$(curl -s -H "Authorization: Bearer $TOKEN" \
     "https://dnceng.visualstudio.com/internal/_apis/build/builds/$BUILD_ID/timeline?api-version=7.0" \
     | jq -r '.records[] | select(.name == "Publish Assets" and .type == "Task") | .log.url')
   

4. Fetch the log and extract the NuGet package version:

   VERSION=$(curl -s -H "Authorization: Bearer $TOKEN" "$LOG_URL" \
     | grep -oP 'Microsoft\.CodeAnalysis\.\K\d+\.\d+\.\d+-[\w.]+(?=\.nupkg)' \
     | head -1)
   echo "Discovered version: $VERSION"
   

The extracted version (e.g., 5.6.0-2.26173.1) is the value to use as the new Roslyn version for the rest of the process.

Process

Step 1: Create a New Branch

Create a new git branch for the update:

git checkout -B update/roslyn-<version>

Replace <version> with the new Roslyn version, using dashes instead of dots for the branch name.

Step 2: Update package.json

Update the defaults.roslyn field in package.json:

"defaults": {
    "roslyn": "<new-version>",
    ...
}

Step 3: Run updateRoslynVersion

This step acquires the new Roslyn packages and ensures they are in the proper feeds:

npm run updateRoslynVersion

This task:

• Downloads all platform-specific Roslyn nuget packages
• Ensures packages are saved to the consumption AzDo artifacts feed
• Runs installDependencies to update local dependencies

Note: You may need to install the Azure Artifacts NuGet Credential Provider for interactive authentication.

Step 4: Get the Previous Roslyn Commit SHA

The commit SHAs are stored in the .nuspec files inside the downloaded NuGet packages. After running npm run updateRoslynVersion, the new version's package will be cached locally, but you need to explicitly download the old version to get its commit SHA.

To get the old version's commit SHA:

1. First, find the old version number from the current package.json (before your edit) - look at the defaults.roslyn value
2. Download the old version's package to the local cache:

   dotnet restore "C:\Users\<username>\source\repos\vscode-csharp\msbuild\server" /p:PackageName=roslyn-language-server.osx-arm64 /p:PackageVersion=<old-version> --interactive
   

3. Extract the commit SHA from the nuspec file:

   Get-Content "C:\Users\<username>\source\repos\vscode-csharp\out\.nuget\roslyn-language-server.osx-arm64\<old-version>\roslyn-language-server.osx-arm64.nuspec" | Select-String -Pattern "commit"
   

   This will show output like:

   <repository type="git" url="https://github.com/dotnet/roslyn" branch="main" commit="0e21a3cb684db6ab02646541a780b3278f53d19e" />
   

Step 5: Get the New Roslyn Commit SHA

After running npm run updateRoslynVersion, the new version's package is already cached. Extract the commit SHA:

Get-Content "C:\Users\<username>\source\repos\vscode-csharp\out\.nuget\roslyn-language-server.osx-arm64\<new-version>\roslyn-language-server.osx-arm64.nuspec" | Select-String -Pattern "commit"

Note: The Azure DevOps artifacts feed web pages require authentication and may not load properly in automated scenarios. Always use the nuspec files from the local package cache.

Step 6: Generate Changelog Entries Using PR Finder

First, locate the local dotnet/roslyn repository. Common locations include:

• C:\Users\<username>\source\repos\roslyn
• C:\repos\roslyn

Navigate to the roslyn repository, fetch the latest, and run the pr-finder tool:

cd <path-to-roslyn-repo>
git fetch origin
dnx Microsoft.RoslynTools --prerelease --source https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-tools/nuget/v3/index.json -- pr-finder --github-token "$(gh auth token)" --start <old-commit-sha> --end <new-commit-sha> --format "o#"

Important: Invoke Roslyn Tools through dnx instead of a globally installed roslyn-tools executable. Always pass the GitHub token explicitly with --github-token.

This will output a list of PRs in the format needed for the changelog:

  * <PR title> (PR: [#<number>](https://github.com/dotnet/roslyn/pull/<number>))

Keep the raw output from pr-finder; you'll use it unchanged in the pull request description in Step 10.

Step 7: Update CHANGELOG.md

Add an entry to CHANGELOG.md under the current version section (e.g., # 2.121.x): Copy the results from the previous step (should already be formatted correctly).

* Update Roslyn to <new-version> (PR: [#](https://github.com/dotnet/vscode-csharp/pull/))
  * <PR title 1> (PR: [#<number>](https://github.com/dotnet/roslyn/pull/<number>))
  * <PR title 2> (PR: [#<number>](https://github.com/dotnet/roslyn/pull/<number>))
  ...

Note: Leave the PR number blank initially (just [#]) - it will be updated after the PR is created.

Step 8: Filter Changelog Entries

Treat the changelog as a concise list of user-facing VS Code editor and language server changes, not a list of all production changes in Roslyn. Review the PR title and, when its impact is ambiguous, its changed files or description.

Remove entries that are:

• Infrastructure/Build changes: CI/CD pipelines, build scripts, Azure DevOps configurations
• Visual Studio-only changes: Features or fixes specific to Visual Studio IDE (not VS Code)
• Test-only changes: Test infrastructure, test fixes that don't affect production code
• Internal tooling: Changes to internal tools not used by the language server
• Documentation-only: README updates, internal docs (unless they document user-facing features)
• Compiler-only changes: Language implementation, parsing, lowering, emit, code generation, compiler APIs, or compiler performance changes without direct editor or language server impact
• Razor compiler internals: Razor parsing, lowering, code generation, or compiler architecture changes that do not directly change the VS Code editing experience
• Internal refactoring and dependencies: Architectural refactors, implementation details, package updates, or internal performance work unless they have a clear user-visible effect in VS Code

Keep entries that are:

• Language server protocol (LSP) changes
• Code analysis or diagnostics improvements visible in the editor
• Completion, navigation, refactoring features
• Performance improvements specifically affecting editor or language server responsiveness
• Bug fixes that affect language server behavior
• Razor changes that directly affect editing features such as formatting, completion, navigation, or code actions
• API changes consumed by the VS Code extension or language server

When uncertain, omit the entry from CHANGELOG.md; the complete unfiltered list remains available in the pull request description.

Step 9: Commit and Push

git add package.json CHANGELOG.md
git commit -m "Update Roslyn to <new-version>"
git push -u origin update/roslyn-<version>

Step 10: Create Pull Request

Create a pull request on GitHub:

• Title: Update roslyn to <new-version>
• Base: main
• Description/body: the raw, unfiltered output from pr-finder in Step 6, including the compare link and full PR list exactly as produced by the tool. Do not apply the Step 8 changelog filtering to the PR description.

Step 11: Update Changelog with PR Number

After the PR is created, note the PR number (e.g., #8941), then:

1. Update the CHANGELOG.md entry to include the actual PR number:

   * Update Roslyn to <new-version> (PR: [#8941](https://github.com/dotnet/vscode-csharp/pull/8941))
   

2. Commit and push the update:

   git add CHANGELOG.md
   git commit -m "Update changelog with PR number"
   git push
   

Example

For updating from 5.4.0-2.26077.7 to 5.5.0-2.26080.10:

1. Branch: update/roslyn-5-5-0-2-26080-10
2. package.json change: "roslyn": "5.5.0-2.26080.10"
3. Find old commit from package metadata for version 5.4.0-2.26077.7
4. Find new commit from package metadata for version 5.5.0-2.26080.10
5. Run pr-finder in roslyn repo
6. Update CHANGELOG.md with the output
7. Run npm run updateRoslynVersion
8. Create PR titled "Update roslyn to 5.5.0-2.26080.10"
9. Update changelog with PR number

Reference PR

See PR #8941 as an example of a Roslyn version update.

Files Modified

• package.json - Update defaults.roslyn version
• CHANGELOG.md - Add changelog entry with Roslyn PR list

Troubleshooting

Authentication Issues with updateRoslynVersion

If you encounter authentication errors:

1. Install Azure Artifacts Credential Provider
2. Run the command again - it should prompt for interactive authentication

pr-finder Returns Empty Results

Ensure:

1. You have fetched the latest from origin in the roslyn repo: git fetch origin
2. Both commit SHAs exist in your local repo
3. gh auth status succeeds and gh auth token returns a token
4. You are invoking the tool through dnx and passing --github-token "$(gh auth token)"

Finding Commit SHAs

The commit SHAs are embedded in the nuspec files inside the downloaded NuGet packages:

1. After running npm run updateRoslynVersion, packages are cached in out/.nuget/
2. To get the old version's commit, you may need to explicitly download it first:

   dotnet restore "msbuild\server" /p:PackageName=roslyn-language-server.osx-arm64 /p:PackageVersion=<old-version> --interactive
   

3. Then read the nuspec file:

   Get-Content "out\.nuget\roslyn-language-server.osx-arm64\<version>\roslyn-language-server.osx-arm64.nuspec" | Select-String -Pattern "commit"
   

Note: The Azure DevOps artifacts feed web pages require authentication and often fail to load in automated scenarios. Always use the local nuspec files instead.